KINETICS AND MECHANICS OF THE REACTION OF

HYDRAZOIC ACID WITH SUBSTITUTED BENZOIC ACIDS

DISSERTATION

Presented in Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy in the Graduate School of the Ohio State U n iversity

B y

MELVILLE ERNEST DOUGLAS HILLMAN, B .A ., M.Sc,

++++++

The Ohio State University 1958

Approved by

Department of Chemistry ACKNOWIÆDGMENTS

The author wishes to express his appreciation to Dr, Harold

Shechter for his suggestion of this problem, for his guidance and encouragement during the course of the investigation, and for his assistance in the preparation of the manuscript.

The author is grateful to the Lubrizol Corporation the Socony-

Mobile Company and to the Chemistry Department of The Ohio

State University for fellowship funds. He also wishes to thank fellow graduate students and members of the staff for their cooperation in innumerable ways.

The author is deeply grateful to his wife, Freda, for per­ forming some of the analyses and for taking over the difficult task of organizing and typing the various drafts of the dissertation.

11 CONTENTS

Page

I. INTRODUCTION...... 1

II. HISTORICAL...... 4

The Schmidt Reaction ...... 4 The Curtins Reaction ...... 23 The Hammett Equation ...... 28 Acidity Functions ...... 33 in. DISCUSSION OF RESULTS...... 41

Kinetic Order of the Schmidt Reaction...... 41 Leveling of Solvent ...... 42 Decomposition of Hydrazoic Acid...... 43 Effect of Acidity on tlie Schmidt Reaction...... 48 Proximity Effects...... 67 Electrical Effects ...... 72 Activation Param eters...... 84

IV. EXPERIMENTAL...... 97

Preparation and Purification of Aromatic A cids,..... 97 o-Isopropylbenzoic Acid...... 97 o-tert-Butylbenzoic Acid...... 101 2, 6 -Dimethylbenzoic A cid...... 106 2, 3-Dimethylbenzoic Acid...... 108 Purification of Substituted Benzoic Acids...... 109 Determination of the Kinetic Constants...... I l l Constant Temperature Baths ...... I l l K in etic P ro ced u re...... 112 Spectrophotometric Techniques...... 112 Sulfuric Acid Solutions ...... 115 Sodium Azide and Hydrazoic Acid Solutions 115 Execution of Kinetic Experiments 117 T reatment of Kinetic Data...... 121 Rate Constants...... 122 Activation Parameters ...... 125

APPENDIX ...... 127

AUT OBIOGRAPH Y...... 319

iii LIST OF FIGURES

Figure Page

1 -2„ Decomposition of Hydrazoic Acid ...... 45-46

3-6, Acidity Correlations for Reaction of £-Toluic A cid ...... 54-57

7. Hammett Plot for Reactions of m- and p- Substituted Benzoic Acids...... 76

8 . Enthalpy - Entropy Plot for Reactions of Substituted Benzoic Acids...... 91

9-12, Activation Energy Plots for Reactions of Substituted Benzoic A cids...... 128-131

13-18. Representative Plots of l/c versus time for Reactions of Substituted Benzoic Acids...... 132-137

19-36. UV Absorption Spectra of Substituted Benzoic Acids and Substituted Anilines, ...... 138-146

37. Acidity Correlation for Reaction of ^-Toluic A cid ...... 147

IV LIST OF TABLES

TEXT

Table Page

1. The Schmidt Réaction of Substituted Benzoic Acids .... 9

2. The Schmidt Reaction of QuinolinecaxboxyXic Acids ... 19

3. Acidity Functions and Rate Constants for the Schmidt Reaction of o^-Toluic Acid at 24, 3®...... 62

4. Rate Constants for Reaction of Hydrazoic Acid with Substituted Benzoic Acids ...... 68-69

5. Activation Parameters for Reaction of Hydrazoic Acid with Substituted Benzoic Acids...... 74

6 . Physical Constants for the Substituted Benzoic Acids .110

APPENDIX

1-28. Collected Velocity Constants for the Schmidt Reactions of Substituted Benzoic A cids...... 148-161

' 29-159. Kinetic Data for the Schmidt Reactions of (O-Substituted Benzoic A cid s...... 162-231

160-282. Kinetic Data for the Schmidt Reactions of m - and p-Substituted Benzoic A cids ...... 232-295

283-284. Kinetic Data for the Decomposition of Hydrazoic Acid...... 296

285-310. Kinetic Data for the Effect of Acidity on the Rate of the Schmidt Reaction of o-Toluic Acid,...... 297-318 I. INTRODUCTION

Reaction of hydrazoic acid with a carboxylic acid (the

Schmidt reaction) results in formation of the corresponding amine, carbon dioxide, and nitrogen (Equation 1). In order to

R-COgH + HNs H2SO4 ^ R-NHz + COg + Ng (l) effect this important general reaction it is necessary to use strong mineral acids as catalysts.

Mono-substituted benzenedicarboxylic acids in which the substituent is proximal to one of the carboxylic groups react selectively with one equivalent of hydrazoic acid to give only single mono-substituted amino acids. The novelty and utility of this reaction is that the more #sterically-hindered= carboxyl group is converted to the cor re spending amine. For example,

3-sub stituted phthalic acids or anhydrides in sulfuric acid react at the internal, more hindered, carboxyl group (Equation 2) to

OgH CPzH CO2H + HN3 H2SO4 [I I + CO2 + N^ (2) yield exclusively the corresponding 3-substituted anthranilic acids. Upon reaction of 2- or 2,6 -disubstituted terephthalic acids (Equation 3) the more hindered carboxyl group is also

1 COzH m Î 2 (3) G (G) + HNî H2SO4 _ I I + CO2 + Nz

COgH CO 2H

selectively replaced. Similarly, the sole products obtained from Schmidt reactions of isophthalic acids which contain sub­

stituents in the 4-position (Equation 4) are the corresponding

COgH COgH (4)

+ HNg HgS 0 4 ^ + COg + Ng

4-sub stituted, 3-aminoben.zoic acids.

Because of the dramatic accelerative influences associated with proximal groups in Schmidt reactions, a study was initiated of the possible mechanisms of these processes. It was decided to determine the influence of structure on the kinetic order, rates, and kinetic parameters of reaction of hydrazoic acid in sulfuric acid with substituted benzoic acids in the following series:

(1 ) ortho-sub stituted benzoic acids, to measure proximity effects on the Schmidt reaction

(2 ) meta- and para-substituted benzoic acids, to determine the electrical requirements of the Schmidt reaction

(3) di- and trimethyl/benzoic acids, to determine possible buttressing and accumulative electrical and proximity factors in the Schmidt reaction

To gain additional insight into fundamental details of the mechanism, a study of the effects of sulfuric acid con­ centration on the rate of the Schmidt reaction of ortho-toluic acid was made. The kinetics of decomposition of hydrazoic acid in concentrated sulfuric acid were also investigated. n. HISTORICAL

The Schmidt Reaction

Reactions of carbonyl compounds with hydrazoic acid in strong acids have become known as Schmidt reactions. These reactions were first discovered by Schmidt on studying the decom­ position of hydrazoic acid by sulfuric acid (1), Acting on the

(1) K, F, Schmidt, Z, angew Chem., 36, 511 (1923). hypothesis that one of the primary decomposition products of hydrazoic acid is imine, NH, which is capable of reacting with an unsaturated group, Schmidt added benzophenone to the reaction mixture. A rapid reaction occurred, and a quantitative yield of benzanilide was obtained (2) (Equation 5). O C> CfiHg-C-C^Hs + HN 3 ------> C6H5-C-NH-C 6H5 + Nz (5)

(2) K, F, Schmidt, Acta Acad, Aboensis, Math. etPhys,, 2, 38 1924, C. A ., 19 , 3248 (1925).

The Schmidt reaction of carboxylic acids in strong mineral acid (Equation 6 and 7) yields amines having one less carbon atom, carbon dioxide and nitrogen; a presumed

4 R-COzH + HNs > RNCO + Ng ( 6 )

R-NCO + HzO — ------> RNHz + COg (7) intermediate is the isocyanate which is subsequently hydrolyzed in the aqueous medium. Aldehydes give nitriies and formyl derivatives of amines, and ketones yield amides, AJdehydes and ketones with excess hydrazoic acid (two or more equiva­ lents) form substituted tetrazoles (Equation 8 ),

RCOR + 2 HN3 H2SO4 RC = N + H2O + Nz (8 )

A more complete description of the scope of the Schmidt reaction has been given by Wolff (3),

(3) H. Wolff in Adams “Organic Reactions, * Vol, III, John Wiley and Sons, Inc,, New York, N, Y ,, 1946, pp, 307-336,

The mechanisms of Schmidt reactions of carbonyl com­ pounds have attracted the attention of certain investigators,

Schmidt proposed that hydrazoic acid is cleaved by strong mineral acid to nitrogen and imine, NH, Ketones or aldehydes undergo addition of imine at the carbonyl group (Equation 9) followed by rearrangement either directly or by a Beckmann- type transformation of an intermediate ox±tne. (4), 6

[RzÇ-OH

RzCO + & * i ( [ '■ : ^ RCONHR (9)

T? o h .

(4) K. F. Schmidt, B er., 5_8 , 2413 (1925).

This mechanism for aldehydes and ketones was criticized by Oliveri-Mandala, who proposed a sequence (Equation 10) involving addition of hydrazoic acid to the carbonyl group

o n + — O** " -Nz\ RzCcO + HN, R zG -l^ N H N : RzC-N: RCONHR (10) EL followed by loss of nitrogen to give an unstable irnino derivative, which rapidly undergoes a Beckmann-type rearrangement o :.' to yield the corresponding amides (5),

(5) E, Oliveri-Mandala, Gazz, chim. ital., 5^, I, 271 (1925).

Hurd attempted to amplify the mechanism by proposing activation of hydrazoic acid by concentrated sulfuric acid ( 6 ).

(6 ) C« D, Hurd in Gilman “Organic Chemistry, ® Vol. I, John Wiley and Sons, Inc., New York, N. Y. 1938, p. 699. 7

Hn N -N = N •• : " H' 2SO4 r . I > HN-N=N;ft (11)' ' Hurd*s mechanism (Equations 12, 13, 14) for reaction of hydrazoic acid with carboxylic acids is

9 “ + ? ¥ + R-C-OH + HN-NSN: R-C-N-NsN; (12) oh”

O H O ^ R-C-N-NsN:I tt > R-Ç-N+ T + «• (13) \ / OH OH

X ¥ R -C -N + ------^ RNH-COOH ^ RNHz + 002,(14) 6 h

The transient intermediate formed by addition of “activated* hydrazoic acid to the carboxylic acid (Equation 12) loses nitrogen to yield an unstable imino derivative (Equation 13), which undergoes rearrangement to the intermediate carbamic acid. Decomposition of the carbamic acid gives the amine and carbon dioxide (Equation 14),

Evidence was soon forthcoming on the structure of azide ions. X-ray (7) and Raman spectral ( 8 ) studies indicate that the

(7) S, B, Hendricks and E. Pauling, J. Am, Chem, Soc., £7, 2904 (1925).

(8 ) A. Langseth and J, R, Nielson, Phys, Rev. , 44, 326 (1933), 8 azide ion is composed of three collinear atoms. The following

structures were proposed for the resonance hybrid ion (7):

:N::N::N: <------> ;NîN:N: (15)

The structure of hydrazoic acid was thus represented as the following resonance hybrid ( 9 );

(9) Li, O, Brockway and L, Pauling, Proc, Natl, Acad. Sci,, 1_9, 860 (1933),

j- "I ^ H ~ N = N = N : <— > H-N—NsN: -<—^ î3UN=N—N; (16)

Briggs and Lyttleton ( 1 0 ), attempting to relate the strength of a carboxylic acid and the rate of its Schmidt reaction,

(10) H, Briggs and W, Lyttleton, J, Chem, Soc,, 421 (1943), carried out a semi-quantitative study on benzoic acid and 14 substituted benzoic acids (Table 1), The reaction rates deter­ mined from the time of evolution of hcilf of the total volume of nitrogen are in the reverse order of the acidities of the carboxylic acids as measured by their dissociation constants in water. The order obtained for decreasing speed of reaction of the meta- subsHtuted acids is -CH^> -H ^ -OCgH^^ -OCH^^ -Br

-I ^ -COgH^ -CN^-NOg, whereas the acid strengths are 9 approximately in the reverse order: -NO^^ -CN^

-Br^ -Cl^ -OCH^ -OCgH^ -CH 3.

T able I a The Schmidt Reaction of Substituted Benzoic Acids (10)

Yield of Recovered V ol. o f Nz Acid Amine, % A cid , % m l. % m in .

m-Chlorobenzoic 75 -- 535 9 5 ,5 12

m-B romobenzoic 72 -- 515 92 10

m-Iodobenzoic 62 32 452 80 15

m-Hydroxybenzoic ^ 80 15 507 91 5

m -M ethoxyb enz oic 77 16 500 89 4

m-Ethoxyb enzoic 73 23 4 9 4 88 4

m-Nitrobenzoic 63 32 432 77 100 c m - Cyanob enz oi c 59 38 404 72 18 c iso-Phthalic 57 40 447 80 17

m -T o lu ic 42 51 448 80 2

B enzoic 69 25 552 98 3

o-Methoxyb enzoic 80 17 558 99 5

£-Methoxyb enzoic 78 17 512 91 1 | o-Nitrobenzoic 68 26 541 96 2 d £-Nitrob enzoic 41 54 385 69 120

H ydrazoic --— 280 50 22 10

^ The aromatic acid and hydrazoic acid (0,025 mole of each) were dissolved in 1 0 0 ml, of freshly purified trichloro- ethylene and equilibrated at 40® + 0,5®, The reaction was started by adding 8 m l. of concentrated sulfuric acid; the kinetic mixture existed as two phases. The authors point out that *this method does not give completely satisfactory results owing to the initial rise in temperature on mixing the reagents®. This is particularly true since more than half of the compounds studied have a half-life of five minutes or less. It should also be noted that the rate of decomposition of hydrazoic acid is much faster than the rates of Schmidt re­ actions of m - or p-nitrobenzoic acids,

^ Since the aminophenol is readily oxidized, the yield of product was estimated from the recovered acid,

^ In these cases, the amine sulphate was not soluble in the sulphuric acid and separated as a sludge in the trichloro- ethylene layer,

^ This acid was not completely soluble in 100 ml, of solvent and the conditions were therefore not standard.

In the mechanism of Briggs and Lyttleton (10) the stage

representing liberation of nitrogen (Equation 17) was pictured as;

R R H O -C -C f ------> H O -C -O + Nz (17) H -N -N sN H-N'*'

In order to bring about loss of nitrogen, the charge on the middle nitrogen atom must be neutralized by transfer of an electron from the rest of the molecule to this atom. It was suggested that if R is nucleophilic, this step will occur rapidly 11

and the rate of evolution of gas will be relatively fast; on the

other hand, if R is electrophilic, the rate of nitrogen evolution

will consequently be relatively slow.

To explain the unpredictably rapid reaction of o-nitro-

benzoic acid, Briggs and Lyttleton suggested the following

scheme: (Equation 18) HO O HO O- “V, (18) NH products fY > o- LI/' ^ +Nz a 6 o r Jaffe subsequently made a conventional Hammett plot of

the results of Briggs and Lyttleton for meta-sub stituted benzoic

acids (11). A rho for the reaction of -1.415 was obtained having

(11) H. H. Jaffe, Chem. Rev., 5_3, 191 (1953).

a standard deviation of 0 , 150 and a correlation coefficient of

0.940. He also found -log k® (calcd.) - 5.289, i.e. the value

of -log k calculated for CT" = 0 .

McEwen and Mehta plotted sigma values versus log tjV t|- for the Briggs and Lyttleton results (12). By the method

(12) W, E. McEwen and N. B. Mehta, J. Am. Chem, Soc., 74, 526 (1952). 12

of least squares they obtained a rho value of -1, 97 (of. Jaffe;

rho = -1,415), The origin of the differences in the results

obtained by Jaffe and by McEwen arid Mehta is not obvious.

Considerable investigation has shown that the migrating

group becomes bonded to nitrogen with retention of configuration (13),

(13) C. K. Ingold, Structure and Mechanism in Organic Chemistry, Cornell University Press, Ithaca, N, Y ., 1953 pp. 500 - 502,

For example, (+)-od-phenylpropionic acid reacts with hydrazoic

acid to yield (-)-o(-phenethylamine in which the initial stereo­

chemistry is at least 99. 6 per cent preserved (14).

(14) A, Campbell and J. Kenyon, J. Chem, Soc,, (1946).

Realization of the importance of proximity factors has allowed considerable insight into the mechanics of the Schmidt

reaction of carboxylic acids. Caronna (15) obtained 3-nitroisatoic

(15) Caronna, Gazz. chim. ital,, 71, 475 (1941), C. A ,, 37, 118 (1943). anhydride (Equation 19) from 3-nitrophthalic and hydrazoic acids in sulfuric acid. 13

+ N 2+H2O (19) I I + HN, HN3 H,SO^H2SO4 _ II I il c = o CO2H ^ / V2 2 NO NO rjr H

Newman and Gildenhom (16) reported that the acid-

(1 6 ) M, S, Newman and H* L, Gildenhom, J. Am, Chem. Soc., 70, 317 (1948).

catalyzed reaction of 2 , 6 -dimethylterephthalic acid with hydrazoic

acid (one equivalent) resulted (unexpectedly) in exclusive replace­

ment of the hindered carboxyl group. These investigators con­

cluded that the specificity of the Schmidt reaction with 2 , 6 -d im eth y l-

terephthalic acid was due to steric strain and electrical factors re­

sulting from the 2 , 6 -dimethyl groups, and they proposed a mech­

anism (Equations 20, 21, 22) for hindered acids involving acid-

R-CO 2H + H2SP4_ RC(0 H) 2 ______^ R C =0 + HzO (20)

9 - - 9 + RC+C+ + ;N-N5N _ R-C-N-N=N (21) à H

R-^-N-fesr ______R -N -C = 0 +Nz HzO RNH3 + COg ( 2 2 ) H H 14

catalyzed activation of the carboxyl group by formation of di-

hydroxycarbonium and then oxocarbonium (acyl) ions. This

postulate arose because of the sim ilarity of this rea.ction to the

estérification of 2, 4;6-trimethylbenzoic (mesitoic) acid in con­

centrated sulfuric acid (l 6 ).

Reaction of hydrazoic acid with carboxylic acids then

proceeds by electrophilic attack of an oxocarbonium ion on

nitrogen (Equation 21) accompanied by rearrangement. The

function of the sulfuric acid is thus to convert the carboxylic

acid to dihydroxy- and oxocarbonium ions (Equation 20). The

oxocarbonium ion attacks the nitrogen atom which is attached to hydrogen in hydrazoic acid (Equation 21). The unstable initial

adduct loses nitrogen as Ng, leaving the remaining nitrogen atom

electronically deficient. This unstable intermediate rearranges j j j by a process in which the organic group originally attached to the carbonyl group migrates to nitrogen. In rearrangement the migrating group carries the pair of electrons which originally bound it to the carbonyl center. The resulting electron-deficient intermediate may then subsequently give carbon dioxide and the amine salt upon reaction with water (Equation 22).

It was also pointed out (l 6) that dihydroxy carbonium ions may react wdth hydrazoic acid in a manner analogous to tliat of 15 oxocarbonium ions (Equations 23, 24, 25):

RCOzH + H2SO4 _ RC(0H)2 (23)

OH . + OH ^ )-C+ + :N-N=N:îjî-N=N —^ HHO-C-N-ISEN O -C -N -N ^HO-Ç+ (24) R H À H

HO-C-N-r^ RNHC(0H)2 + Nz -HzO RNH3 + CO2 (25) R H ^ ^

It was believed however that oxocarbonium ions are more reactive than dihydroxycarbonium ions,

Barkemeyer (17) and Moritsugu (18) investigated the Schmidt

(17) H. R, Barkemeyer, M, S. thesis. The Ohio State University, 1952,

(18) T, Moritsugu, unpublished results. reaction of phthalic anhydride derivatives which contained various electronegative and electropositive substituents in the 3-position.

The only product isolated in each case was that derived by reaction of the relatively hindered (internal) carboxyl group (Equation 26).

COzH HN3 ^ i^^'^NHz (26) H2SO4

G = -OH% -OCH3, -CH 3, -F, -Cl, -COzH, -NOz, -Br, -I, -C 2H5 16

^ The product isolated from the reaction of 3-hydroxy- phthalic anhydride was 2-oxo-4-benzoxazolinecarboxylic acid, COzH CX>-°

This study thus indicates that the electronic character of the substituent is not the predominant factor which contributes to the preferred reactivity of the more hindered carboxyl group,

Barkemeyer also showed that hydrazoic acid did not react with

3-aminophthalic acid, anthranilic acid and m -aminobenzoic acid (present as the amine salts in the reaction media) in 95,5 per cent sulfuric acid at 45 - 50® for 2^ hours (17), The electri­ cal factor is therefore very important when the strongly electron- withdrawing -NH^^ group is present in the reacting molecule.

In subsequent studies Moritsugu found that reaction of

2 , 6 -dibromoterephthalic and 2 , 6 -dinitrotexephthalic acids occurred selectively at the hindered carboxyl position to give

4-amino-3,5-dibromobenzoic (90,79^ yield) and 4-am ino-3,5- dinitrobenzoic (59.2^ yield) acids, respectively (19). 2 , 6 -

Dinitro-g -phenylenediamine (24,5% yield) was also obtained in the reaction of 2 , 6 -dinitroterephthalic acid. 17

(19) T. Moritsugu, Ph, D, dissertatiou, The OMo State University, 1954,

Moritsugu also determined the selectivity of reactions

of 2-sub stituted terephthalic acids and 4-sub stituted isophthalic

acids with hydrazoic acid in concentrated sulfuric acid (19). In the examples listed in Equations 27 and 28 the carboxyl group

CO2H NHz G G HN, (27) H2SO4 CO2H CO2H

COzH CO2 H HNa (28) H2SO4 CO2H

G = -OGH3, -CH 3, -G(CH3)3, -I, -Br, -F, -NOg ortho to the substituent G reacted exclusively. The yields for these reactions ranged from 7 0 to 9 0 p er cent.

In order to determine the electrical effects of substituents in the absence of varying steric effects on the Schmidt reaction, the select!vities of reaction of phthalic acids substituted in the

4-position with various electronegative and electropositive 18

substituents were determined (19) (Equation 29), With, the ortho-

CO2H NHz CO2H C O g H HN3 . I + I (29)

O H2SO4 G G G I n G -OCH3 -CH 3 -C(CH3)3 -Br -F -NOg -COgH

Yield of I (%) 9 2 . 0 72.7 63.0 74.5 87.9

Yield of n (%) - 14.9 15.7 12.6 - 74.6 91.8

para-directing groups, -OCH 3 and F, reaction took place only

at the 1-substituted (para) carboxyl group ( I ). With strongly

electron-attracting (meta-directing) groups, -NOg, -CO ^,

only the 2-sub stituted carboxyl group was replaced ( H ). Mixed isom ers were obtained from the compounds having -CH 3, - 0 (0113)3 and -Br substituents,

Tetrachlorophthalic and 1, 2-naphthalic acids and their anhydrides have been reported to be unreactive to hydrazoic acid in concentrated sulfuric acid (20). The lack of reactivity of these

(20) G. Oaronna, Gazz, chim. ital., 71, 475 (1941).

derivatives has been attributed to steric hindrance ( 2 1 ),

Moritsugu ( 1 8) has subsequently shown that tetrachlorophthalic 19

(21) H. Wolff irt Organic Reactions, Vol. Ill, John Wiley and Sons, Inc., New York, N, Y ,, 1946, p. 307.

anhydride is insoluble in a large excess of 9 6 per cent sulfuric acid. Upon using fuming sulfuric acid as a solvent, tetrachloro­ phthalic anhydride was converted to 2-am ino-3,4, 5, 6 -tetrachloro- benzoic acid in 87.5 per cent yield. Further investigation revealed that 1, 2- and 1, 6 -naphthalic acids (Equations 30 and 31) do react

COzH NHz COzH HNg (30) H2S 0 4

COzH NH,

HN3 (31) HO; H2SO4 ^ HOgC with hydrazoic acid; the products are those derived from exclusive reaction of the more sterically hindered carboxyl group. It is thus apparent that the activating proximity effect is of importance in polynuclear aromatic acids as well as with benzenoid derivatives (2 2 ),

(22) Tetrabromo-, tetxaiodo-, and tetraphenylphthalic anhy­ drides do not give Schmidt reactions in fuming sulfuric acid, A possible explanation of this lack of reactivity will be d isc u sse d laLter. 20

Aromatic amino acids and certain quinoline carboxylic acids (Equation 32, Table 2) will undergo Schmidt reactions

COzH NHz

(32) "H^Ôri30^“'so;r’

T able 2 The Schmidt Reaction of Quinoline carboxylic Acids

Position of Y ield T im e of carboxyl group (9() reaction (hrs. )

2 trace 12^ 3 8 6 .4 10 5 9 0 . 9 2 6 9 8 ,2 2 7 9 0 . 4 1 8 91.2 4

Væry little gas was evolved in this reaction.

if fuming sulfuric acid {30% SO3) is used as solvent. Reactions of 4-aminoisophthalic (Equation 33) and 2-aminote rephthalic

(Equation 34) acids thus gave 2,5-diamino- and 2,4-diamino- benzoic acids in 87, 9 and 82,0 per cent yields, respectively. 21

COzH NHz

HN, (33) CO2H COzH NHz NHz

CO2H CO2H

HN, (34) 0 " CO2H NHz

These are the first examples of reactions of unhindered rather

than hindered carboxyl groups. Since the initial amino acids

are probably present entirely as amine sulfates, the close proximity of the positively charged ammonium substituents

would be expected,to decrease the ease of ionization of adjacent

carboxyl groups to dihydroxy- and oxocarbonium ions,

A study has been made of selectivity of reaction of an aliphatic aromatic dicarboxylic acid. Thus, reaction of homo- terephthaJic acid with hydrazoic acid gave a 91.7 per cent yield of the two isomeric amino acids (l 8 ), Recrystallization gave a

25 per cent yield of p-aminophenylacctic acid ( X ) and a 6 l p er

cent yield of 4-(aminomethyl)-benzoic acid ( H ) (Equation 35),

CO2H NHz COzH HN, H zsg, (35)

Hz 9 H2 OzH COzH I 22

This experiment implies that the rates of reaction of aliphatic

and aromatic acids are of similar magnitude.

Recently Bak followed the kinetics of Schmidt reactions of benzoic and p-toluic acids by measuring the volume of gas produced in a Broasted shaking apparatus (23). The reactions

(23) T. Bak, Acta, Chem, Scand,, 1733 (1954), were conducted in 95,4 per cent HgSO^ at 25° with concentrat­ ions of hydrazoic and benzoic acids of approximately 0, 05M,

The rate constants obtained were 0,198 x 10 ^ 1 ./mole-sec,

( 0 , 01191,/mole-min, ) for benzoic acid and 0,371 x 1 0

1 , / mole-sec, ( 0,02231,/mole-min, ) for p-toluic acid.

It was concluded that if the Hammett equation is followed the reaction must have a ^comparatively great negative rho v a lu e ,#

Bak gave his reason for not determining the rates of reaction of other substituted benzoic acids as #It proved yery difficult to obtain reproducible results, presumably because the substituted acids decomposed in the sulfuric acid solution

(dark color), ® 23

The Curtius Reaction

Rearrangement of acid azides with elimination of nitrogen is known as the Curtius reaction (Equation 36) (24).

RCON3 ------> RNCO + (36)

(24) The scope and limitations of the Curtius reaction have been revieved by P. A, S, Smith in Adams, » Organic Reactions ®, Vol. HI, John Wiley and Sons, Inc. , New York, N. Y., 1946, pp. 3 3 7 - 4 4 9 .

If the acid azide is rearranged in an inert solvent such as benzene or chloroform, the isocyanate can be isolated. In the presence of solvents such as alcohols or water, the inter­ mediate isocyanates react to form urethanes or ureas

(Equation 37).

RCON3 —> RNCO f ROH RNHCO2R 1 HgO ______/ H2O ^ (RNH)2C 0 J H+ or OH- RNH2 (37)

Because of the sim ilarity of Schmidt and Curtius reactions it is of importance to compare their mechanisms. The kinetics of rearrangement of benzazide in various solvents are first order and salt effects are not observed (25). The rate constant.

(25) M, S. Newman, S. H, Lee, Jr., and A. B. Garrett, J. Am. Chem, Soc., 113 (1947). 24 the activation energy and the entropy of activation vary considerably however from solvent to solvent. The reaction is fastest in solvents such as acetic acid or pyridine and slowest in non-polar solvents such as n-heptane and benzene. It has thus been concluded that solvation of the activated complex in these rearrangements is of importance.

Upon realization that the oxocarbonium ion may be an intermediate in the Schmidt reaction of hindered carboxylic acids

(26), it was predicted (16) that the Curtius reaction would be acid-

(26) M, S. Newman, J. Am, Chem, Soc,, 63, 2431 (1941),

catalyzed if the same (or a similar) intermediate,RCONHN 2 + ,is involved in both reactions. Verification of acid-catalysis in

Curtius rearrangements was subsequently demonstrated (27).

(27) R. A. Coleman, M, S, Newman, and A, B. Garrett, J, Am, Chem, Soc., 76, 4534 (1954),

Recently the kinetics of thermal rearrangement of meta- and para-substituted benzazide s in toluene have been determined (28), Unfortunately this study has been made in

(28) y, Yukawa and Y, Tsuno, J. Am, Chem, Soc., 79, 5530 (1957) 25 a temperature range (6 0 - 80°) very close to the isokinetic temperature, (this general subject will be discussed later) and thus the electrical effects of substituents are minimized.

The first-order rate constants at 70,1° and the activation energies of the 13 compounds studied ranged from 0, 00246 min,"^ and

2 9 , 2 kcal,/m ole for m -nitrobenzazide (slowest) to 0,00439 min. and 24, 5 kcal,/m ole for m-methylbenzazide (fastest),

A plot of log kj against Hammett*s sigma values gave a reasonably straight line for meta-substituents but no satisfactory correlation existed for para-substituents. These results were compared with those for decomposition of benzenediazonium salts in an acid medium (29), Upon plotting log k for the Curtius

(29) M , L i, Crossley, R, H, Kienle and 0. H, Benbrook, J, Am, Chem, Soc,, 62, 1400 (1940), reaction versus log k for decomposition of the diazonium salts, a linear relationship was obtained. It was thus concluded that sim ilar deviations from the Hammett equation existed in both reactions. The same type of deviation has been found in de com r- position of phenylazotriphenylmethanes to nitrogen and substituted phenyl and triphenyhnethyl radicals (30), In general, both 26

(30) S, G, Cohen and G, H, Wang, J. Am, Chem, Soc,, 75, 5504 (1953),

electron -releasing and electron-withdrawing substituents in the

para position slow down the Curtius rearrangement and decom­

position of diazonium salts and phenylazotriphenylmethanes

whereas electron-releasing substituents in the meta position

accelerate these reactions.

The explanation given for the decelerative influence of para-substituents in decomposition of the benezenediazonium

salts is; *the mesomeric electron-releasing substituent, for example the p-methoxy group, increases the resonance

contribution of structure II and therefore increases the bond

energy of the carbon-nitrogen bond, which would lead to re­

tardation of the bond fission® (29) (Equation 38), A similar

^ ^N=N: (38)

I n argument has been advanced for the Curtius reaction. The electronic hybridization in a benzazide containing a para- electron-releasing group may have considerable contribution 27

from resonance structure II (Equation 39). Resonance contribu-

— + + — C -N -N =N i q-N=N=N: (39) CH. :Oi tions by electron-releasing para substituents may thus be expected to strengthen (increase the double bond character of) both the carbon-carbon and nitrogen-nitrogen bonds that have to be broken to liberate nitrogen and allow rearrangement to the isocyanate.

If the rate determining step involves liberation of nitrogen (as is generally believed), resonance of the type illustrated should slow down the reaction.

I The rho value of the Hammett plot for Curtius rearrange­ ment of meta-sub stituted benzazide s is approximately -0, 35 (27).

The Los sen(Equation 40) (31, 32) and Hofmann (Equation 41) (33)

R-CONH-OCOR R-CON-OCOR |RCOr^_^ RNCO (40)

(31) W, B. Renfrew, Jr., and C. R. Hausér, J, Am, Chem, Soc,, ^9, 2308 (1937),

(32) R, D. Bright and C, R. Hauser, J, Am, Chem, Soc., 61, 618 (1939), 28

RCONHBr ^ RCONBr ■ [r COn] ----- » RNCO (41) -HgO slow

(33) C. R, Hauser and W, B, Renfrew, Jr. , J. Am, Chem, See,, 59, 121 (1937).

rearrangements have much in common with the Curtius reaction.

The rho value for the Liossen rearrangement is -2, 593 (11).

The electrical requirement indicates that the rate-determining

step involves loss of the carboxylate ion with possible participa­ tion of the migrating group. Similar electrical requirements appear to be involved in the Hofmann rearrangement.

The Hammett Equation

The correlation between the reactivity and structure of compounds is one of the m ost important and intriguing objec­ tives of modern chemistry. Certain progress has been made in this direction by Hammett, who has proposed that there is a

general quantitative relation by which the effects of meta- and para-substituents on. the reactivity of benzene derivatives may be correlated (34, 35), The relation is now known as the 29

(34) L i, p. Hammett, J. Am, Chem, Soc., 96 (1937),

(35) L, P, Hammett, Trans. Faraday Soc,, 156 (1938),

Hammett equation and is usually applied in the form,

log(k/ko) =crp (42) where k and kq are rate or equilibrium constants for reactions of the substituted and the unsub stituted benzenoid compounds, respectively. The substituent constant, cT* , depends solely #n the nature and position of the substituent, and the reaction con­ stant, Ç , depends only on the reaction and the conditions under which it has been effected. Because of the large body of reliable data for ionization of substituted benzoic acids in water at 25^ ,

Hammett selected this reaction as a standard, i.e ., ^ = 1,

The values for (P can thus be determined from the relationship

(T = log(K/Ko) (43) where K and Kg are the ionization constants for substituted and unsub stituted benzoic acids in water at 25°,

The substituent constant

(36) R. W, Taft, Jr,, in M. S. Newman, ed,, Steric Effects in Organic Chemistry, John Wiley and Sons, Inc., New York, N, Y., p. 556 ff.

Jaffa, upon correlating 42, 000 rate and equilibrium constants (3180 reactions) (37), has found that the Hammett

(37) H. H. Jaffe, Chem, Revs., ^3, 191 (1953), equation is followed with a median precision of 15 ^ (35).

It was found by Hammett (38) that two widely different

values are necessary for the p-nitro substituent. The normal

(38) L, P, Hammett, Physical Organic Chemistry, McGraw- Hill Book Co., Inc., New York, N, Y, 1940, p, 184 ff.

O' value obtained from the ionization constant of p-nitrobenzoic acid does not satisfactorily correlate the reactions of aniline and phenol derivatives. The O' value required for the p-nitro substituent in reactions of anilines and phenols,O'" , is belieYed 31 to arise from relatively large resonance interaction as illus­ trated in I and n .

+.NH2

I n

It has since been shown (37) that all substituents in the para position that can accept an electron ( -COOH, -COOR,

-CHO, -COR, -CONH2, -C N , -SO2CH3 ) by resonance inter­ action, have ^ “values as well as normal C para values. The

constants are used when the site of reaction has free p or ir electrons that enter into resonance with the benzene ring (i, e, anilines and phenols).

More recently it has been demonstrated (39» 40) that

(3 9 ) D. E, Pearson, J, F, Baxter and J, C, Martin, J. Org, Chem., ;^7, 1511 (1952),

(40) N* C* DenoandA. Schriesheim, J, Am, Chem. Soc., 77, 3051 ( 1 9 5 5 ). substituents that donate electrons by resonance also have dual

6' values. Reactions that have a deficiency of electrons in the transition state, such as electrophilic aromatic substitution. 32 are best correlated by + values (41, 42%,

(41) H. C. Brown and Y. Okamoto, J, Am, Chem, Soc,, 79, 1913 (1957).

(42) Y, Okamoto and H, C, Brown, J, Org, Chem,, 485 (1957).

^ + values thus appear to correlate the effects of sub­ stituents on nitration of benzenoid derivatives because of stabilization of transition states by resonance interaction as illustrated in UX.

H . NO,

Equilibrium reactions involving an electron-deficient center are also best correlated by ^ values if resonance interaction with the aryl nucleus is important. For example, the ionizations of di- and triarylcarbinols to the corresponding carî)onium ions (Equation 44) are correlated by O' ^ rather than

(S' values (43). 33

OH t CftHs-Ç-CéHs CôHs-C-CôHs C6H5-C-C6H5 H+(-H2 0 ) _ x L r î ^ (44)

(43) N, C. Deno and W. L, Evans, J, Am, Chem, Soc,, 5804 ( 1 9 5 7 ).

An unfortunate complication in attempting CT ^ correla­

tions arises from the fact that no standard reaction for the

determination of the constants has been established and there­

fore many O' values exist for each of the more common

substituents (42),

Acidity Functions

The reactions of carboxylic acids with hydrazoic acid

are catalyzed by concentrated strong acids. It is thus impore- tance to consider the possible roles of the acid on the mechanism

of Schmidt reactions,

Hammett and co-workers have defined an acidity function

which accurately expresses the ability of a given solution to 34 trauQsfer a proton to a neutral base under conditions in which pH or hydrogen-ion concentration lose significance (44, 45).

(44) L i, p. Hammett and A, J, Deyrup, J. Am, Chem. Soc,, 54, 2721 (1932).

(45) Lio P. Hammett, Physical Organic Chemistry, McGraw- Hill Book Co., New York, N. Y ., 1940, p. 267.

This function, Hq, is defined by Equation 45:

Ho = - lo g %i+ (45) ^BH+

Since the ratio, f / f , has the same vcdue for all bases (44), B BH+ the acidity function, Hg, is independent of the base for its measurement and is a characteristic property of the solution.

The strength of a base, B , that is electrically neutral is determined by the acidity constant of its conjugate acid, expressed in terms of activities instead of concentrations

(Equation 47).

B h '*' '■«;. ■ B + H'*' (46)

PKa = - 1“8 %+=bAbH+ (4'')

Upon combining Equations 45 and 47 and using the relationship f = a/c, an alternative expression (Equation 48) for H@ is obtained.

Ho = pKg. + log c g /c g jj^ (48) 35

By starting in dilute aqueous acid where Hg = pH, increasing the acid concentration, and using a series of overlapping indicators from which the ratio, Cg / Cg^^ , can be measured colorimetrically, Hammett and associates determined the Hq function for acids such as sulfuric, nitric, perchloric, hydro­ chloric and trichloroacetic acids (46, 47)» Analogous acidity

(46) L. P, Hammett and M. A. Paul, J. Am, Chem, Soc,, 56, 827 (1934).

(47) L, P. Hammett, Chem, Rev,, l6, 67 (1935), functions have been defined for cationic (Equation 50) and anionic (Equation 52) bases, H- and H+ values may be quite

+ H'*’ BH'^'*' (49)

H+ = " ^ + ^ b +'^^BH++

and b " + H^ ^ BH (51)

H - = (52) different from those of Ho (48),

(48) Hq and related acidity functions have been reviewed comprehensively by M. A. Paul and F, A, Long, Chem. Rev., 57, 1 (1957), 36

The Ho function is of importance in determining the

kinetics and mechanisms of acid-catalyzed reactions. Applica­

tion of acidity functions to reaction kinetics and mechanisms

has been surveyed comprehensively by Long and Paul (49).

(49) F, A, Long and M, A, Paul, Chem. Rev., 935 (1957)

It is known that certain acid-catalyzed reactions are

not correlated by Kg or similar acidity relationships, A

typical example is aromatic nitration in which there is much

independent evidence that the attacking species is a nitronium

ion (NOg^). The mechanism will thus require overall ioniza­

tion of nitric acid with loss of water according to Equation 53,

HONO2 + h'*' NOz^ + H 2O (53)

W estheimer and Kharasch (50) have found that the rate

of nitration of nitrobenzene in 80 - 90 per cent sulfuric acid

(50) F, H ,, Westheimer and M, S, Kharasch, J, Am, Chem, Soc,, 68, 1871 (1946),

does not obey an Hg function but parallels the ionization of tris- ^-nitrophenyl) carbinol (Equation 54) in the same media,

A rjC -O H + H"^ ArjC"^ + H2O (54) 37

It was subsequently shown (51, 52) that conversion of nitric

(51) A, M. Liowen, M, A. Murray and G. Williams, J, Chem, Soc., 3318 (1950).

(52) M. A. Murray and G. Williams, J. Chem. Soc,, 3322 (1950) acid to nitronium ion may also be correlated with ionization

(Equation 54) of various triarylcarbinols in 75 - 85 per cent sulfuric acid.

Gold and Hawes (53) defined an acidity function, Jq ,

(53) V. Gold and B, W, V. Hawes, J. Chem, Soc,, 2102 (1951), for removal of hydroxyl groups from alcohols by Equations

55 and 56. Jo = “PKj^OH " ^ (55)

Jo = - lo g ^ ^ROH (56) a-HjsO %+

By substituting Equation 45 into Equation 56 there is obtained the relationship;

J„ = H„ + loK _ - lo g W ^ROH (57) 38

It was suggested (53) that the last term in Equation 57 may be negligible and that absolute values of Jo can be obtained from the approximations

Jo' = Ho + lo g (58)

It was subsequently shown, however, that the approximation is unsatisfactory at lower acid concentrations, although it is useful for relative Jq values in solutions containing more than

73 per cent sulfuric acid (54),

(54) G. Williams and M, A, Bevan, Chem. and Industry, 171 (1955).

Deno and colleagues (55) have subsequently defined an

(55) N, C. Deno, J, Jaruzelski and A, Schriesheim, J, Am. Chem. Soc., 77, 3044 (1955). acidity function, Co , by Equation 59 in which pKj^+ is the

Co = “ iog ( equilibrium constmt for alcohols and carbonium ions (Equation 60),

+ HzO ' ROH + H+

Co values for mixtures of sulfuric acid and water ranging from

1 to 92 per cent acid were determined by an overlapping indicator 39

method using diaryl- and triarylmethanols. The utility of the

Co function has been demonstrated in correlating the rates of

aromatic nitration (56).

(56) N. C. Deno and R, Stein, J, Am, Chem. Soc., 78, 578 (1956).

Upon comparing Equations 55 and 59 it is apparent

that Co = Jo by definition. Because of the faulty assumption

made by Gold and Hawes, their values for Jq are not accept­

able. A second difficulty in the Jq treatment arises from the

use of concentrated (80 - 95 per cent) sulfuric acid as the

standard state. The Co treatment is of advantage in that dilute

aqueous solution is the standard state.

The Co function has subsequently been found to correi?- late oxidation of formic acid by nitrous acid in aqueous sulfuric

acid (57, 55), This result supports the mechanism, proposed

(57) J, V. L, Long staff and K, Singer, J, Chem, Soc,, 2604, (1954), on other grounds, that NO^, formed reversibly from HNOz,

reacts with formic acid in the rate-determining step. 40

Decarbonylation of triphenylacetic acid (58) in sulfuric

(58) H, R. Dittmar, J, Phys. Chem., 33j 533 (1929)

acid has also been shown to give a linear plot of unit slope

for log k versus Cq (59). This result is consistent with a mechanism in which protonation of triphenylacetic acid produces

(59) N, C. Deno and R. W. Taft Jr., J. Am. Chem, Soc., 76, 244 (1954). the oxocarbonium ion which loses carbon monoxide in the rate- determining step. III. DISCUSSION OF RESULTS

Kinetic Order of the Schmidt Reaction

In the present investigation an independent determina­

tion was made of the kinetic order of reaction of benzoic and

hydrazoic acids in concentrated sulfuric acid (60), The reaction

(60) T, Bak (22) had previously found using gasometric tech­ niques that reactions of benzoic and p-toluic acids with hydra­ zoic acid in 95.4 per cent sulfuric acid occur by second order p r o c e s s e s . was followed by determining the concentration of benzoic acid

at any time by ultraviolet spectrophotometric methods (see

Experimental ), The half-lives of reaction of benzoic acid and hydrazoic acid at equal concentrations were determined from a plot of concentration of benzoic acid versus time.

Typical data for initial concentrations of the reactants and the

resulting half-lives at 47,3® are: 0,10 M, 50 min. ; 0,05 M,

100 min* ; and 0. 02 M, 250 min. The reaction was thence found to be second order ( n=2 ) (61) upon solution of the

(6l) A, A. Frost and R, G, Pearson, Kinetics and Mechanism, John Wiley and Sons, Inc., New York, N.Y. , 1953, p, 41,

41 42

following equation:

n = 1 + Xo^ - logt|- (61) log a - log é?

In a subsequent experiment using a 20-fold excess of sodium

azid e, a p lot of the data a s a fir s t ord er reaction , lo g jc^HgCOgH] versus t, gave straight lines.

The kinetic results thus indicate that reaction of benzoic acid with hydrazoic acid in excess sulfuric acid is indeed a second order process, first order with respect to concentrations of both hydrazoic and benzoic acids. In subsequent studies ( see

Experimental and Appendix ) with the many substituted benzoic acids of the present investigation, it was found general that they obey similar second order kinetics in that satisfactory correla­ tions (straight lines) were obtained from appropriate plots.

Leveling of Solvent

In preliminary kinetic experiments with benzoic acid at 24.4°, plots of reciprocal concentration versus time gave satisfactory linear plots. It was found, however, that the rate constant varied with the concentration of the hydrazoic and benzoic acids present. Typical data illustrating the effect of — 43 concentration of reactants (benzoic acid and sodium azide) on the reaction velocity constant ( 1 ./mole-min. ) are; 0,1 M, k% 0.0162} 0,05 M, kg 0.0179} and 0.02 M, kg 0,0188, This decrease in rate with increase in initial concentration of reagents is attributed to reduction of the concentration of the sulfuric acid by benzoic acid and sodium azide since they both behave as bases

(the reaction product, an amine, is also neutralized by sulfuric acid). This minor complication can in principle be avoided by making appropriate changes in the composition of the sulfuric acid used in each esqperiment} the method however is too cum­ bersome and time-consuming. It was found that effects of chang­ ing the actual composition of sulfuric acid can be satisfactorily minimized by keeping the concentration of reactants as low as conveniently possible. Relative errors within a given series of compounds (for example, meta- and para- substituted benzoic acids) were minimized by effecting reaction with the reagents at identical concentrations.

Decomposition of Hydrazoic Acid

In determining the velocity constants for reactions of hydrazoic acid with m - and p-toluic, p-tert-butylbenzoic and 44

p-fluorobenzoic acids (concentrations, 0. 01 M) at elevated

temperatures, it was found that the kinetic correlations deviated

considerably from linear second order plots (Figure 1), It was believed that these deviations were due either to decomposition

or volatilization of hydrazoic acid ( b .p ., 37® ).

To determine the cause of these deviations, the reaction of m -toluic acid was studied at 50® in open and in sealed Pyrex tubes ( see Experimental ), It was found that the kinetic devia­ tions were essentially the same (Figure 2) in both experiments.

It thus can be concluded that decomposition of hydrazoic acid (62)

(62) Hydrazoic acid is not very volatile in concentrated sulfuric acid at 50® even though its boiling point is 37®, The reason for the involatility of hydrazoic acid is that it is highly protonated in concentrated sulfuric acid. The protonation of hydrazoic acid will be discussed subsequently.

(presumably to hydroxylamine and nitrogen) occurs competitively with the Schmidt reaction.

The rates of decomposition of hydrazoic acid in 95,8 per cent sulfuric acid ( in the absence of carboxylic acid ) were investigated at 40 and 50® , The concentration of hydrazoic acid at any particular time was determined by use of m esitoic 300-

250-

1 C 200

rn - Toluic Acid Gone: 0.01 M Temp: 25% 35® 8 50® 150 Tables: 265, 267 8 270

lOOl 1000 3000 5000 7000 t (min.) Ln

FIGURE I 300

250

C rn-Toluic Acid 200 Cone: 0.01 M Temp: 50® Tobies. 281 a 282

150 O Closed tubes X Open tubes

100 500 750 1000 1250 1500 t (min.)

FIGURE 2 47

acid as an analytical indicator (63)* It was found that de com-

(63) The analytical method was based on the addition of hydra- zoic acid (0*01 M) in 95,8% sulfuric acid at 40 or 50° to an equal volume and concentration of mesitbic acid and sulfuric acid at Oo. The resulting solution was kept at 0° for two hours (under these conditions the half-life of reaction of mesitoic and hydrazoic acids is less than 5 minutes) diluted with water, and then analysed spectrophotometrically for mesitbic acid. The amount of hydra- zoic acid at any time could thus be determined.

position of hydrazoic acid occurs by a first-order process. The

rate constants (Appendix, Tables 283 and 284) and the kinetic

parameters for decomposition are; kj (40°) 4,74 x 10 min,

kj (50°) 1,43 X 10“^min,“^j 17.0 kcal,/mole; and

— 27,2 e,u.

Since hydrazoic acid is lost by first (Decomposition) and

second-order (Schmidt) processes simultaneously, determination

of the rate constants under such conditions becomes extremely

difficult. To avoid complications with carboxylic acids that react

slowly, the initial concentrations of sodium azide and carboxylic acid were increased (0, 05 M) to take advantage of a second-order process in competition with a first-order one. Under these condi­ tions linear second-order plots were obtained for m - and p-sub-

stituted benzoic acids fo.r 35 - 70 per cent reaction (Appendix,

Figures 13 to 17; Tables 160 to 257), 48

Effect of Acidity on the Schmidt Reaction

The kinetics of reaction of substituted benzoic acids with hydrazoic acid in excess sulfuric acid have been shown in this investigation to be second order in general. It was of interest also to study the influence of concentration of sulfuric acid on the rates and mechanism of these reactions, A study was there­ fore made of the kinetics of reaction of o-toluic and hydrazoic acids at 24,3° in 71,6 - 97 per cent sulfuric acid,

A possible general mechanism for the Schmidt reaction involves attack of a dihydroxycarbonium ion by hydrazoic acid

(Equation 63) followed by loss of nitrogen and subsequent

RCO;}H + ^------RCOzH/ (fast) (62)

R + HN3 ^ product (slow) (63) rearrangement. If such a mechanism is being followed the reactions should obey the Hq acidity function, A plot of the log of the reaction velocity constants of o-toluic acid versus the Hg values of sulfuric acid should lead to a linear correla­ tion of unit slope.

An alternate possibility is that (64) the mechanism of

Schmidt reaction of carboxylic acids involves attack of an 49

(64) The present discussion is only intended to include the two important general types of acid-catalysis on the various mechanistic possibilities. oxocarbonium ion by hydrazoic acid. If such a mechanism were followed, the kinetics should show an acidity correla­ tion of the Co type. The correlation is derived in the particular case since it is not obvious.

Liet it be assumed that the mechanism of the Schmidt reaction for o-toluic acid involves an oxocarbonium ion

(Equations 64 - 6 6 ) and represents the transition state for

RCOzH + H+ — ^ RG(0 H)2'^ (fast) (64)

RC(0 H)2'*' RCO'*' + HzO (fast) (65)

RCO^ + HN3 —— ^ M"*" product (slow) ( 6 6 ) reaction of the oxocarbonium ion with hydrazoic acid. The activity of dihydroxycarbonium ion is related to the equilibrium constant, K, for ionization (Equation 64) by Equation 67,

^RC(OH)/ = ^COzH (67) K

Assuming that carboxylic acids behave as normal Hammett indicators (Equation 64), the concentration of dihydroxycarbonium 50

ion is given by Equation 6 8 ,

[ r C (O H )/] = [ r COzh] a^+ ^RCOgH ^ = [ r COzh"] hp (68)

^ ^RC(0 H)2 ^

The activity of oxocarbonium ion is related to the

equilibrium constant, K*, for ionization (Equation 69) by Equation 70 (65).

(65) The same result is obtained if prior ionization to dihydroxy­ carbonium ion is considered.

RCOzH + H'*’ RCO'*' + HgO (69)

“ ^ C O zH (70)

If ^RCOzH /^RCO*’ = ^ROH /^R^ in which ROH is a di- or triarylcarbinol (the C@ indicators of Deno et al), then the con­ centration of oxocarbonium ion is ezqpressed by;

r +1 = [RCOzHI ^RCOzH = [ r COzH^ Cq

% 0 ^RCO"^

The overall stoichiometric concentration of carboxylic acid

QiCOzh] 0 in sulfuric acid is

[rCOzhI 0 = [rC O zH ] + [RC(OH)2^ + [rCO"^ (72) 51

Conabining Equations 6 8 , 71 and 72 gives;

[rCOzH] 0 = [rCOzH] ( 1 + ho + Cp ) (73) K K»

The rate equations (Bronsted) for the mechanism postulated are;

" I’ ^RCO,H V / % o V in which f, + is the activity coefficient of the transition state. M Upon relating activities in Equation 75 to concentrations and activity coefficients. Equation 76 is obtained.

rate = k* [rCOzH] [ h n D 5 É . ^RCOaH W 3 (76) K ' a , . _ f ^ ^HzO

S in ce the com position of ^RCOgH d iffers as does

^ROH /^R^ , it i s a ssu m ed that,

^RCOzH W 3 /V = ^ROH/^r"^. (77)

Equation 76 may be transformed to;

rate = k' [rCOzH] [hN^ ^ ^ROH (78) "HrO V and thus, since . Co = %_ ROH , (79) ^ , 0 ^R"*" 52 the rate of reaction may be expressed as

rate = -do = k* [kCOgHl [ h NsI Cq (80) dt K* w h ere Cq = - log Cq • (81)

The experinaentally determined rate coefficient kg satisfies the equation;

kg = - d c / d t = k* Ir COzH ] Ph NsH C q (82) gCOgH Jo [HN3J0 K* [RCpgHjr l& Jo

By combining Equations 73 and 82 and assuming (for the present) that the hydrazoic acid is unprotonated (ie, QiNgJ = ^HNgJo )

Equation 83 is obtained,

kg = _k* ______Co K» /l + ^ + £oT (83) \ K K»y in which h© /K and Co /K * relate the amounts of dihydroxy- and oxocarbonium ions respectively. If the carboxylic acid is present in solution essentially unprotonated (ie, hg^^C and

Cq^ ^ K * ), Equation 83 reduces to:

kg = k* Co , (84) K'

log kg = log Co + log k* = -Co + log k* (85) K* K*

It may be concluded therefore, if reaction of o^-tolviic acid with 53

hydrazoic acid involves the o%ocarbonium ion and if the o-toluic

acid is present predominantly in its unprotonated form, a plot

of log kg versus -C q will he linear and have unit slope.

When the kinetic results for reaction of o-toluic and

hydrazoic acids in sulfuric acid of various concentrations

(Table 3) are plotted against H q (Figure 3), a partially curved

line is obtained in which the slope of the linear portion is equal

to 1.5, A similar curve is obtained when the correlation is

attempted with Co values of sulfuric acid; the plot is linear

over a concentration range for sulfuric acid of 71 - 80 per cent

and has a slope of 0,75 (Figure 4), The kinetic behaviour for

o-toluic acid is thus not satisfactorily correlated by the simple

Ho and C@ functions that have been presented.

The ionization constant for the conjugate acid of hydra­

zoic acid has been recently determined (Equations 8 6 and 87) ( 6 6 ),

HîNî''’ HNj + H'*’ (86)

(6 6 ) T, A, Bak and E, L. Praestgaard, Acta, Chem, Scand, , n , 901 (1957), 54

0.0

- 0 4

M - 0.8

- 1.2 Slope = 1.5

- 1.6

- 2.0

FIGURE 3

0.0

-0.4

- 0.8 o» o

- 1.2 Slope = 0.75

- 1.6

-20 18 20 -Co FIGURE 4 55

It thus becomes apparent that hydrazoic acid is highly protonated

in concentrated sulfuric acid, and the degree of protonation will

be quite varied over the concentration range of the sulfuric acid

used for the previous and Cq correlations. In order to attempt

correlation of the kinetic behaviour of o-toluic acid with acidity

functions, it is necessary to determine the effective concentra­

tion of hydrazoic acid in each experimental system.

Equation 89, which relates K + (Equation 88) to hq H2N 3 may be derived

= ^ 2N3^ (8 8 )

Kz = [hNsI V W 3 ^ hq jHzNs^] [HgNri

The concentration of is expressed by IHzN^ "I = iHNa jq (90) - Q i N ^ where QlNa^ is the concentration of unprotonated hydrazoic acid in solution and Q^N^jq represents the total of unprotonated and protonated hydrazoic acid. Combination of

Equations 89 and 90 gives

Kg = [m hq (91) - M 56

which, when solved for results in:

[ h Ns^ o = Fh NsT (ho + Kz) (92) Kz

Upon combining Equations 82 and 92 the rate constant k 2 is

expressed by Equation 93

î m n Kz Co V (93) p y (Kg + ho)

Upon assuming that the carboxylic acid is predominantly present

unprotonated, Equations 94 and 95 are obtained:

= k: Kz Co (94) K« (K z + h o )

log kz = - Co - log (Kg + ho) - pKz + pK + log k* (95)

A p lot of log kz v ersu s - Cq - log (Kz + ho) should be linear

and have unit slope if reaction of o-toluic acid with hydrazoic

acid involves the intermediate oxocarbonium ion and unprotonated hydrazoic acid.

It was found that, upon plotting the rate constants of

o-toluic acid against -Co - log (Kz + ho) , a straight line

(Figure 5) was obtained having a slope of 1, 0 over a range of

sulphuric acid from 71 - 83 per cent. Over the concentration 57 +0.41-

0.0

- 0 4

- 0.8 o» Slope = 1.0 - - 1.2

- 1.6

- 2.0 6 8 97 10 ■Go - log (Kg + hg) FIGURE 5

+ 0 4

0.0

-0.4

- 0.8 O' o _ - - 1.2 Slope = 1.0

- 1.6

-4 -Co-log{hoh+ + K3(K2+ho)} FIGURE 6 58

range indicated the result is in satisfactory agreement for a

reaction mechanism involving proton transfer to o-toluic acid

and loss of water to give the corresponding oxocarbonium ion.

At concentrations of sulfuric acid above 83 per cent there is

considerable deviation from the theoretical linear relationship

of unit slope. Upon making an appropriate Hq treatment in which

protonation of hydrazoic acid is considered, the correlation

obtained is poorer than that previously obtained for a simple

Hq correlation.

Attempts to improve the correlation involving formation

of the oxocarbonium ion of o-toluic acid have been made in the

following manner. It has been previously reported (67) that

(67) A. Hantzch, B er,, 6_3, 1782 (1930).

the i-factor of hydrazoic acid in sulfuric acid is 2. 3 - 2 , 7 . (68 ).

(6 8 ) The * i * - factor is the apparent number of particles formed from a reagent dissolved in an ionizing solvent as determined by cryoscopie methods.

It is thus apparent that there is an appreciable concentration

of diprotonated as well as monoprotonated hydrazoic acid at 59

the melting point (approximately IQO) of 100 per cent sulfuric

acid. Although the i-factor for hydrazoic acid may be some­

what in error, the pK^ has been estimated to be 10,1 (6 6 ),

An equation of the C q type may be derived as follows

to include the effects of hydrazoic acid which is diprotonated.

K3 = ^ (96 )

Since protonation of to should obey an h+ function,

[H 3N3+ + I

and [HaNa*'^ = [H zN ^H h+ (98) K3

Substituting for from Equation 89 gives:

= [hn{] ho h+ , (99 ) K2K3

The total concentration, 0 » of hydrazoic acid in sulfuric

acid at any time is

[hnJo = [HN3] + + [ h 3N3'^ ^ (1 0 0 ) 60

Combination of Equations 89» 99 and 100 gives;

[H N Q o = [ h Ns] / i + ho + boh+ (101) Kz K2K3 ,

Equation 102 is obtained from Equations 82 and 101 and the assumption .. that the carboxylic acid is unprotonated.

, k* _cg ______= K* ( 1 + ho + ) (102) Kz K2K3

k: Co Kz K3 (103) K* (K 3 (Kz 4 ho) + hoh+ )

log kz = -Cq - log ( hoh+ + K 3 ( Kz + ho ) + con st, (l 04)

It has been shovm. that H+ is parallel to Ho in fuming sulfuric acid (69). An equation indicating the relationship

(69 ) J. C. D. Brand, W, C. Homing and M. B. Thonxley, J. Chem. Soc., 1374 (1952).

betw een Hq and H+ was derived (69) (Equation 105),

H+ = Ho - 0 .2 8 (105)

On the assumption that the previous relationship holds in the region of 71 to 97 percent sulfuric acid and using the value

10,1 for pKs , the terms in Equation 104 were calculated 61

(Table 3) and plotted (Figure 6), The resulting correlation

(F igure 6 ) is a slight improvement over that obtained in Figure 3 but deviation from a straight line of unit slope is still consider­ able for concentrations of sulfuric acid above 83 per cent.

The previous attempts to correlate the kinetics of re­ action of o-toluic acid have been made on the basis that the effective concentration, , of the carboxylic acid is equal to its stoichiometric concentration, j^RCOjH^o * and that the effective concentration is insensitive to the change in con­ centration of the sulfuric acid. Since such assumptions appear unjustified, a general treatment of the kinetic effects arising from protonation of o-toluic acid has been made. Upon com­ bining Equations 73, 82 and 101 a general expression is ob­ tained (Equation 106) which relates the e^erim entally

k. = K. / i + ^V. V + _cp\/i+hp \ . 1.. 4.+ \T (1«6) \ K Kz K2K3; observed velocity constant to actual unprotonated o-toluic and hydrazoic acids. The logarithmic form of Equation IO 6 is;

log kg = -Co - lo g ( KK* + K* hy t K Co ) (107) - log ( K .^ 3 + K3I10 + hoh+ ) + con st. T able 3

Acidity Functions and Rate Constants for £-Toluic Acid at 24,3

“6 -Ho -Co h(pclO -C o-log -Co-log(hoh+ kg log (Kg+ho) +K3(K2+ho) )

9 7 .0 9 .1 4 18. 94 1380 9 .8 0 -0 . 38 2.91 + 0 .4 6

9 5 .8 8 . 94 1 8 .3 6 871 9 .4 2 -0 .7 3 2 .4 7 ^ + 0 .3 9

8 9 .2 8 .1 6 1 6 .5 2 1 4 4 .5 8 . 36 -1.75 1.51 +0.18

' 8 5 .7 7 .7 3 15.61 5 3 .7 7 .8 7 - 2 .2 4 1 .1 1 6 + 0 .0 5

8 2 .8 7 .3 4 1 4 .8 8 2 1 .8 8 7.51 -2 .5 9 0 .7 4 0 - 0 .1 3

80.1 6 .9 8 1 4 .1 9 9 .5 5 7 .1 9 -2 .9 1 0.3 6 7 - 0 .4 4

77 .1 6 .5 7 13. 38 3 .7 2 6 .6 5 -3 ,4 5 0.1030 - 0 .9 9

7 4 .4 6 .2 2 1 2 .6 8 1 .6 6 6 .1 6 -3 .9 4 0 .0 3 1 4 -1 .5 0

7 3 ,8 6 .1 4 12. 54 1 .3 8 6. 06 -4 . 04 0 .0 2 6 0 - 1 .5 8 ON tM 7 1 ,6 5 .8 5 11 .9 5 0.71 5 .5 8 -4.52 0.00875 - 2 .0 6

Calculated from the equation; = kT A s '^ '/r A n t ' K T 63

Since the pK* ( P^j^q(oH) 2^ ) o-toluic acid has not been

determined, direct correlation of the observed rate constants

cannot be made on the basis of Equation 107, By trial and

error it was found that a pK* of approximately -7, 6 g iv es a

satisfactory linear relationship of observed rate constants

over the range of sulfuric acid investigated (71.6 - 97 per

cent) ( see Appendix, Figure 37 ).

The ionization constant, pK*, of the conjugate acid of benzoic acid (C^Hs(OH)^) in sulfuric acid is -7,38 (48), On

the basis of the inductive effects of a methyl group it might be predicted that the pK* for o^-toluic acid will be smaller than

-7,38, On the other hand, steric factors will tend to decrease the stability of the conjugate acid of oi-toluic acid. Since it has been found that o-alkylbenzoic acids are stronger than benzoic acid in water, it appears that steric influences have greater effects than do electrical factors under these conditions, o^-Toluic acid may be weaker base than benzoic acid in sulfuric acid and a pK* ( pKgy+ ) of -7, 6 for o-toluic acid is reasonable.

Confirmation of the present treatment must await experimental determination of the actual pK* of jo-toluic acid.

Even though a very satisfactory correlation may be made on the basis that the for o^-toluic acid is -7, 6 , a 64

complete fit should perhaps not be expected in view of the be­

haviour of aromatic compounds in concentrated sulfuric acid.

For example, the solubilities of oxygen-containing aromatic

compounds in sulfuric acid increase more rapidly than do their

protonations (70) in 70 - 90 per cent sulfuric acid. Hammett

(70) L, P. Hammett, Physical Organic Chemistry, McGraw- Hill Book Company, Inc., New York, N. Y ,, 1940, p. 273.

states that ®obviously sulfuric acid may dissolve these sub­

stances by virtue of some other property than that of convert­

ing them to their conjugate acids, ®

There is much evidence that sulfuric acid will react

with the pi electron system of an aromatic nucleus, linear

correlations between log k% and -H q have been obtained from

the kinetics of exchange of isotopic hydrogen in aromatic com­ pounds in aqueous acids (71), The results have been interpreted

(71) V, Gold and D. P. N. Satchell, J. Chem, Soc,, 2743 (1956).

as involving a rate-determining exchange reaction in which there is intramolecular rearrangement of a protonated form of the aromatic compound. This mechanism was airq>lified by 65

the postulate that the entering proton is attached to the aromatic

nucleus as an “outer complex® in which it is bonded less firmly

(perhaps by ir bonding) than the deuterium atom to be replaced.

Decarboxylation of 2,4, 6 -triaJLkylbenzoic acids (72), and

(72) W, M. Schubert, J. Donohue and J, D. Gardner, J. Am, Chem, Soc., 76, 9 (1954),

de carbonylations of 2,4, 6 -trialkylbenzaldehydes (73) have

(73) W, M, Schubert and R. E, Zabler, J, Am, Chem, Soc,, 7_6, 1 (1954),

maximuun rate constants in 80 - 90 per cent sulfuric acid.

Similarly, nitrations of aromatic compounds have maximum

rates in 89 - 93 per cent sulfuric acid (74), The nitration

(74) R, J, Gillespie and D, J, Millen, Quart, Revs., 2 , 277 (1948),

results have been explained upon assuming that the formation of nitronium ion is essentially complete in 90 per cent sulfuric acid (Equation 108), The decrease in rate in higher concentrations

HONOg + NO^ + HzO (108) of sulfuric acid is presumably due to protonation of substituents 66

and formation of ir complexes of the aromatic compounds.

It has been stated (23) that the reacting species in

Schmidt reactions of quinones is diprotonated hydrazoic acid

The correlations of the present investigation show

that the only species that gives any measurable reaction with

o^-toluic acid is free hydrazoic acid (HN 3). The results of the

present study also may be interpreted to indicate that o-toluic acid ( i-factor = 2 ) reacts by way of its oxocarbonium ion. An

alternative mechanism, reaction of dihydroxycarbonium ion with hydrazoic acid followed by loss of water prior to a rate determin­

ing step, is improbable for other reasons and will be discussed la te r .

Attempts to study the effects of concentration of sulfuric acid (below 83 per cent) on the rates of Schmidt reactions of benzoic or m- or substituted benzoic acids were thwarted because of their low reactivities and solubilities and the relatively

rapid rate of decomposition of hydrazoic acid. To make this desir­ able study it will be necessary ( 1) to determine the Hq and Co acid­ ity functions for a different solvent system such as sulfuric acid- trifluoroacetic anhydride, or (2 ) to extend the present treatment to sulfuric acid of higher concentration. 67

Proximity Effects

In order to (1) determine the causes and magnitude of

the accelerative proximity effects in Schmidt reactions and

(2 ) obtain additional information concerning the possible import­

ance of oxocarbonium ions in these processes, a study has been

made of the kinetics of reaction of hydrazoic acid with 15 ortho-

substituted benzoic acids (Table 4) in 95. 8 per cent sulfuric acid.

The reactions were effected as second-order processes ( first

order with respect to carboxylic and hydrazoic acids, respec­ tively ) in sulfuric acid as solvent. Rate constants were deter­ mined at several temperatures in the range 0 - 40® , kinetic parameters (Table 5) were obtained for most of these systems.

The relative rates of reaction of the benzoic acids at 0® are

compared in Table 4, Data for individual e 3q>eriments and average deviations of the velocity constants are compiled in the Appendix; actual methods are described in the Experimental

S ectio n ,

It has been found that either electron-donating or electron* withdrawing substituents in the ^-position with the exception of fluorine ( minor deceleration ) increase the rates of reaction with respect to benzoic acid. The general order of magnitudes Table 4

Rate Constants for Reaction of Hydrazoic Acid with Substituted Benzoic Acids in 95, 8 per cent Sulfuric Acid

( kz , 1 , / m. -min, )

Temperature, ®

Substituent 0® 10° 20° 25° 30° 40° Relative Rates (0°)

None 0,00697 0 ,0246 0,081 1 o-»Methyl- 0 ,1 2 6 0 .4 5 9 1 ,5 6 300 o -E th y l- 1 .0 4 3 .2 4 8 ,8 0 753 o-Iaopropyl- 0 ,9 6 3 .0 9 8 , 64 2 ,2 6 0 o -tert-Butyl~ 6 .7 6 2 1 .8 6 0 .1 1 5 ,9 0 0 2, 5-Dimethyl- 0 .5 7 5 1 ,8 2 5 ,4 5 388 2, 4 -D im eth y l- 0 .5 3 5 1.71 358 2, 3-Dimethyl- 3 ,0 9 8 .8 0 2 1 .9 2 ,3 1 0 2, 6 -D im eth y l- 12 ,3 28 ,9 0 0 2 , 4 , 6-Trimethyl- 4 9 .6 117,000 o -fT u o ro - 0.00532 0 .0 2 0 2 0,0695 0,6 5 9 o -C h lo ro - 0, 0495 0,1917 0, 362 0. 647 2 8 ,8 o -B x o m o - 0,1 0 5 0 ,3 7 8 0 .7 0 0 1 ,3 0 6 0 ,2 o-J.odo- 0 .4 4 8 1 .5 2 2 ,5 6 4 .3 6 295 o -N itr o - 0.0094 0,0321 0, 0610 0.1009 5 ,9 4 o-Carboxyi- 0,00149 0,00572 0 ,2 2 2 o CO T able 4 (continued)

Temperature,

Substituent 2 0 “ 30® 40® 50® Relative Rates(0®)

None 0 ,00697 0.0246 0,081 1 m -M eth yl 0 ,0 1 1 4 0 . 0409 0 ,1 2 7 0 ,3 8 3 1 ,7 3 ^ -M ethyl 0 .01045 0 ,0367 0,1192 1 ,5 3 m-tert-Butyl- 0 ,0 4 6 2 0 ,145 2 .1 7 p -te rt-Butyl" 0.01155 0 .0 3 9 8 0 ,1 2 3 4 1 ,6 0 m -F lu o r o - 0 ,00595 0,0192 0 ,0 6 0 9 0 .2 2 0 P^-Fluoro- 0.0123 0,0411 0 ,1 3 7 0 ,3 9 9 m -C h lo ro - 0 ,00627 0.0208 0 ,0672 0 ,2 2 0 P^-Chloro- 0,00324 0,01235 0,0419 0 .4 0 7 m -B r o m o - 0 .00646 0 .0 2 2 4 0 ,0 7 7 4 0 ,197 m -M eth oxy- 0 .0 0 7 5 0.0300 0.252 (Hydrazoic Acid) 0,000474 0 ,00143

^ For compounds which were not studied at 0® the rate constants were calculated from the

equation: _ kT S / R -A h^ / rt h vO b , _ , —t . ( kj , mm, ) 70

of th.e accelerative influences indicates dramatically the impor­

tance of proximity (mostly steric) effects (75) in these reactions.

(75) The total range in rate constants for the o~, m -, and 2" substituted benzoic acids of the present study (Table 4) is approximately 600, 000, The maximum ratio in rates (m-tert- butylbenzoic and m-bromobenzoic acids) due to electrical effects in the m - and p- compounds studied is only 11. If steric factors are neglected and the electrical effects of o- and p- methyl groups are assumed to be equal and additive, the result­ ing relative rate^of reaction of m esitoic acid to benzoic acid is predicted to be 3,58} the actual value is 117,000 however.

The results can be accommodated in general by mechanism

sequences (Equations 109 - 113) involving rate-determining

(1) reaction of oxocarbonium ion with hydrazoic ncid (Equation 111)

or (2) decomposition of protonated benzazide (Equation 113),

(76) The results of the present investigation are interpreted in general on the basis that the rate-determining step involves decomposition of the protonated benzazide. Arguments will be presented which support but do not prove this point of view. The general interpretations that w ill be given will not be chang­ ed greatly if the rate-determining step is actual attack of hydra­ zoic acid on the oxocarbonium ion.

+ COzH fa s t. 1+ ^ ^ II J ("9) 71

è o

fa st + H20 (110) East

■h CO

+ HN3 slow products (111)

or + GO CONH-N2 ^ Z + HN3 fa st, (112) "^ast

CONHN2 Z 0 slow ^ products (113)

In reactions of o^-halo and o^-alkyl derivatives respec­ tively, there appears to be general qualitative correlation of the rate constants with the effective sizes of groups ( I ^ B r ^

01^ Fj _t-butyl^^-propyl^ ethyl^ methyl ). The greater

1 0® reactivity of 2 , 3-dimethylbenzoic acid ( kg 3. 09 ) than of

10® 2, 5-dimethylbenzoic acid ( kg 0,575 ) is indicative of steric influences arising from buttressing effects. Electrical effects 72 of G-substituents play important roles; ( electron-donating groups are accelerating; electron-withdrawing are decelerat­ ing ) however, upon comparison with results obtained with analogous m - and p-acids (see subsequent section ), such influences are of lesser significance than are proximity effects.

Derivatives of benzoic acid containing methyl ( electron-donat­ ing ) groups in o, o(-positions such as 2 , 6 -dimethyl- and 2,4,6- trimethylbenzoic acids are even more reactive than is o-tert- butylbenzoic acid.

The enthalpies or energies of activation ( Table 5 ) have been found in general to decrease with increased proximity effects,

Thus reactions of widely differing acids such as o^-iodo, o-nitro, and ^-toluic acids have more favorable enthalpies of activation than do benzoic and o-fluorobenzoic acids. The entropies of activation cannot be correlated as simply however.

Electricad Effects

The rate constants of the present study for reactions of hydrazoic and various m - and substituted benzoic acids in 95, 8 per cent sulfuric acid are summarized in Table 4.

The velocity constants were determined at several tempera- 73

tares in the remge 0 - 50°, The reactions were also conducted

as second-order processes and followed by ultraviolet spectro-

photometric methods. Average deviations and specific data for

individual runs are compiled in the Appendix; the techniques

are described in the Experimental Section, The kinetic para­

meters obtained are listed in Table 5.

m - and p-Alkylbenzoic acids react more rapidly where­

as m-methoxy and m- and g^-halobenzoic acids are less reactive than is benzoic acid. In the absence of steric factors electron-

donating groups accelerate whereas electron-withdrawing sub­

stituents decelerate Schmidt reactions. Electrical effects of

substituents on the enthalpies or energies of activation of m-

and 2 ^-substituted benzoic acids ( Table 5 ) are small but regular.

An electron-donating substituent decreases the enthalpy and

energy of activation; an electron-withdrawing substituent increases these quantities. The average enthalpy of activation for electron-donating substituents ( m- and and m- and

P^-C(CH3)3 ) is 21,3 kcal./ m, and for electron-withdrawing sub­

stituents ( m- andg^-F, m - and Cl, m - Br, and m - OCH 3 ) i s 2 2 ,8 kcal,/m , ( cf, benzoic acid, Ah^ = 21,7 kcal./m , ).

Molecules containing highly electron-withdrawing groups 74

Table 5

Activation Parameters for Reaction of Hydrazoic Acid with Substituted Benzoic Acids,

A A s ^ A f "^ E a

A cid k ca l. e .u . k ca l. k cal. m ole m ole m ole (30®) (30®)

^ -T o lu ic 1 9 .2 - 0 .2 5 1 9 .3 1 9 .8 o-Hthylb enzoic 17.7 -3.95 1 8 .9 1 8 .3 £ -1 sop ropylb enzoi c 1 7 .0 -4 .2 8 1 8 .3 1 7 .6 o-te rt- Butylb enzoic 1 6 .9 - 0 . 72 1 7 .2 1 7 .5 £-Fluorobenzoic 2 2 .8 + 0 .8 2 2 2 .6 2 3 .4 o-Chlorobenzoic 2 1 ,2 + 2 .6 3 2 0 .5 2 1 .9 £-Bromob enzoic 2 0 .9 + 2 ,7 6 2 0 .1 2 1 .5 £-Iodobenzoic 1 9 .0 - 0 .9 5 1 9 .3 19. 6 £-N itr ob enzoic 1 9 .8 —6 . 03 2 1 .6 2 0 .4 2 , 5-Dimethylbenzoic 18.6 -2.08 19.2 19.2 2, 3-Dimethylbenzoic 1 6 .7 -5 .4 1 1 8 .3 1 7 .3 2 ,4-DimethyIbenzoic 1 8 .6 -2 .0 7 19 .3 1 9 .2 B en zoic 2 1 .7 -2 .3 7 2 2 .5 2 2 .3 m -T oIuic 2 1 .3 -2 .7 9 2 2 .2 2 1 .9 £ -T o lu ic 2 1 .5 - 2 .2 0 2 2 .2 2 2 .2 m -te rt-Butylb enzoic 2 0 .9 - 3 . 76 2 2 .1 2 1 .5 £-te rt-Butylb enzoic 21.7 -1 .6 0 2 2 .2 2 2 .3 m-Fluorob enzoic 2 2 .2 - 3 .8 7 2 3 ,3 2 2 .7 p-Fluorobenzoic 2 2 .8 -0 .1 8 2 2 .9 . 2 3 .4 m- GMorobenzoic 22.5 -2 .7 0 2 3 .3 2 3 .1 g^-Cblo rob enzoic 22.7 -0.47 2 2 .9 2 3 .3 m-Bromobenzoic 2 3 .3 -0 .0 9 2 3 .3 2 3 .9 m- Methoxybenzoic 2 3 .4 +0. 92 23.1 2 4 .0 Phthalic Anhydride 23 .1 -0 .7 5 2 3 .3 2 3 .7 75

( m- andp-NOzî m- and ) could not be studied because

of their limited solubilities, complications arising from com­

petitive decomposition of hydrazoic acid and difficulties in effect­

ing methods of analysis.

A correlation of the magnitude of the electrical effects

of substituents was made with the Hammett equation using the procedures of Jaffe (37), A plot of log kg versus Hammett

sigma values is illustrated in Figure 7. m-Methoxybenzoic

acid deviates considerably from the observed linear relation­

ships. Since this deviation possibly arises from solvent-solute interaction such as protonation of the methoxyl group, m-methoxy- benzoic acid was not included in the correlation procedures (77),

(77) A similar Hammett deviation was obtained for alkoxy groups in deterinining substituent effects in protonation of substituted acetophenones and benzoic acids in concentrated sulfuric acid; R, Stewart and K, Yates, Abstracts, American Chemical Society, San Francisco, Calif., 40N (1958),

Benzoic and the five m-substituted benzoic acids

( Figure 7, solid line ) were found to have a Y rho of -1,773 j- 0.060 with a correlation coefficient (r) of 0. 993 and a standard deviation (s) of experiment al points from the plotted line of 0, 032,

When the jp-substituted benzoic acids are included in the overall 76

-1.3 ^ >»m-C(CH3)3

— p(m) = -1.773 ±0.060 • p - C H 3 \ — p(m and p) = -1.538 ± 0.094 -1.5

o -1.7 S

CM

o* o

-19 • p-F f p-CI

- 2.1 • m-OCH

-2.3 - 0 1 0.0 +0 .1 +0.2 +0.3 +04 6

FIGURE 7 77 correlation ( Figure 7, broken line ), ^ = -1* 538 i 0. 094 with r = 0. 964 and s = 0, 065.

A more precise equation to correlate electrical effects in the Schmidt reaction can be derived from Equation 106,

Upon setting k*/K* = kg* ( the rate constant for the reactants as neutral species ) Equation 114 is obtained:

, , cq______2 / 1 + hp + Cp \ / 1 + hp + hph+ \ (114) V K K*; V K; K 2K3 /

In order to compare reactions of various acids run under identical conditions of temperature and concentration of sulfuric acid Equation 114 can be reduced to Equation 115:

1 + ^ + Co (115) K K* where the constant. A, = — ...... (H ^) 1 + ^ + hphf Kg K 2K3

Using the Hammett equation in the form,

log kg* = + log ko* , (117) and substituting for kg* from Equation 115 gives Equation 118:

log kg = (T p - log ( 1+ho + Co ) + log kg (118) K K*

w here k

Since the oxocarbonium ions from m- and substituted benzoic acids are relatively unstable in 95, 8 per cent sulfuric

acid ( the i-factors of these acids in 100 per cent sulfuric acid

are 2 or less ), Cg/K’^^^l and Equation 118 reduces to

Equation 119:

log kz = - log ^1 + hoj + log ko (119)

If the term, ho / K ( the ratio of dihydroxycarbonium ion to un- protonated acid ), approximates zero, the usual Hammett equation ( Equation 117 ) is obtained. If ho /K remains constant for the compounds studied, the Hammett equation will again be satisfied ( the last two terms in Equation 119 will combine into one constant term ). Since it has been shown (77) that benzoic acids containing para-electron-donating substituents are stronger bases than 0^ values predict ( i, e ,, a partial 0 ^ ^ correlation ), the ho /K ratios for these compounds will be larger than those calculated on a ^ basis. Because the second term on the right in Equation 119 is negative, any increase in its absolute value will lead to de celer ative (negative) deviations from the Hammett plot. Reference to Figure 7 indicates that the negative deviations are obtained for g-m ethyl-, p-te rt-butyl and p-fLuorobenzoic acids.

The rate constants for Schmidt reactions of 2, 5-dimethyl- benzoic (meta) and 2 , 4-dimethylbenzoic (para) acids were determined 79 in order to find whether the de celer ative Hammett effect of a para electron donating group (methyl) is of importance in other systems (the ortho substituent is kept constant). The relative rates found ( Table 4 ) for 2, 5-dimethylbenzoic and

2, 4-dimethylbenzoic acids at 0° upon comparison to benzoic acid are 388 and 358, respectively. Since the relative rates and (T' values for Schmidt reactions of m - andg^-toluic acids are 1,73, -0, 069 and 1, 53, -0, 170, respectively, it is apparent that negative Hammett deviations associated with p-methyl groups

(electron-donating) are also of importance in systems which exhibit proximity effects,

A free energy (Hammett) correlation of a complex re­ action (involving equilibrium processes prior to a rate-determin­ ing step) reflects differences only in initial (ground) and rate- determining transition states. Since the initial states for the reactions of meta- and para-substituted benzoic acids are pre­ dominantly ( 92 - 98 per cent ) dihydroxycarbonium ions in

95.8 per cent sulfuric acid (see subsequent section on Kinetic

Parameters), a consideration of the experimentally-determined

p value and negative deviations for + substituents should give certain insight into the. position and nature of the transition state involved in the rate-determining step. 80

In principle the kinetics which have been observed for

Schmidt reactions can be fitted into an overall sequence in which the rate-determining step involves ( 1 ) attack of oxo­ carbonium ion by hydrazoic acid to give protonated benzazide or (2) decomposition of protonated benzazide into products.

The general requirements of the transition state involved in rate-controlling reaction of oxocarbonium ion and hydrazoic acid may be analyzed as follows (Equation 120),

+ :Nz

or (120)

If the transition state ( Structure 1 ) involves minimal initial interaction with hydrazoic acid ( the energy content is sim i­ lar to reactants ), it will be esqiected to have a large amount of oxo* carbonium ion character. Resonance effects involving substituents should thus be expected to be more important in the transition state than in the ground state ( dihydroxycarbonium ion ) (78),

It is therefore to be predicted that positive Hammett deviations 81

(78) Smaller resonance effects are expected in the ground state because the positive charge on a dihydroxycarbonium ion is highly dispersed by delocalization involving the oxygen p-electrons whereas resonance interaction of this type in oxo­ carbonium ions will be minimal. will occur with (S^ substituents; negative deviations are observed however. If bond formation is fairly complete

(Structure II) in the transition state involving oxocarbonium ion and hydrazoic acid (i, e ., the transition state is similar to protonated benzazide), the electrical demand from a m- or g*-substituent in the transition state should be less than that in the dihydroxycarbonium ion. If such electrical require­ ments are involved, the reaction should exhibit a positive value for ^ , the experimental value obtained however is -1, 77.

A similar but a generally acceptable analysis may be made for the overall reaction (from dihydroxycarbonium ion) on the basis that the rate-determining step involves decom­ position of protonated benzazide (Structure III, Equation 121).

HO. + Ov ^NH-----Nz

(121)

in 82

This sequence is in agreement with the experimentai fact that

an overall (T correlation is obtained in that resonance inter­

action of the positive center with the benzene ring will be pre­

dicted to be non-existent in the transition state. The overall

negative deviations obtained for (T "^-substituents thus result

from increased stabilization of the ground state (dihydroxy­

carbonium ions) as discussed previously. Much of the driving

force associated with rearrangement involves formation of nitrogen. Participation of the migrating aryl nucleus (dotted

arrow) will be expected to be relatively minor if the gi electrons

of the aromatic ring are involved; if such participation were

relatively important, positive deviations for (S' ^-substituents would be expected because of increased resonance effects as illustrated in Structure IV.

IV 83

The size and sign found for p (-1,77) also may be

rationalized on the basis of rate-determining decomposition of protonated benzazide. Consideration of the electrical requirements of the initial (dihydroxycarbonium ion) and the transition (Structure IV) states does not lead to an obvious conclusion as to which state has the greater electrical require­ ment, The various electronegative and resonance aspects of the initial and the transition states however lead to the general prediction that their electrical requirements will be similar.

The fact that the observed p is small at temperatures consider­ ably below the isokinetic temperature of reaction (see subsequent discussion) is in agreement with that expected.

The observed greater electrical requirement in the transi­ tion state may be possibly associated with the fact that nitrogen

(and the oxygen in the alternate resonance structure) has a sextet of electrons (Structure V) as well as formal positive charge ;

H

—--N 2 c

VI 84 the benzylic carbonium center of the ground state, however, is highly hybridized by the p-electrons of the two hydroxyl oxygens

(Structure VI). Additional components which may lead to an over­ all negative p are possibly derived from the contribution of un- protonated carboxylic acid to the initial state (the m - and £-acids are only 91 - 98 per cent protonated in the sulfuric acid; the pro­ tonation reaction involves a negative p ) and participation of the sigma electrons of the migrating phenyl nucleus in the transition state.

Activation Parameters

It is often possible to obtain important information with respect to a reaction mechanism by analyzing and correlating the activation ( kinetic ) parameters of the processes. An attempt will thus be made at present to interpret in detail the activation parameters obtained for Schmidt reaction of o_-, m -, and 2 ^-substituted benzoic acids.

It is to be expected that the rate constants and activation parameters of the present study will partly reflect the equilibrium conversions of the various carboxylic acids to their dihydroxy and oxocarbonium ions (79), In order to assess these effects, 85

(79) The rate constants and parameters will also reflect the equilibrium protonations of hydrazoic acid. These effects will remain constant however since the reactions are carried out in sulfuric acid of equal concentrations,

an equation involving A f may be used,

A f ^ = -RTln kz + RTln kt , (122)

in which k and h are Boltzmann and Planck constants respectively.

Upon substituting from Equation 116 for the observed rate constant,

kg , there is obtained

d: A F = -RT In kg: + RT In (I + ho + Cg) + RT In kT , (123) K K* Ah

If the amounts of dihydroxy- and oxo carb onium ions at equilib­

rium are very small (i.e, ho/K and Cq /K* = O), the second

term on the right side of Equation 123 becomes zero. Since

kz* = r .- r (124) .. [R C O ziy Q iNsJ

=|: A F is equal to the difference in free energy between unpro-

tonated carboxylic and hydrazoic acids and the transition state. 86

If the amount of dihydroxycarbonium ion at equilibrium is large (i.e. h g ^ ^ K), Equation 123 reduces to

A F ^ = - r t In K + RT In kT . (125) ho Ah

Upon substituting the value for kg* from Equation 124 and using the relationship,

_ GtCOzâl ho (126) ^ - |ac(OH)/j

Equation 125 is transformed to

AF^ = - RT la p 4? / _ -, + RT In kT [r C(OH)2+^ [HN jJ Z h

Equation 127 can be written as

Ar^ = -RTln kg** + RTIn^ (128) Ah where kg** = . , ,49 / 4^, , ^ (129) [RC(OH)2^ J Lh n J

The initial (ground) state for A F under these conditions is now the dihydroxycarbonium ion and not the unprotonated carboxylic acid. For intermediate cases in which appreciable amounts of both dihydroxycarbonium ion and free acid are present in the reaction 87

medium, the energy level of the ground state will reflect the

equilibrium situation éind lie between the extremes for unpro­ tonated acid and dihydroxycarbonium ion.

By the same procedure Equations 130, 131 relating the free energy of activation to the rate constant kg*** for a reaction involving a stable oxocarbonium ion intermediate are derived;

A f ^ = - RT In kz*" + RTln:^ (130) Ah

In this case the standard (ground) state for A f ^ ( a n d ^ S ^ ,

A h ^ and Ea ) is the oxocarbonium ion.

It is of interest to assess the differences in the enthalpies of activation of reactions of the o-alkylbenzoic acids in which the steric requirements of the alkyl groups are increased.

The differences in A h ^ ( A A H ^) between the ortho-alkyl benzoic acids and a reference state ( A h =21,7 kcal. / mole for benzoic and p-tert-butylbenzoic acids ) are -CH 3, -2 . 5;

-C^Hg, -4. O5 -CH(CH3)2, -4.7; and -C(CH 3)), -4.8. The AAH^ values thus appear to approach a limiting value of approximately

-4 . 8 kcal. / mole. It is of note that the resonance stabilization 88

between carbonyl and phenyl groups has been estimated to be

4 -6 kcal. (80).

(80) Reference 36, p. 603,

Interpretation of the values is consistent with

the suggestion that the rate-deterroining step involves decom­

position of the protonated benzazide (81). The lowering of

(81) Additional evidence supporting decomposition of pro­ tonated benzazide as the rate-determining step was obtained by adding a chloroform solution of benzazide dropwise to con­ centrated sulfuric acid (stirred) and obtaining fair yields of benzoic acid. When the reaction was run at 0®, gas was not evolved and no aniline was formed. At 40° gas evolved briskly and benzoic acid and aniline were isolated; at this temperature aniline could result from a competing Schmidt reaction.

If loss of nitrogen by decomposition of protonated benza­ zide is the rate-determining step in the Schmidt reaction and the principle of microscopic reversibility is applied to the suggested mechanism, it is predicted that protonation of benza­ zide (assuming identical energy contents of protonated benzazides from direct protonation or as an intermediate in the Schmidt reaction) in the presence of water would result in formation of benzoic acid as the primary product. If attack of hydrazoic acid on the 0X0 carb onium ion were the rate determining step in the Schmidt reaction, direct protination of benzazide should yield aniline, (It is suggested that the *acid-catalyzed* Curtius rearrangment should be investigated as to reaction products. The evolution of nitrogen may possibly have originated from acid-catalyzed decomposition of hydrazoic acid (75®) (l 6) or / and from subsequent Schmidt reactions). 89

A h or Eg. with increasing proximity effects of alkyl groups m aybe attributed primarily to steric strain in the protonated o-alkylbenzazides which results in increased inhibition of resonance (the strain in the protonated o-alkylbenzazides will also be reflected in their parent dihydroxycarbonium ions).

On the assumption that the electrical effects of the alkyl groups will be similar, the lowering of A h can be correlated with the relief in strain in a transition state involving conversion of a °Mndered® protonated benzazide to nitrogen and the conjugate acid of the corresponding isocyanate.

To simplify interpretation of the enthalpies and entropies of activation obtained in this study, possible relationships between these quantities may be considered. One of the best criteria for uniformity of mechanism in reactions in which substituents or solvents are varied is a linear enthalpy-entropy plot (82).

(82) J. E. Leffler, J. Org, Chem., 1202 (1955),

A linear enthalpy-entropy relationship m aybe defined h ^ by A h = A Ho + ^ As (132) in w hich AH q is the intercept (the value of A h c o r r e s­ ponding to A s ^ = O) and usually has no physical significance (82), 90

The free energy of activation determines the rate of a reaction at any temperature and is expressed by + + + A f = A h ' - t A s (133)

Combination of Equations 132 and 133 gives: * $ + A f ' = AHo . (T - p)As (134)

When T = p, A f = AHq , and the rate constants of all compounds in the correlation are the same. Thus (3 is called the isokinetic temperature and Equation 132 the isokinetic relationship,

A plot of the enthalpies and entropies of activation for

Schmidt reactions of various o-, m - and p-substituted benzoic acids in 95. 8 per cent sulfuric acid (Figure 8 ) appears to con­ tain three linear relationships. The upper line (m-halo line) correlates phthalic anhydride and all m-substituted benzoic acids (a total of 4 compounds) studied having f constants greater than 40. 33. The center line (m- and£-line) relates linearly all m- and ^-substituted benzoic acids having constants less than +0.23 and £-nitro and £-fluorobenzoic acids (10 com­ pounds). The lower line ^-line) includes all of the remaining o-substituted benzoic acids (8 compounds) for which kinetic parameters are available with the exception of o-tert-butylbenzoic acid. It is possible that the point for o-tert-butylbenzoic acid m-OCH p-F •o~F m-Q! p-CI m-F 22 0—Cl • o-Br AH

2 0 o-NO. ®o-CH 2,5di

-4 -3 -2 -I AS* FIGURE 8 92 falls on a fourth line or between the third and a fourth line,

A fourth line might be expected to include ortho-substituted benzoic acids, such as mesitoic and 2 ,4 , 6-triethylbenzoic acids, in which there are large proximity effects.

It is of interest that the slopes ( p ) of the and m- and p-lines (Figure 8 ) are the same, within experimental error, and correspond to an isokinetic temperature of approx­ imately 260° ( o^-line, 270°; m - and p-line, 250° ). A possible interpretation of the fact that compounds from either the o^- or p- and m-lines have essentially the same isokinetic tempera­ tures is that reactions of both series involve similar, if not identical, mechanisms. The m-halo line as plotted has an isokinetic temperature of only 15®, The m-halo relationship suffers from the fact that the number of related points which define the line is only three and they are not widely separated

( o-phthalic acid in theory should not be included since it is converted to phthalic anhydride in concentrated sulfuric acid; the anhydride is expected to undergo Schmidt reaction by an Ho process ), Furthermore the experimental errors in determin­ ing the activation parameters for these compounds are the great* est of those investigated. The actual isokinetic temperature 93 for compounds which are related by the m-halo line may thus be considerably greater than the value reported (if the present data are plotted within the reliability of the and A S ^ values, the slope of the m-halo line can be made similar to that of the o- and the m - and p-lines). It is thus believed that ®the different slope® (and isokinetic temperature) of the m-halo line does not indicate a different reaction mechanism but that the requirements for the initial and transition states for compounds of this series are slightly different from those of the other series (see subsequent discussion).

A partial interpretation of the four correlations has been attempted on the basis of the kinetic requirements of the initial state and the rate-determining transition state and assum­ ing that the gross mechanisms of reaction for all compounds are essentially the same. The o^-line (lower line) contains most of the o-substituted benzoic acids of the present study including o-toluic acid, which has been shown to Involve reaction as an oxocarbonium ion. On the basis of the general similarity and the linear relation of the enthalpy and entropy values for 2 - sub­ stituted acids, it is suggested that compounds falling on the o- line (lower line) react by similar mechanisms in Schmidt reactions and involve oxocarbonium ions as intermediates. Perhaps an 94

important aspect of the correlation is that these o-substituted

benzoic acids have similar ionization constants in sulfuric acid

and are present in the reaction medium largely as dihydroxy­

carbonium ions in which there is significant steric inhibition of

resonance. The ground states involved in determining enthalpies

and entropies of activation of this series of compounds will thus

in general, be similar. The kinetic requirements for the rate-

determining transition states of the o-acids will also be expected

to be sim ilar. The actual differences in the enthalpy and entropy

requirements for the series are correlated by the isokinetic

relationships,

The compounds which are incorporated by the m - and p-

(center) line exist in concentrated sulfuric acid largely as

dihydroxycarbonium ions (83), The initial states from which

(83) Calculations based on = -7,38 for benzoic acid (48) and p = 1,47 for ionization of conjugate acids of m - and substituted benzoic acids (77) give the following and per­ centages of dihydroxycarbonium ion in 95 , 8 per cent sulfuric acid respectively; benzoic, -7,38, 97,4% ; m-te rt-butylbenzoic, -7.20, 98,3 % ; £-chlorobehzoic, (

correlation for this series is perhaps expected to be different

from that of the previous ortho acids since the ground states

(dihydroxycarbonium ions) do not involve steric inhibition of

resonance and the rate-determining transition states do not

suffer to the consequences of internal strain arising from o-

substituents (84), The compounds which are included in the

(84) In general the enthalpies for Schmidt reactions of o^-car­ boxylic acids are smaller than that for the corresponding m - and jp-acids. The enthalpy differences may be related to differ» ences in the energies of ground states in these two series. m-halo line (upper line) have significantly greater quantities

of unprotonated carboxylic acid at equilibrium in 95 , 8 p er

cent sulfuric acid (83), The ground states for determining the thermodynamic quantities reflect the intermediate positions between unprotonated and protonated acids and thus in general

are of lower energy content than those of the m- and 2 "s e r ie s .

Compounds ( i-factor = 4 ) which fall on the fourth line that has been postulated are predicted to have initial states with energy contents close to that of oxocarbonium ions.

It is also of interest that in general the entropies for

Schmidt reactions of o-, m -, and ^-substituted benzoic acids are sim ilar. Thus evidence further indicates that the acids 96

undergo reaction by similar mechanisms. The entropy changes

are also quite favorable { - 6 ,0 to +2 , 8 e,u, ) for these

reactions particularly upon considering the complexity { third-

order (pseudo second-order) kinetics and steric requirements )

of the processes involved. Much of the favorable entropy can

be attributed to the fact that two energetic reactant particles

( dihydroxycarbonium ion and hydrazoic acid ) yield water and

a transition state exhibiting partial character of nitrogen and

the intermediate conjugate acid of the isocyanate.

The relatively-favorable entropies are also compatible

with the postulate that a Schmidt reaction involves attack of

hydr azoic acid on an oxocarbonium ion and decomposition of

the subsequent intermediate, rather that reaction of dihydroxy-

carbonium ion with hydr azoic acid and eventual formation of products. In general bimolecular reactions have unfavorable

entropies of activation because their transition states are

Bordered* and thus improbable. Mechanisms involving attack

of a dihydroxy carbonium ion by hydrazoic acid w ill thus be

expected to have relatively unfavorable entropies of activation.

Mechanisms involving reaction of a oxocarbonium ion is preceded by loss of water from the dihydroxycarbonium ion (a favorable

entropy step) and thus are expected to be more probable. IV, EXPERIMENTAL

Preparation and Purification, of Aromatic Acids,

_o-Isopropylbenzoic Acid

(General procedure) p-Isopropylbenzoic acid was brominated *cationicéilly* (85) to give 3-bromo-4-isopropyl- benzoic acid, which upon reaction in situ with hydrazoic acid.

(85) The general procedure of D, H, Derbyshire and W, A. Waters, J. Chem, See., 564, 3694 (I950)j ibid, 78 (1951). yielded 3-bromo-4-isopropylaniline, After the éimine (unisolated) had been diazotized and then deaminated with hypophosphorous acid, the resulting oi-bromoisopropylbenzene was treated with cuprous cyanide to give £-isopropyIbenzonitrile, The crude nitrile was hydrolyzed with potassium hydroxide to o-isopropyl- benzoic acid,

(Experimental details) A mixture of p-isopropylbenzoic acid (328,4 g,, 2 moles) and concentrated sulfuric acid (1000 m l.)

97 98 was stirred for 10 minutes. Bromine (102,7 m l., 1,98 moles) was added in one hour; the mixture was stirred for another hour

(the 3-bromo-4"isopropylbenzoic acid was not isolated) (8 6 ),

(8 6 ) (a) A sample from one of the runs, after being sublimed twice and recrystallized from aqueous ethanol, melted at 149 - 149,5°, lit, ( 86 ) (b) 150 - 151°. (b) M . Filetd and F . C rosa, Gazz. chim, ital,, 21 (l), 29 (1891),

Sodium azide (143 g ,, 2,2 moles) was then added in 4 hours.

After the reaction mixture had been stirred for 2 hours and poured on ice (4000 g, ), cold aqeous sodium nitrate (152 g ,,

2.2 m oles, 0 - 5°, 45 m in,) and then hypophosphorous acid

(3 lb ,, 30%, 6 moles) were added. The mixture was allowed to stand overnight. After the silver bromide had been filtered and washed thoroughly with chloroform, the £Lltrate was extracted with chloroform (3 x 300 m l,). The combined chloroform extracts were concentrated and vacuum-distilled to give o-bromoisopropyl- benzene (131 g,, 0, 66 m o le s, 33% yield) (89); b ,p . 90 - 91°

(15 mm, ), lit. (87) 90° (15 mm, ), ( 8 8 ) 210.3° (760 mm, ).

(87) M, Crawford and F, H, C, Stewart, J, Chem, Soc,, 4443 (1952).

(8 8 ) J, H, Lamneck, Jr., J. Am, Chem, Soc,, 76, 1106 (1954) 99

(89) In another experiment 3-bromo-4-isopropylaniline was obtained in 73% yield by basifying the solution from the Schmidt reaction with sodium hydroxide and extracting the de cantate with chloroform and the silver bromide with acetone. The chloroform and acetone solutions were combined and concentrated.

In the best of several experiments (L, Friedman, unpub­ lished results) 3-bromo^4-isopropylaniline was diazotized and then deaminated with hydrochloric and hypophosphorous acids to yield ^-bromoisopropylbenzene {Sl% yield; overall yield 42^ ), Lower yields were obtained when sulfuric acid was used in the diazotization or when ethanol served as the deaminating agent.

In a typical experiment a stirred mixture of o-bromo- isopropylbenzene (40 g, , 0,2 moles), cuprous cyanide (20 g ,,

0,22 m oles), dimethylformamide (40 m l. ) and pyridine (1,5 m l. ) was refluxed for 24 hours. The resulting mixture was poured into a solution of ferric chloride hexahydrate (60 g , , 0 ,2 2 m o le s), hydrochloric acid (10 m l, ) and water (50 m l.) at 50°, After the warm solution had been extracted with benzene, the combined extract was washed successively with hydrochloric acid (20 %), aqueous sodium hydroxide (10 %) and water. The benzene solution wan dried over anhydrous magnesium sulphate, concentrated and vacuum-distilled to yield ^-isopropylbenzonitrile (27 g ,, 0.186 mole, 93 yield); b.p, 91 - 92° (13 mm,), lit. (90) 243 - 244°.

(90) M. Fileti, Gazz, chim, ital,, 16, 281 (1886). 100

o^-Isopropylbeixzonitrile (11,7 g., 0.08 moles) was re- fluxed with potas siuxa hydroxide (30 g ,, excess), water (25 ml. ) and diethylene glycol (30 m l.) for 3 hours. The mixture was cooled, poured into water, and extracted with ethyl ether. The ether and the alkaline extracts were saved. After the combined ether extract had been dried over magnesium sulfate, filtered, and concentrated, the residue was crystallized from aqueous ethanol to give o-isopropylbenzamide (3. 4 g ., 0. 0208 m oles,

25.992 yield), m .p. 159 - l 6 l®, lit. (90) 153.5®, (91) 155 - 160°.

(91) Li. Gattermann and G. Schmidt, Ann., 244, 52 (1888).

The alkaline extract was acidified with hydrochloric acid and extracted with ethyl ether. The ether extract was dried (magnesium sulfate) and aspirated to give o^-isopropyl- benzoic acid, (9,7 g,, 0,059 moles, 73.4% yield), m .p. 51 -

54®. The o-isopropylbenzoic acid was recrystallized twice

(petroleum ether, 35 - 55®) and sublimed twice to give a constant m .p, of 59,0 - 59,5®, lit. (92) 59,4 - 59,9®, (87)

54®, (93) 51®, (94) 63 - 63,5®, The total yield of products is

99.3% (25,9% + 73,4%). 101

(92) J. F, J. Dippy, S, R« C» Hughes and J, W, Liéixton, J, Chem. Soc,, 1470 (1954),

(93) A. Kothe, Ann., ^ 62 (1888),

(94) W, E, Harvey, Acta, Chem, Scand,, 8, 692 (1954),

o-tert“Butylbenzoic Acid

(from p-tert-butylbenzoic acid) A procedure similar to that devised for synthesis of o^-isopropylbenzoic acid was used. Bromine (51,5 ml, , 1 mole) was added in 45 minutes to a stirred mixture of p-tert-butylbenzoic acid (178,2 g ,, 1 mole), concentrated sulfuric acid (600 ml. ) and silver sulfate (171,5 g .,

0,505 moles) at 5 - 10®, After the cooling bath had been removed and the mixture had stirred for one hour, sodium azide (78 g, ,

1,1 moles) was added in 9 hours. The mixture was poured on ice (4 liters) and stirred; hypophosphorous acid (2 lb ,, 30 %,

4 moles) was added. Sodium nitrite (93 g,, 1,35 moles) dis­ solved in a minimum of water was then added to the cooled stirred mixture (0 - 5®) in 30 minutes. After standing over­ night, the mixture was filtered; the silver bromide and aqueous solutions were washed thoroughly with chloroform. Concentration 102 of the chloroform extracts and distillation of the residue yielded o-bromo-tert-butylbenzene (100 g ,, 0,47 moles, 47% overall yield); b.p. 106 - 107* (15 mm.), lit, (87) 96 - 98* (12 mm,).

A stirred mixture of o-bromo-tert-butylbenzene (88 g .,

0,41 moles), cuprous cyanide (40 g ., 0.44 equivalents), di­ methylformamide (70 m l, ) and pyridine (2. 5 ml. ) was refluxed for 20 hours and then poured into a hot solution of ferric chloride hexahydrate (120 g ., 0.44 taoles), hydrochloric acid (20 m l.) and water (100 m l.). The warm solution was extracted with benzene. The benzene extracts were washed successively with hydrochloric acid (20 %), aqueous sodium hydroxide and water, dried over anhydrous magnesium sulphate and concentrated.

The resulting oil, upon vacuum distillation, gave o-tert-butyl- benzonitrile, (62,5 g ., 0. 392 m oles, 95% yield); b.p. 109 -

110* (15 m m .). The product exhibited strong infrared absorp­ tion for a nitrile group at 4. 6 microns.

A solution of o-tert-butylbenzonitrile (37.5 g ., 0,235 m oles), potasslum hydroxide (25 g.), diethylene glycol (150 m l.) and water (8 ml. ) was refluxed for 4 hours. The resulting

solution was cooled and poured into water and extracted with e&yl ether. The alkaline extract was saved. The ether extract 103 was dried over magnesium sulfate, filtered and concentrated.

The resulting oily solid, upon extraction with petroleum ether

(35 - 55®), gave a crystalline solid and an extract which was

concentrated and distilled to yield o-tert-butylbenzomtrile

(4 ,0 g , , 0,0 2 5 m o le s, 89% con version ), b .p . 105 - 106^ (14 m m .).

The crystalline solid, after recrystallization from aqueous ethanol, gave o-tert-butylbenzamide (34.6 g ,, 0.195 moles, 93% yield) ; m.p, 175.0 - 175,4°,

Anal, Calcd, for CnHigON: N, 7.91; C, 74.61, H, 8.52. Found; N, 8.01; C, 74.41, H, 8.35.

The alkaline extract was acidified with hydrochloric acid and extracted with ethyl ether. The ether extract was dried

(magnesium sulfate) and concentrated but no residue was obtained (95),

(95) Subsequent attempts to prepare o-tert-butylbenzoic acid by alkaline hydrolysis involving extensive heating of either o^- tert-butylbenzonitrile or o-tert-butylbenzamide were unsuccessful.

Saturated aqueous sodium nitrite (26 g ,, 0,38 moles) was added (4 hr,) to a solution of o-te rt-butylb enzamide (33,0 g ,,

0,186 moles) in phosphoric acid (300 m l,, 85% ) at 5 - 10®,

The solution w as heated (60®), then cooled and added to w ater

(300 m l,). The resulting precipitate was filtered and dissolved in dilute aqueous sodium hydroxide. The solution was decolorized 104

with, charcoal, filtered through Celite, acidified with hydro­

chloric acid and filtered to give o-tert-butylbenzoic acid (29.2 g,,

0,164 moles, 88^ yield), m.p. 65,5 - 68.0°, The product was

dissolved in ether, treated with charcoal and filtered. After the

ether had been evaporated, the residue was re crystallized from

petroleum ether (35 - 55® ) at 0° to give pure o-te rt-butylb enzoic

acid (26.3 g., 90^ recovery), m.p, 68,0 - 68,5°; lit, (87)(92)

(96) 68,5®, neut. equiv, (found), 176,6 neut, equiv. (calcd,), 178,2,

(96) J. B, Shoesmith and A. Mackie, J, Chem, Soc,, 2339 (1928 ).

o-te rt-Butylb enz oic Acid

(from Oi-tert-butyltoluene) (97) A mixture of o-tert-

(97) The author is indebted to A, M, Rothrock of the Lewis Flight Propulsion Laboratory, Cleveland, Ohio, for a sample of pure o “te rt-butyltoluene. butyltoluene (14,8 g ,, 0,1 moles), sodium dichromate (75 g ,,

0, 25 m oles) and water (150 m l. ) was shaken in a stainless

steel bomb (450 ml, capacity) at 250® for 20 hours. After the bomb had been cooled and emptied, the product was made basic 105

■with soiiiim hydroxide. The chromic oxide was filtered and

extracted with ethyl ether. The alkaline filtrate was also ex­ tracted with ethyl ether and saved. The combined ether extracts, after having been dried (calcium sulfate), concentrated and dis­ tilled, gave o-tert-butyltoluene (2,5 g ,, 0,017 moles, 83^ con­ version), b.p. 171 - 174°, Lit. (98) 170 - 170,5° (743 mm,),

(98) J, Kozak, Anz, Akad, Wiss, Krakau, 81 (1906); Chem, Zentr., (1), 1787 (1907),

The alkaline filtrate was acidified with hydrochloric acid and extracted with ethyl ether. The ether extract was dried (calcium sulfate) and concentrated; the resulting oil was dissolved in petroleum ether, filtered and cooled to 0° (over­ night), The cold mixture upon filtration gave o-tert-butylbenzoic acid (7,4 g,, 0,05 moles, 60%yield), m,p, 67,2 - 68,0°, The product was sublimed to give pure o-tert-butylbenzoic acid (6,7 g .,

0,045 moles, recovery), white crystals, m,p, 68,2° - 68,5°; lit, (87) (92) ( 96 ) 68,5°, mixed m ,p, with authentic o-tert-butyl- benzoic acid showed no depression, neut, equiv, (found) 177,8, neut, equiv. (calcd,), 178.2, 106

2, 6-Dimethylb enzoic Acid

Aqueous sodium nitrite (28 g, , 0,405 molesj HgO, 80 ml. ) was added (20 min, ) to a mixture of 2, 6-dimethylaniline (48,5 g, ,

0,4 moles) and hydrochloric acid (200 m l, , 6 N ) at o \ The solution was neutralized with aqueous sodium hydroxide (7 N ) and added (30 min«) to a cold (0®) mixture of cuprous cyanide (45 g. ,

0,5 moles), sodium cyanide (49 g. , 1.0 moles), water (300 m l,) and toluene (100 ml, ), The resulting mixture was allowed to stand overnight, then filtered and washed with benzene. The benzene (and toluene) extract was washed with aqueous sodium hydroxide, hydrochloric acid and water and dried over magnes­ ium sulfate. The benzene extract, after concentration and dis­ tillation, gave 2, 6-dimethyIbenzonitrile (34,4 g,, 0,264 moles,

6692 yield), m ,p. 89.5 - 90®, lit. (99) 89 - 90® (53% yield ).

(99) H, C. Brown and M, Grayson, J, Am. Chem, Soc,, 75, 20 (1953).

A solution of 2, 6-dimethylbenzonitrile (15.7 g. , 0,12 moles) in concentrated sulfuric acid (40 m l.) was heated (75 -

80®) for 6 hours (100) (101). The mixture was cooled and poured on ice (lOO g,); the resulting precipitate was filtered. 107

(100) In preliminary experiments it was found that heating below 75® gave essentially no hydrolysis; at 85® there was extensive decarboxylation to m-xylene and possible sulfona­ tion of the ring.

(101) The general procedure of G, Berger andS. C, J. Olivier, E,ec, trav. chim,, 600 (1927), washed with water, dried and re crystallized from benzene to give 2, 6-dimethylbenzamide, (10,7 g ,, 0.082 moles, 68^ yield); m .p. 138 - 139®, lit, (99) 120 - 125® (crude) (67fO? (101)

1 3 8 ,5 - 139® (66),

A solution of 2,6-dimethylbenzamide (10. 0 g ,, 0.067 moles) and phosphoric acid (20 m l., 100%) was heated at 145 -

150* (45 m in,), then cooled and diluted with ice-water (40 m l,), basifLed with aqueous potassium hydroxide and filtered. After the filtrate had been acidified with hydrochloric acid the result­ ing precipitate was filtered, washed with cold water and dried at reduced pressure to give 2, 6-dimethylbenzoic acid ( 6, 8 g, , 0. 045 moles, 68% yield); m ,p, 115 - 116®, lit, (99) 115 - 116® (36% yield), (101) 115-116® (74% yield). A sample of the acid, after re crystallization from petroleum ether (64 - 69*) and from n-heptane, melted at 116, 0 - 116,5®. 108

2, 3~Diinethylbenzoic Acid

A mixture of 1, 2, 3-trimetiiyIbenzene (102) (hemimellitene)

(102) The author is indebted to Dr, K, W, Greenlee for a sample of pure 1,2, 3-trimethylbenzene,

((12,0 g ., 0,1 moles), sodium dichromate (30,0 g,, 0,1 moles),

sodium phosphate (60, 0 g, , 0,435 m oles) and water (150 m l, )

was shaken in a stainless steel bomb (450 m l, capacity) at 250°

for l6 hours. After the bomb had been cooled and emptied the

product was basifLed with sodium hydroxide. The chromic oxide

was filtered and extracted with water and ethyl ether. The com­

bined aqueous extract and alkaline filtrate was extracted with

ethyl ether and saved. The combined ether extracts, after having been dried (calcium sulfate), concentrated and distilled, gave

1, 2, 3-trimethylbenzene (6, 5 g, , 0, 054 m oles, 46%conversion), b,p. 172 - 175°, lit. (103) 171,9 - 172,4° (741.4 m m ,),

(103) Li, I, Smith and Li, J. Spillane, J, Am, Chem. Soc,, 6_2, 2639 (1940).

The alkaline filtrate was acidified with hydrochloric

acid, cooled and filtered. The precipitate, when crystallized 109 from aqueous ethanol, gave 2, S-dimethylbenzoic acid, (1.38 g ,,

0, 0092 moles, 20% yield), light yellow crystals, m .p, 143,5 -

146, 0°.

After the previous product had been dissolved in dilute aqueous sodium hydroxide, the solution was carefully neutralized

(pH = 7) with sulfuric acid (2 N) (the mixture was slightly turbid), treated with activated carbon and filtered. The filtrate was acidi­ fied with hydrochloric acid; the solid was filtered and then sub­ limed to give pure 2, 3-dimethyIbenzoic acid (1.20 g ., 0.0080 m o le s, 87% reco v ery ), m .p,< 1 4 5 .6 - 146 , lit . (104) 145 - 146®,

(104) O, Brunner, H, Hofer and R, Stein, Monatsh 93 (1933),

Purification of Substituted Benzoic Acids

The remaining substituted benzoic acids (not described in the preceding synthetic section used in the kinetic studies) were obtained as commercial or private samples. These acids were reclystallized at least three times (to constant m .p.) from various solvents. The ortho-alkyl- and dimethylbenzoic acids and phthalic anhydride were sublimed just prior to the kinetic experi­ ments. The melting points (found and lit.) and the wave lengths of maximum ultraviolet absorbtion of the acids are summarized in Table 6. 110

Table 6

Physical Constants for the Substituted Benzoic Acids

M .p , A cid found lit. o -T o lu ic 1 0 4 .5 -1 0 5 107 (102) o -Ethylb enzoi c 65,0-65.5 65. 6 ^ o-Isop ropylbenzoic 5 9 .0 -5 9 .5 59.4-59.9 * o - tert-Butylb enz oic 6 8 .5 6 8 .5 ^ o-Fluorob enzoic 122 1 2 6 .5 o-Chlo rob enzoic 141.5-142.0 142 o-Bromobenzoic 149-150 150 o-Iodobenzoic 162 162 o-Nitr ob enzoic 1 4 7 -1 4 7 .5 146-148 2,5 -Dimethylb enzoi c 1 3 3 .5 -1 3 4 134.0-134.4^ 2, 3-Dimethylbenzoic 144.0-144.5 144.5-145. 0 ^ 2, 4-Dimethylbenzoic 1 2 6 .5 -1 2 7 125.0-126.0 ^ 2, 6-Dimethylb enz oic 116.0-116.5 116.3-116.7 * M esito ic 1 5 5 .5 -1 5 6 156.6-157.1 B en zo ic 121.5-122.0 122 m -T o lu ic 1 1 2 -1 1 2 .5 111-113 p-Toluic 180.5-181 181 m -te rt-Butylb enzoic 127.0-127.6 127 p-tert-Butylb enzoic 164.5-165 164 m -Fluorob enz oic 122-123 1 2 3 .6 g^-Fluorobenzoic 183.0-183.7 1 8 2 .6 m -Chlor ob enz oic 158 158 2 -Chlorobenzoic 240-241 243 m-Bromobenzoic 155-156 155 m-Methoxybenzoic 109.4-110.0 110 Phthalic Anhydride 131-132 131.6 a See reference 92;, all other melting points are from Dictionary of Organic Compounds, I, Heilbron ed., Oxford University Press, New York, N, Y ., 1953. I ll

Determination, of the Kinetic Constants

Constant Temperature Baths

Caiorimetric thermometers (0.01^) were used to deter­ mine the temperature of the various baths used in the kinetic experiments. The thermometers were calibrated with a platinum resistance thermometer which had been standardized at 0. 00*

(distilled ice water) and 32. 38* (fusion point of NagSO^ and NagSO^' lOHgO) (105).

(105) T. W. Richards and A. H, Fiske, J, Am, Chem, Soc., 36, 485 (1914).

The constant temperature bath used at approximately

0° was a 4g liter Thermos jar. A temperature of -0.02 H- 0, 01® was maintained in the bath by stirring a slurry of ice and distilled water. Other constant temperatures were obtained in stirred baths (E. H. Sargent and Co, , 8-§ gal, ) each equipped with heaters, cooling coil, thyratron circuit and a mercury thermoregulator.

To maintain a temperature of 10* it was necessary to run the water of the cooling coil through copper coils immersed in an ice-filled Dewar Vessel (20 gal.). The temperatures recorded 112 in the Appendix, the recalibrated temperatures (platinum resist­ ance thermometer) and extreme deviations are: loV 9.98 ± 0.03° J 20°, 20. 02 i 0.01°; 24.3°, 24. 30 i 0.05°;

25°, 25. 00 ±0.02°; 30°, 29.99 ±0.01°; 35°, 35. 04 ±0.02;

400, 40. 02 ± 0.02° ; 50°, 49. 97 ± 0.04° .

Kinetic Procedure

Preliminary attempts to follow the reactions of hydra­ zoic and carboxylic acids by gasometric methods gave erratic results because of the dependence of the rate of evolution of gas

(Ng + COg) on the rate of stirrin g of the k in etic m ixtu re (this dependence is presumably due to the tendency of carbon dioxide to form supersaturated solutions in sulfuric acid). A method was thus developed by which reactions of hydrazoic acid with the car- boxylic acids can be followed by ultraviolet spectrophotometric methods. The important details of the experimented methods used are summarized in subsequent sections.

Sp e ctrophotometric T e chnique s

Prior to kinetic runs the ultraviolet spectra of the car­ boxylic acid to be studied was determined, A solution containing

0, 005000 moles of substituted benzoic acid in concentrated 113 sulfuric acid (100 m l,, 0, 05 M) was prepared by weighing the sample on an analytical chainomatic balance in a glass vial

(5 dram); the sample was transferred to a volumetric flask

(100 m l, ) by rinsing the vial with concentrated sulfuric acid approximately 10 tim es. After the mixture had been stirred thoroughly and diluted with sulfuric acid to a volume of 100 m l,,

- 5 a one ml, aliquot was diluted to one liter (5x10 M) with dis­ tilled water. The remaining solution of the sample was treated with 0,1 - 0,2 moles of sodium azide and allowed to stand over­ night at room temperature (since m - and substituted benzoic acids react slowly, treatment was repeated 2 - 3 times at 2 day intervals). The solution which had been treated with sodium I azide to give the corresponding amine was also diluted (1/ 1000,

5 x 1 0 “^ M ),

The ultraviolet absorption spectra (Appendix, Figures

19 to 36) of both aqueous solutions were determined in a Beck­ man DU Spectrophotometer using silica cells (one cm, light path). Since the Schmidt reaction for most of the m - and £- substituted benzoic acids did not go to completion under the conditions described, the spectra of the corresponding anilines

(freshly-distilled commercial samples) were determined independently (Appendix, Figures 19 to 36), 114

The molecular extinction coefficients, E, were calculated from the relationship:

A = E cl (135). in which A is the absorbance (optical density, log (Iq/I) )» c is the concentration (m oles/liter) and 1 is the path length (cm ,).

For substituted benzoic acids that have absorption spectra con­ siderably different from that of the corresponding substituted anilines, the wave length of maximum absorption ( X m a x ,,

Emax, ) of fbe carboxylic acid was chosen for the subsequent analyses. For substituted benzoic acids having molecular extinction coefficients sim ilar in magnitude to those of the corresponding anilines, the wave lengths for the greaitest differ­ ences in extinction coefficients (Eq - E®) between the carboxylic acid and corresponding aniline were chosen for the analyses.

The m ost convenient dilution factors were determined on the basis of the initial concentrations of reactants in the kinetic esqperiments and on the molecular extinction coefficients of the carboxylic acids (Equation 135), (It was desirable to have A q =

0,6 - 1.2, Appendix, Tables 29 - 310), 115

Sulfuric Acid Solutioiis

The sulfuric acid used for all comparable kinetic esperi- ments for substituted benzoic acids was commercial concentrated

C .P , H2SO4, premixed in large quantity before general use.

Analyses of this sulfuric acid did not deviate detectably before or after a blank duplicate run after 2 years of use and storage. The average of all analyses is 95,83 i. 0,02% H 2SO4 , Analyses were effected by titrating samples (0, 20 - 0,25 g, ) of the acid with standardized aqueous sodium hydroxide (0,5 N) to a phenol- phthalein end-point, A micro-burette (0,01 m l,) having a Teflon needle-valve was used for all titrations.

The solution of sulfuric acid used in the study of the effects of acidity on the rates of reaction of jo-toluic acid with hydrazoic acid were prepared by appropriate dilution of commercial concen­ trated sulfuric acid with distilled water and standardization by the previous procedure.

Sodium Azide and Hydrazoic Acid Solutions

Commercial sodium azide (Fisher Scientific Co,} was purified by modification of a previous procedure (IO6), Sodium azide (8 oz,) was dissolved in a minimum of distilled water (90 *) 116

(106) A. W. Browne in •Inorganic Syntheses®, H, S. Booth ed,, McGraw-Hill Book Company, New York, N, Y ,, 1939, l_» p . 79. and filtered while hot, A volume of ethanol (95 %) twice that of the solution was added with stirring, and the mixture was cooled

(0°), The white crystalline precipitate of sodium azide was fil­ tered, washed successively with cold ethanol (100 %) and ethyl ether, dried in a vacuum desiccator, and stored in a brown bottle.

The purified sodium azide was analyzed by visual titration with a standard solution of eerie ammonium sulfate using osmium tetroxide as catalyst (Equation 136),

2 Ce'*"^^'*’ + 2 N3" ------» 2 + 3 Nz (136)

Duplicate determinations indicated that the sodium azide was

99.7 and 99. 8 ^ pure.

Solutions of hydrazoic acid in sulfuric acid were pre­ pared immediately before use in a kinetic run, A sample of sodium azide (exactly 0 ,0 0 2 0 0 0 moles for ortho- and 0 , 01000 moles for meta- and para-substituted benzoic acids) was weighed analytically in a glass vial (5 dram). The sample of sodium azide was quantitatively transferred to a volumetric flask (100 m l . , recalibrated to allow for the volume of a 2 cm. Teflon-coated magnetic stirring-bar) containing cold (0°) 95. 8 ^ sulfuric acid 117

(approximately 20 m l.). The sulfuric acid was stirred magnetic­

ally during the addition of sodium azide. After the contents of

the weighing vial had been rinsed ( 8 - 1 0 times) into the volumetric

flask with 95.8% sulfuric acid, the resulting solution was diluted

to 100 ml. with the sulfuric acid and stirred for 15 minutes.

Solutions of substituted benzoic acids were prepared by the same

p roced u re.

Execution of Kinetic Experiments

The sulfuric acid solutions of hydrazoic and substituted benzoic acids were equilibrated in the bath of the desired temp­

erature (30 min. ). An aliquot (25 ml, ) of the solution contain­ ing sub stituted benzoic acid was introduced into the thermostat- ted reaction cell (a Pyrex test tube, 3 j x 22 cm ., having a nar­ row neck fitted with a polyethylene stopper) by a volumetric- pipette. The same volume (the same pipettes were used for both hydrazoic and substituted benzoic acid solutions to elim ­ inate possible errors in calibration) of the hydrazoic acid solution was added and the time recorded. The solutions were mixed thor­ oughly by shaking. Aliquots were withdrawn by volumetric pipettes, drained (the reaction time was observed during drainage) and diluted with distilled water to the appropriate volume (volumetric flask with 118

glass stoppers). The samples were withdrawn at various inter­ vals according to the velocity of the Schmidt reaction ( 107 ),

(107) The aliquots were drained immediately into volumetric flasks which were approximately half-filled with distilled water and then diluted to volume. For compounds with large dilution factors (i.e., 5-10 m l. H2SO4 ; 50 ml. final volume), the volumetric flasks (half-filled with distilled water) were stored in a deep freeze until the water partly froze. This technique permitted rapid dilution of the sulfuric acid without excessive heating.

Samples could be withdrawn and transferred in 30 seconds.

Recalibrated volumetric pipettes (Exax) were used for sampling.

Because of the high viscosity of concentrated sulfuric acid it was necessary to allow the pipettes to drain for 2 minutes ( 108 )

(108) The same technique was employed in preparing solutions for the measurement of molar extinction coefficients to eliminate possible errors in the final analyses.

instead of the usual 20 seconds (for dilute aqueous solutions).

After every 2 - 3 samples had been withdrawn the re­ action cell was quickly (about 10 sec. ) removed from the constant temperature bath and shaken vigorously by hitting the cell against the palm of the hand. The agitation causes considerable frothing

(depending upon the rate of the reaction) and evolution of gases

(CO2 and N 2) from the reaction mixture. If the *shakin^ is neglected 119 it is impossible to obtain accurate volumetric samples because

of frothing within the pipette. Experiments on duplicate runs

showed that the frequency and number of 'shakings* did not affect the kinetic results as long as the frequency of shaking was suffi­

cient to prevent frothing in the sampling pipettes.

The diluted samples (volumetric flasks) were mixed thor­ oughly and stored (10 - 15 ml, ) in vials (10 dram) with polyethylene

caps. At the end of a run the absorbancies. A, of the samples were determined in the spectrophotometer as outlined previously (109 ),

(109) Cell corrections were made for all analytical runs using distilled water as the blank.

Reciprocal concentrations were calculated from the observed absorbancies (see subsequent section on calculations) and, when plotted against time gave straight lines (second-order plots).

Special techniques were developed to obtain reproducible results for the rapid reactions of m esitoic, 2, 6-dimethylbenzoic and o^-te rt-butylb enzoic acids at 0°, These carboxylic acids

(especially 2, 6-dimethylbenzoic acid) are unstable in concentrated sulfuric acid at room temperature; a solution of 2, 6 -d im eth yl- benzoic acid in sulfuric acid undergoes considerable change even 120 at 0® when stored for fairly short periods. The most probable side reactions are sulfomation, decarboxylation and inter- molecular acylation.

Pure samples of m esitoic and 2, 6-dimethylbenzoic acids were ground to a fine powder (agate mortar), weighed and dissolved in ■ cold (0®) 95.8% sulfuric acid as rapidly as possible. Aliquots of the carboxylic and hydrazoic acid solutions (50 m l.) were trans­ ferred (the pipettes were precooled in a Dry Ice chest) to individual thermostatted Pyrex test tubes (3x15 cm ,). The reaction was started by pouring the contents of each of the tubes into the thermo­ statted reaction cell. (110). The analytical aliquots were withdrawn

(110) This procedure minimized external heating of the viscous (slow draining) reaction solutions during pipetting and errors in estimating the zero time of reaction. with fast-draining pipettes and were ejected forcibly from the pipettes by air pressure from a rubber bulb into precooled dis­ tilled ice-water (see previous description).

In this investigation the reaction solutions did not form dark colors as reported by Bak, (23) as long as the substituted benzoic acids were pure, o-Nitroaniline sulphate resulting from reaction of a o-nitrobenzoic acid with hydrazoic acid was 121 colorless in the reaction medium (95. 8 ^ H2SO4 ) but turned yellow on dilution with water. The diluted samples from this reaction were analyzed both in the visible (410 mu) and in the ultraviolet (229 mu). The results were in good agreement (see

Appendix, Tables 109 - 129).

Reaction of o^-iodobenzoic acid gave colorless solutions, even after infinite time; if excess sodium azide were added to obtain infinite readings sooner, the solution turned black. When the solutions were poured into water a strong odor of iodine was n o ticed .

When the kinetic samples from reaction of phthalic anhy­ dride (111) were analyzed (24 hours after the run was started)

(111) Phthalic acid reacts with concentrated sulfuric acid to form phthalic anhydride. and reciprocal concentrations were calculated (based on an infinite absorption determined from the molar extinction coef­ ficient of anthranilic acid) and plotted against time, curved lines were obtained. It was then observed that the absorption of the solutions were changing (decreasing) with time (112). This phenomenon was believed to arise from formation and subsequent 121a

(112) For example a solution had the following absorptions at the respective times; 0.863, 24 hr. ; 0.850, 48 hr. ; 0.794, 1 m onth.

hydrolysis of isatoic anhydride (Structure I). The solutions

==o

I

were allowed to stand for one month, then reanalyzed (Appendix,

Tables 130 - 135). Plots of the resulting reciprocal concentra­

tions versus time then gave satisfactory straight lines.

Kinetic runs with g^-chlorobenzoic acid were complicated

by the low solubility of unreacted g^-chlorobenzoic acid in water.

The diluted (water) samples had to be heated to approximately

70® to re dis solve unreacted p-chlorobenzoic acid. The solutions

were then cooled, diluted to volume, mixed and analyzed in the

normal manner.

Treatment of Kinetic Data

The experimental data (initial concentrations, tempera­

tures, molar extinction coefficients, dilution factors, absorbancy

4 122

and reciprocal concentrations at times t ) obtained for reactions

of bydrazoic acid with the various substituted benzoic acids are

compiled in the Appendix (Tables 29-310), These data were

treated by the methods to be described to yield satisfactory rate

constants which are summarized in the Appendix (Tables 1-27)

with their average deviations. Calculations were then made of

the enthalpies, entropies and free energies of activation (Table 4),

Rate Constants

The Schmidt reactions investigated were all second-order;

first-order in both carboxylic and hydrazoic acids (113). If the

(113) The reactions are also strongly acid-catalyzed. The catalyst, sulfuric acid, was used in great excess and its con­ centration was practically constant throughout the reaction (see the detailed treatment in the preceding section. Discussion of Results),

initial concentrations of carboxylic and hydrazoic acids are rep­

resented by a and b respectively, if x is the concentration of car-

boxylic acid reacted at tim e t, and if kg is the rate constant, the

integrated kinetic expression (Equation 137) for these second-

order reactions is:

I (137)

! 123

A plot of log versus t gives a straight line with slope equal to kg(a - b)/ 2. 303 , The rate constant kg is calculated from Equation 138;

2.303 slope (138) " (a-b)*^

The data obtained for Schmidt reactions of jo-toluic acid in 74.4 -

89.2 per cent sulfuric acid (Appendix, Tables 285 - 301) were treated according to Equation 137 and gave satisfactory rate con stan ts.

When the concentrations of carboxylic and hydrazoic acids are equal ( a = b ), the integrated kinetic expression

(Equation 139) for the second-order reaction is;

= _ i _ . i (139) a(a-x) a - X a in which ( a - x ) = c (the total concentration of carboxylic acid present in the reaction mixture at time t), A plot of 1/ (a-x),

(1/ c), versus t gives a straight line with slope equal to kg. The reciprocal concentrations are determined from the observed absorbance ( A ) of the carboxylic acid by Equation 140 (see previous section on spectrophotometric techniques);

i = ( Eo - Em ) D (140) c A - Afl)

In Equation 140 Eg and Eg. are the molar extinction coefficients 124

at zero and infinite time (fox meta- and para-substituted benzoic

acids E q, is the molar extinction coefficient of the corresponding

aniline), and D is the dilution factor which converts from analyt­

ical to reaction concentrations. If the products of the reaction do

not absorb light at the analytical wave length ( Ag = O ), the follow­

ing simplified expression (Equation 141) is used,

1 ^ ED (141) c A

The data for reactions of substituted benzoic acids satis­ fied the second-order kinetics of the previous discussion (Tables

29-310). Plots of the appropriate function of concentration versus time gave satisfactory straight lines (for typical examples

see Appendix, Figures 13 - 18),

The decomposition of hydrazoic acid was followed by utilizing its very rapid reaction with mesitoic acid (see previous discussion) and was found to be first-order by the following pro­ cedure, If Co and c are the concentrations of hydrazoic acid at times zero and t respectively, the integrated kinetic expression

(Equation 142) for first-order decomposition of hydrazoic acid is:

kt = 2,303 log ( Co/c ) (142)

A plot of log c versus t gives a straight line with slope = - k/ 2, 303,

The first-order rate constant, k, is determined from the slope 125 and the latter relationship. If the data are plotted as a second- order reaction curved lines are obtained. The experimental data are summarized in the Appendix ( Tables 283 - 284),

Activation Parameters

The activation parameters were calculated from the

“thermodynamic® equation (Equation 143) (6l),

kz = h

where k = Boltzmann constant

h = Planck constant

= entropy of activation

= enthalpy of activation

R = gas constant

and T = absolute temperature.

Equation 143 can be rewritten in the form log (kz/T) = - + AS^ + const. (144) 2.303 RT 2.303 R

Plots were made of log (kg/ T) versus 1 /T (Appendix, Figures

9-12) and A h was calculated from Equation 145:

A h ^ = -2.303 R (slope) (145) 126 * was calculated for each of the temperatures from

(Equation 146); ± ± A s = AH~ ^ 2.303 R log kz - 2.303 R log k (146) T T h or A s ' = Ah + 4.576 log kz -55.36 (147) T T and the average value taken.

Arrhenius activation energies, Ea, ( 30° ) were calculated from the relationship:

Ea = AH^ + R T (148)

Free energies of activation, A F ^ , ( 30° ) were obtained upon solution of Equation 149. ± ± $ Af ' = Ah' - T A s (149 )

The activation parameters obtained in this investigation are summarized in Table 5, APPENDIX

127 128

log

Activation energy plots 1. o -tert -Butvlbenzoic acid 2. g-isopropyl benzoic acid 3. o-Ettiyl ben zoic acid 4. 2,4 - Dim ethyl benzoic acid 5. g-Toluic acid - 4

3.3 3.4 3.6 T 10^ FIGURE 9 129

Activation energy plots I. 2 ,3 -Dimettiylbenzoic acid 2 2 ,5 -Dime thy! benzoic acid 3. s-lodobenzoic acid 4. g-Bromobenzoic acid 5. g-Chiorobenzoic acid 6. g-Nitrobenzoic acid

-2

log ^

-3

“4

3.4 3.5 3.6 Y X 10^ FIGURE 10 130

Activation energy plots 1. m -Tolulc acid 2. g-Toluic acid 3. s -Fluorobenzoic acid 4. £ - Fluorobenzoic acid 5. m ~ Mettioxybenzoic acid €l m-Ghlorobenzoic acid 7. Phthalic anhydride

log ^

FIGURE II 131

Activation energy plots 1. m-tgrt-Butyl benzoic acid 2. D -te rt- Butvlbenzoic acid 3. Benzoic acid 4. p- Chlorobenzoic acid 5. m-Bromobenzoic acid - 3 6. m-Fluorobenzoic acid

log k2

- 4

- 5

31 3.2 3.3 3.4 4" X 10^

FIGURE 12 132

40 -50%

35

1 G

30 Benzoic Acid Table: 165 Cone: Q05M Temp.: 30® kg = 00246 l./ht-min.

25

200 400 600 800 t (min.) FIGURE 13 133

3400 -

3 0 0 0 -

“ 85% 2600

2200 1 C

1800

-7 5 %

1400 Q - tert - Butvlbenzoic Acid Toble: 61 Gone: 0.0025M Temp: 20® kg = 59.2 l/m. -min.

1000

600

0 10 20 30 4 0 t (min.)

FIGURE W 134

6 0 0

500

4 0 0 - -7 5 %

1 C

300

o - lodobenzo ic Acid Table: 99 Gone: 0.01 M Temp: 10* k 2 = 0.450 i./m.-mi n. 200

100 100 300 500 7 0 0 9 0 0 t (min.)

FIG U R E 15 135

40 -50%

35

1 C

30

p -te rt-Butyl benzoic Acid Table: 199 Cone: 0.05 M Temp: 20® k 2 = 0.01146l/m.-min. 25

20 200 1000 1400 1800600 t (min.)

FIGURE 16 136

60

50

C

40 -50%

m - Toluic Acid Table: 177 Gone: 005M Temp: 40® kg « 0.127i./m.-min. 30

20 50 100 150 200 250 300 t (min.) FIGURE 17 137

2 5 0

200 -50%

G

150 o - Chlorobenzoic Acid Table: 77 Gone: 0.01 M Temp: 20“ k_ = 0.1928 l/m.-min.

100 100 200 300 4 0 0 500 600 t (min.) FIGURE 18 138 8 0 0 0 h UV absorption spectra of— g-Toluic acid g- Ethyl benzoic acid g- Isopropyl benzoic acid 6 0 0 0 -

4 0 0 0 -

2000 -

2 4 0 A (mix) FIGURE 19

UV absorption spectra of - o- tert-Butvlbenzoic acid 6 0 0 0 - o- tert - Butvlanil ine

4 0 0 0

E

2 0 0 0 -

2 2 0 240 260 280 300 A (mix) FIGURE 20 139 i20oor UV absorption spectra of - 0 - Fluorobenzoic acid £ -Fluorobenzoic acid

8 0 0 0 -j

4 0 0 0 -

2 4 0 2 6 0 2 8 0 3 0 0 X (mji) FIGURE 21

6 0 0 0 UV absorption spectra of — o-Chlorobenzoic acid o-Ghioroaniline

4 0 0 0 -

E

2000

2 4 0 2 6 0 2 8 0 3 0 0 X (miA) FIGURE 2 2 140

6 0 0 0 UV absorption spectra of — 0 -Bromobenzoic acid o - Bromoaniline

4 0 0 0

E

2000

240 260 280 3 0 0 X (m p.) FIGURE 2 3

12000 - UV absorption spectra of 0 - lodobenzoic acid o- lodoaniline

8 0 0 0 -

4 0 0 0

X (mji) FIGURE 24 141

12000 UV absorption spectra of — 0 - Nitrobenzoic acid 0 - Nitroaniline

8 0 0 0 E

4 0 0 0

2 4 0 280 360 4 0 0

FIGURE 25

8000 UV absorption spectra of — 2,5"’Dimethylbenzoic acid 2,5"‘Dimethylaniline 6000

E 4 0 0 0

2000

— r 2 2 0 240 2 6 0 280 300 X (mu) FIGURE 26 142

12000 UV absorption spectra of — 2,3 -Dimettiylbenzoic acid 2,3“ Dimethylaniline

8 0 0 0

4 0 0 0

220 0 2 6 024 280 300 X (mp) FIGURE 27

12000 UV absorption spectra of — 2,4“Dimethylbenzoic acid 2 ,4 -Dimethylan il ine

8 0 0 0 E

4 0 0 0

2 2 0 240 260 280 3 0 0 X (mp.) FIGURE 28 1.43

12000 UV absorption spectra of — m-Toluic acid m-tert-butyl benzoic acid

8 0 0 0 -

E

4 0 0 0

220 260 280240 300 X (mp.) FIGURE 29

UV absorption spectra of — / y ------2 ” Tolulc acid 12000- \ \ p - tert-Butvlbenzoic acid

8 0 0 0

E

4000

2 2 0 240 260 280 300 X (mu) FIGURE 30 144 12000 UV absorption spectra of — —— m - Chlorobenzoic acid — — m.-Fluorobenzoic acid

8000 E

4 0 0 0

220 240 260 280 300 X (mp.) FIGURE 31

1200C UV absorption spectra of — m- Bromobenzoic acid m.-Bromoaniline

8000

E

4000

220 2 40 260 280 300 X (mp) FIGURE 32 145

I2Ô00 UV absorption spectra of — m-Mettioxy ben zoic acid m-Mett»xyaniline

8 0 0 0 -

4 0 0 0 -

2 2 0 240 260 2 8 0 3 0 0 X (mp) FIGURE 33

12000 UV absorption spectra of - Phttialic ontiydride Anthronilic acid

800

E

4 0 0 0

220 2 4 0 2 8 0 3 0 0

FIGURE 34 146

UV absorption spectra of — 5 0 0 0 - Mesitoic acid 2 , 6 - DimettiyI benzoic acid

3 0 0 0 -

1000 -

220 240 260 280 3 0 0 X (mp.) FIGURE 35

UV absorption spectra of — p- ctilorobenzoic acid 14000- Benzoic acid

10000 E

6 0 0 0

2000

220 240 2 6 0 280 300 X (mp) FIGURE 36 147

+ 0.5

0.0

“0.5

CVJ

- 1.0

- 2.0

-12 II -10 -Co-log{hoh+ + K 3(K2 +h^)} - logfK t h*)

FIGURE 37 148 Table I

Velocity Constants for Reaction of Hydrazoic Acid with o^-Toluic Acid (in 95. 8 % H2SO4, kg*s in 1 ./pi.-m in, )

Temp. 0° 10° 20*

kz 0.126 0.454 1.565 0.126 0.460 1.560 0.462 1.560

k2(av. ) 0.126 0.459 1.56 Av. Dev. + 0.000 + 0. 003 + 0. 002 ■4: Z \h = 1 9 .2 kcal. /mole /S.S = -0. 25 e, u.

Table 2

Velocity Constants for Reaction of Hydrazoic Acid with o-Ethylbenzoic Acid (in 95 . 8 % H2SO4, k.2^s in l./m .-m in. )

Temp. 10* 20* 30° kz 1.035 3.23 8.64 1.045 3. 30 8.80 1.04 3.18 8.96 kz(av. ) 1.04 3.24 8.80 Av, Dev. ± 0.003 ± 0.04 + 0.11

A h'^= 17.7 kcal. /mole A s t = -3. 95 e.u . 149 Table 3

Velocity Constants for Reaction of Hydrazoic Acid with o^-Isopropylbenzoic Acid (in 95. 8 % H2SO4, in 1./m.-min. )

Temp. 0° 10® 20®

kz 0.93 3.10 8 . 68 0.97 3.09 8.76 0.98 3.07 8.48

kz(av. ) 0.96 3.09 8 . 64 Av. Dev. ± 0.02 ■i_ 0.01 + 0.11

A h = 17. 0 kcal./mole A s = -4. 28 e.u.

Table 4

Velocity Constants for Reaction of Hydrazoic Acid with o-tert-Butylbenzoic Acid (in 95.8 % H2SO4, kz*s in 1,/m .-m in.)

Temp. 0“ 10° 20°

kz 6.72 21.7 59.2 6. 87 21.35 59.6 6. 70 22. 4 61.4

kz(av. ) 6.76 2 1 .8 60.1 Av. Dev. + 0.07 + 0 .4 + 0 .6

Ah = 16. 9 kcal./mole As 0.72 e. u. 150 T able 5

Velocity Constants for Reaction of Hydrazoic Acid with o-Fluorobenzoic Acid (in 95.8% H 2SO4, k2*s in l./bi.-min. )

Temp. 20° 30° 40°

kg 0.00539 0.0204 0.0700 0.00528 0.0203 0.0697 0.00530 0.0200 0.0685

k2(av. ) 0. 00532 0. 020 0.0694 Av. Dev. + 0.00004 + 0.0002 + 0.0006

A h = 22. 7 kcal./taole As = -0. 52 e.u.

Table 6

Velocity Constants for Reaction of Hydrazoic Acid with 2 -Chlorobenzoic Acid (in 95.8% H 2SO4, k2*s in l,/m,-min. )

Temp. 10° 20° 30° 40° kz 0.050 0 .1 9 0 0. 360 0. 662 0.0491 0 .1 9 2 8 0.362 0.655 0.1924 0.363 0. 624 kz(av. ) 0.0495 0.1 9 1 7 0.362 0.647 Av. Dev. + 0.0004 0.0012 ± 0.001 + 0.015

A h = 2 1 ,3 kcaJL./mole A s = + 2 . 63 e.u . 151 Table 7

Velocity Constants for Reaction of Hydrazoic Acid with o-Bromobenzoic Acid (in 95,8% H2SO4, k2*s in l./m,-min .)

Temp. 10* 2 0 ° 25° 30°

kz 0.108 0.381 0.694 1.295 0.103 0. 372 0.704 1.345 0. 103 0. 380 0.702 1.25

k2(av. ) 0.105 0. 378 0, 700 1.30 Av. Dev. + 0 . 0 0 2 + 0. 004 + 0.04 + 0.03

A h = 2 0 . 9 kcal./tnole A s = + 2 . 7 6 e. u.

Table 8

Velocity Constants for Reaction of Hydrazoic Acid with o-Iodobenzoic Acid (in 95.8% H ^ 04 , k.2*s in 1 ./tn.-rain. )

Temp. 10° 20° 25° 30°

kz 0.460 1. 51 2.52 4.45 0.434 1.51 2.58 4.25 0.450 1.54 2 .5 9 4.38

kz(a-v. ) 0.448 1.52 2.56 4. 36 Av. Dev. + 0. 009 + 0. 01 + 0.03 + 0.07

A h = 19 . 8 kcal ./mole A s = -0. 95 e. u. 152 Table 9

Velocity Constants for Reaction of Hydrazoic Acid with o^-Nitrobenzoic Acid {A = 410mu) (in 95.8% H2SO4, k2*s in l./m .-m in. )

Temp. 10° 20° 25° 30° k2 0. 00960 0.0322 0.0615 0.1012 0.00935 0.0324 O.O6IO 0.1012 0.00930 0. 0318 0.0605 0.1040 kz(av. ) 0.00942 0.0321 0.0610 0.1021 Av. Dev, + 0.00012 + 0. 0002 + 0.0003 + 0.0012

A h = 19.8 kcal./mole A S = -6, 03 e.u .

Table 10

Velocity Constants for Reaction of Hydrazoic Acid with o^-Nitrobenzoic Acid ( \ - 229mu) (in 95 . 8 % H2SO4, k2*s in l./m.-min.)

Temp.______10^______20^______30° kz 0.0097 0.0334 0.1004 0.0093 0.0334 0.0988 0 .0 0 9 4 0.0326 0.1068 kz(av. ) 0.0095 0.0331 0. 1020 Av. Dev. + 0.0002 + 0.0004 + 0.0032 153 Table 11

Velocity Constants for Reaction of Hydrazoic Acid with Phthalic Anhydride (in 95.8% H 2SO4, kg^s in l./m .-m in.)

Temp. 2 0 “ 30“

0.00153 0. 00600 0.00141 0.00548 0.00152 0. 00568

kz(av. ) 0.00149 0 .00572 Av. Dev. + 0, 00005 + 0.00019

A h = 23.1 kcal./mole A S = -0.75 e.u.

Table 12

Velocity Constants for Reaction of Hydrazoic Acid with 2, 5-Dimethylbenzoic Acid (in 95 . 8 % H2SO4, k|s in l./xi.-min. )

Temp. 10“ 20“ 30“ kz 0.582 1.80 5.43 0.570 1.84 5.45 0. 572 1.815 5.48 k%(av. ) 0,575 1.82 5.45 Av. Dev. + 0.005 ± 0.02 + 0.02

A h = 16. 7 kcal./mole As = -5.41 e.u . 154 T able 13

Velocity Constants for Reaction of Hydrazoic Acid with 2, 3-Dimethylbenzoic Acid (in 95.8% H2SO4, kg's in l./m .-m in.)

Temp. 10® 20° 30®

kz 3.09 8.79 22.2 3.11 8.82 22.2 3.06 8.80 21.2

kz (av. ) 3.09 8.80 21.9 Av. Dev. + 0.02 + 0.01 + 0.4

A h = 16 .7 kcal./nole A S = ■-5.41 e.u.

Table 14

Velocity Constants for Reaction of Hydrazoic Acid with 2, 4-Dimethylbenzoic Acid (in 95 . 8 % H2SO4, kz*s in l./m .-m in.)

Temp. 10® 20®

kz 0.529 1.71 0.532 1.71 0.544 1.71

kz(av. ) 0.535 1.71 Av. Dev. + 0.006 + 0.00

A h = 18. 6 kcal./mole A S = --2. 07 e. u. 155 Table 15

Velocity Constaxits for Reaction of Hydrazoic Acid with Benzoic Acid (in 95, 8 % H2SO4, kg*s in l,/tn ,-m in . )

Temp, 20° 30° 40° kz 0. 00700 0,0244 0,084 0. 00705 0. 0248 0,080 0.00685 0,0246 0,078 kz(av. ) 0.00697 0,0246 0,081 Av, Dev, + 0.00008 + 0,0001 + 0,002

A h =21,7 kcal,/mole AS — ••2,37 e.n.

Table 16

Velocity Constants for Reaction of Hydrazoic Acid with m-Toluic Acid (in 95 , 8 % H2SO4, k2*s in l,/4n,-min,)

Temp, 20° 30° 40° 50° kz 0,0115 0,0412 0.128 0.376 0,01135 0,0408 0.126 0.380 0,0114 0, 0406 0.127 0.3 9 0 0,384 kz(av. ) 0,0114 0, 0409 0.127 0,383 Av, Dev, 0,0001 + 0,0002 + 0.001 + 0,005

A h = 21,3 kcal./mole As = -2, 79 e .u . 156 Table 17

Velocity Constants for Reaction of Hydrazoic Acid with £~Tolnic Acid (in 95. 8 % H2SO4, k2*s in l,/fcn,-min.)

Temp, 20® 30® 40®

kz 0. 01047 0.0368 0.1175 0.01045 0.0370 0.1190 0.01044 0.0363 0.1210

k2(av.) 0.01045 0.0367 0.1192 Av. Dev. + 0.00001 + 0.0003 + 0.0012

A h = 2 1 ,6 kcal./mole As = - 2.2 0 e.u .

Table 18

Velocity Constants for Reaction of Hydrazoic Acid with m-tert-Butylbenzoic Acid (in 95, 8 % H2SO4, k2*s in l./m.-min.)

Temp. 30° 40°

kz 0.0454 0.146 0.0468 0.145 0.0463 0.145

kzXav. ) 0. 0462 0.145 Av. Dev. 0.0005 0, 000

A H = 20. 9 kcal./m ole A S = -3 ,7 6 e.u . 157 Table 19

Velocity Constants for Reaction of Hydrazoic Acid with p-tert-Butylbenzoic Acid (in 95.8% H2SO4, k2*s in l./m .-m in.)

Temp. 20° 30° 40°

kz 0.01164 0,0400 0.1225 0.01146 0.0397 0.1255 0. 01156 0,0397 0.1210

k2(av. ) 0.01155 0,0398 0.1234 Av, Dev, + 0,00006 + 0.0001 + 0.0014

A h =21.7 kcal./mole AS = -1. 60 e.u .

Table 20

Velocity Constants for Reaction of Hydrazoic Acid with m-Fluorobenzoic Acid (in 95 , 8 % H2SO4, k2*s in l./m.-min.)

T emp. 30 40° 50'

0. 00600 0.0197 0.059 0.00590 0.0191 0.061 0. 00596 0.0187 0.0627

k2(av. ) 0.00595 0.0192 0. 0609 Av. Dev. + 0.00004 + 0.0004 + 0.0013

A h = 22. 2 kcal./mole A S = -3. 87 e.u . 158 T able 21

Velocity Constants for Reaction of Hydrazoic Acid with p-Fluorobenzoic Acid (in 95.8% H2SO4, kz*s in l./m .- m in .)

Temp, 30° 40° 50° kz 0,0124 0.0410 0.136 0,0127 0.0414 0.141 0,0119 0,0410 0.135 kz(av. ) 0,0123 0,0411 0.137 Av, Dev, + 0.0003 + 0.0002 + 0.002

A h = 22. 8 kcal,/mole A s = - 0.1 8 e ,u.

Table 22

Velocity Constants for Reaction of Hydrazoic Acid with m-Chlorobenzoic Acid (in 95 , 8 % H2SO4, k2*s in l./fen.-min,)

Temp. 30° 40° 50° kz 0, 00640 0.02080 0.0681 0.00638 0.00205 0.0680 0,00604 0.0210 0.0656 kz(av. ) 0,00627 0.0208 0,0672 Av. Dev, + 0,00016 + 0.0002 + 0.0011

A h = 22,5 kcal./moie A 8 = -2,70 e, .u. 159 T able 23

Velocity Constants for Reaction of Hydrazoic Acid with jp«Chlorobenzoic Acid (in 95, 8 % H2SO4, kg*s in l./in .-m in . )

Temp, 20° 30° 40°

kz 0,00326 0.01284 0.0410 0.00316 0,0120 0,0432 0.00332 0,0124 0,0414

kzCav. ) 0,00324 0,01235 0.0419 Av, Dev, + 0,00006 + 0,00025 + 0.0009

A h =22,7 kcal,/mole As - -0.47 e.u.

Table 24

Velocity Constants for Reaction of Hydrazoic Acid with. m-Bromobenzoic Acid (in 95,8% H2SO4, k2*s in l./ki.-min, )

Temp, 30° 40° 50°

kz 0.00649 0,0219 0,0796 0.00637 0,0220 0,0737 0,00653 0,0232 0,0790

kz(av. ) 0.00646 0.0224 0,0774 Av. Dev, + 0.00006 + 0.0006 + 0.0025

A h = 233 kcal,/mole . As = +0,09 e.u. 160 Table 25

Velocity Constants for Reaction of Hydrazoic Acid with m-Methoxybenzoic Acid (in 95,8% H2SO4, k2*s in 1^ ,- m i n , )

Temp, 30® 40®

kz 0,0075 0.0315 0.0072 0.0285 0.0079 0.0300

kz(a.v.) 0.0075 0,0300 Av, Dev. + 0,0002 + 0.0010

A H = 23, 4 kcal./mole A S = +0, 92 e, u.

Table 26

Velocity Constants for Reaction of Hydrazoic Acid with Mesitoic Acid at 0° C (in 95 . 8 % H2SO4, kz*s in l./n.-m in. )

kz 49,7 50.1 49.1

ka(av, ) 49 , 6 + 0 .4

Table 27

Velocity Constants for Reaction of Hydrazoic Acid with Zf 6-Dimethylbenzoi c Acid at 0® C (in 95 , 8 % H2SO4, kg's in 1,/m,-min, )

kz 12.8 11,6 12.4

kz(av, ) 12.3 + 0,4 T able 28

Velocity Constants for Reaction of Hydrazoic Acid with o^-Toluic Acid (Temp. = 24,3®, k^^s in l./m .-m in, )

(HzS04)% 97.0 89.2 85.7 82,8 80.1 77.1 74.4 73.8 71,6 kz 2,96 1.51 1,127 0,749 0,381 0,1038 0.0313 0, 0264 0,00875 2,80 1.52 1,105 0.732 0,364 0,1019 0,0316 0, 0259 0.00867 2.96 1,51 0.740 0.356 0.1032 0.0313 0,0257 0,00883 kz(av, ) 2,91 1,51 1,1 1 6 0. 740 0.367 0.1030 0,0314 0,0260 0,00875 Av, Dev, +0.07 +0.00 +0.011 +0. 006 +0.009 +0.0007 +0.0001 +0.0003 +0.00005 log kg +0,46 0.18 0,05 -0 .1 3 -0 .4 4 -0 .9 9 -1 .5 0 -1.58 -2. 06

-Ho 9,14 8.16 7.73 7.34 6.98 6.57 6, 22 6.14 5.85

•»Go 18,94 16.52 15,61 14. 88 14,19 13,38 12,68 12,54 11,95 162 Table 29 o “Toluic Acid

Temp. 10° Conc. O.OIM Dilution l/lOO ^max, 7,300 A 231. 5mu kg = 0.454

t (min. ) A l/c

0 0.730 100 6 0. 701 104 59 0. 568 129 94 0.507 144 100 0.481 152 168 0. 410 178 235 0. 351 208 295 0.316 231 351 0.280 261 479 0.228 320 570 0. 205 356 705 0.173 422 760 0.162 451

Table 30 o-Tolnic Acid

Temp, 10° Conc, O.OIM Dilution 1 /l 00 ^max, A 2 3 1 .5mu kz = 0.460

t (min. ) A l/c

0 0.730 100 6 0.706 103 59 0.571 128 94 0.511 143 110 0,475 154 168 0.410 178 235 0.349 209 295 0.309 236 351 0.278 263 479 0.229 319 570 0.203 360 705 0.171 427 760 0.162 451 163 T able 31 o-Toluic Acid

Temp, 10® Conc, 0, OIM Dilution lA 00 Exnax. 7.300 A 231,5mu 3C2 = 0,462

t(m in.) A 1/c

0 0.730 100 6 0.718 102 59 0. 572 128 94 0.512 143 110 0,484 151 168 0.415 176 235 0. 354 206 295 0.309 236 350 0.280 26l 479 0.230 317 570 0.204 358 705 0.172 424 760 0.162 451

Table 32 o-Toluic Acid

Temp, 20® Conc, 0, OIM Dilution l/l 00 Emax, 7,300 A 2 3 1 ,5mu k2 = 1,565

t{min. ) A 1/c

0 0.730 100 8 0. 640 114 31 0. 493 148 47 0.417 175 65 0. 360 203 88 0. 314 232 110 0.273 267 154 0.217 336 191 0.182 401 230 0.156 468 274 0.141 518 313 0.123 593 476 0. 090 811 164 T able 33 o-Toluic Acid

Temp, 20° Conc. O.OIM Dilution 1/100 Emax. 7,300 X 231,5mu kg = 1.56

t(inin, ) A l/c

0 0,730 100 8 0, 642 114 31 0.505 145 47 0,419 174 65 0, 374 195 88 0,313 233 110 0, 277 267 154 0,218 335 191 0,183 399 230 0,158 462 274 0,141 518 313 0,123 593 476 0,090 811

Table 34 o-Toluic Acid

Temp, 20° Conc. 0, OIM Dilution 1/100 Emax, 7*300 X 231,5mu kg = 1,56

t(m in, ) A i/c

0 0,730 100 8 0, 650 112 31 0, 519 141 47 0,426 171 65 0,369 198 88 0, 317 230 110 0,274 266 154 0, 220 332 191 0,185 395 230 0,159 459 274 0,140 521 313 0.124 589 476 0. 089 820 165 T able 35 o-T oluic Acid

Temp, 0® Conc. 0.00375M Dilution 2/50 ®max, ^ 231, 5mu kg = 0.126

t(m ia,) A l/c

0 1.100 267 2 1.103 265 63 0. 998 292 132 0.963 303 180 0. 950 307 213 0. 920 317 342 0. 885 329 446 0. 870 335 825 0.737 396 1213 0.687 425 1514 0. 626 467 1728 0.598 487 2109 0,537 543 2660 0.475 614 3182 0.425 686 3656 0.394 740 4120 0.364 804 4627 0. 340 858 5130 0.316 924 5735 0.289 1012 6583 0.262 1117 7475 0.238 1227 166 Table 36 o-Toluic Acid

Temp. 0* Conc. 0.00375M Dilution Z/50 Emax, 7,300 \ 231,5mu kg = 0.126

t(mm, ) A l/c

0 1.100 267 3 1.030 281 65 0. 980 298 134 0. 965 302 182 0.955 306 215 0. 925 315 344 0.892 327 450 0. 845 345 827 0. 755 386 1216 0. 674 432 1516 0. 612 477 1731 0.590 494 2111 0.524 555 2663 0.470 621 3184 0.432 675 3658 0. 393 742 4122 0.364 803 4629 0, 336 869 5134 0. 313 932 5736 0.293 995 6585 0.257 1138 7478 0.233 1253 167 T able 37 o^-Ethylbenzoic Acid

Temp. 10* Conc. O.OIM Dilution l / l 00 ^naax, ^00 ^ 232mu kz = 1,035

t(m in, ) A 1/c

0 0. 680 100 5 0.577 118 41 0.429 159 88 0.329 207 120 0.281 242 ISO 0.223 305 240 0.187 364 290 0.163 417 346 0.145 470 493 0,113 602 660 0. 089 764

Table 38 o -Ethylb enzoic Acid

T emp, 10* Conc, O.OIM Dilution l/l 00 Emax. 6,800 232mu kz — 1. 045

t(m in, ) A 1/c

0 0. 680 100 5 0,576 118 41 0.426 160 88 0.325 209 120 0.280 243 180 0. 223 305 240 0,184 370 290 0.161 422 346 0.143 476 493 0,113 602 660 0.088 773 168 T able 39 o_-Ethylbenzoic Acid

Temp. 10° Conc, O.OIM Dilution l/lOO ^max, ^ 232mu kz = 1.04

t(m in.) A l/c

0 0.680 100 5 0.562 119 41 0.427 160 88 0. 325 209 120 0.279 244 180 0. 223 305 240 0.185 368 290 0.162 420 346 0.143 476 493 0.112 607 660 0.090 755

Table 40 o-Ethylbenzoic Acid

Temp. 20° Conc. O.OIM Dilution l/l 00 ^m ax. 800 \ 232mu kz =2123

t(min, ) A l/c

0 0,680 100 5 0.539 126 17 0.419 162 29 0.332 205 45 0.261 261 60 0.224 303 79 0.186 366 96 0.163 418 130 0,128 531 166 0.107 636 205 0,094 723 169 Table 41 o-Ethylbenzoic Acid

Temp, 20° Conc, O.OIM Dilution l/l 00 Emax, 6,800 232mu kz = 3,30

t(min, ) A . l/c

0 0,680 100 5 0.516 132 17 0,406 167 29 0,327 208 45 0,259 263 60 0,219 310 79 0.181 376 96 0.159 428 130 0.126 540 166 0,106 642 205 0.091 747

Table 42 o-Ethylbenzoic Acid

Temp, 20° Conc, O.OIM Dilution l/l 00 Emax, 6,800 \ 232mu kz = 3,18

t(min, ) A l/c

0 0.680 100 5 0.499 136 17 0.396 172 29 0. 324 210 45 0.257 265 60 0.220 309 79 0.183 372 97 0.160 426 130 0.129 527 l66 0.113 602 205 0.096 708 170 T able 43 o-Ethylbeazoic Acid

Temp, 30° Conc. O.OIM Dilution l/l 00 ^max, \ 232mu kg = 8.64

t(min. ) A l/c

0 0. 680 100 2.7 0.513 133 5.2 0. 436 157 8.9 0.362 188 14.2 0.283 240 20.5 0.232 293 25.9 0.205 332 32.3 0.177 384 38.0 0.162 420 46.5 0.139 489 54.6 0.127 535

Table 44 o-Etbyibenzoic Acid

Temp. 30° Conc. O.OIM Dilution l/ï 00 ^max. ^00 \ 232mu k% = 8.80

t(min. ) A l/c

0 0. 680 100 2.7 0.485 140 5.2 0.424 160 8.8 0.356 191 14.0 0.284 239 20.3 0. 228 298 25.9 0.198 343 32.1 0.174 391 38.3 0.158 430 46.3 0.137 496 5 4.4 0.125 544 171 T able 45 o^-Ethylbenzoic Acid

Temp. 30® Conc. O.OIM. Dilution l/lOO Emax. 6,800 \ 232mu kg = 8.96

A t(miii, ) _ _ 1/c

0 0,680 100 2.8 0.487 139 5,6 0.412 163 9.0 0.343 197 14.0 0.283 240 20.1 0.232 293 26.0 0.203 335 31.8 0.177 384 38.4 0.155 438 46.2 0.143 476 54.4 0.132 516

Table 46 o-Isopropylbenzoic Acid

Temp. 0® Conc. O.OIM. Dilution l/50 Ejnax. 950 228mu kg = 0.93

t(min. ) A 1/c

0 0. 990 100 5 0. 854 116 17 0.765 129 49 0.604 164 84 0.504 196 118 0.440 225 151 0. 378 262 183 0.342 289 222 0. 305 325 277 0.264 375 342 0.231 429 172 T able 47 o-Isopropylbenzoic Acid

Temp, 0* Conc. O.OIM. Dilution ^m ax, 950 y\ 228mu kz = 0.97

t(m in.) A 1/c

0 0.990 100 6 0. 854 116 17 0.766 129 49 0. 614 161 84 0.506 196 118 0.437 227 151 0.379 261 184 0.345 287 222 0.305 325 277 0. 263 376 342 0.232 427

Table 48 o-Isopropylbenzoic Acid

Temp, 0® Conc. 0. OIM, Dilution l/50 4.950 228mu kz = 0.98

t(min, ) A 1/c

0 0.990 100 7 0. 874 113 17 0.782 127 49 0. 643 154 84 0.505 196 118 0.437 227 151 0.376 263 184 0.350 283 222 0. 302 328 277 0.260 381 342 0.233 425 173 Tablé 49 o-Isopropylbenzoic Acid

Temp. 10® Conc. O.OIM Dilution l/50 ^max, 950 228mu kz = 3.10

t(min. ) A l/c

0 0.990 100 4 0.819 121 8.5 0.727 136 22.5 0.546 181 36 0.440 225 50 0.365 271 69 0.309 320 92 0. 251 394 112 0.213 465 137 0.185 535 164 0,161 615 196 0.139 712

Table 50 o-Isopropylb enzoic Acid

Temp. 10° Conc. O.OIM Dilution 1/50 Emax, 4,950 228mu kz = 3.09

t(xnin. ) A 1/c

0 0.990 100 5 0.802 123 9 0.718 138 22 0.543 182 36 0.431 230 50 0.374 265 69 0.312 317 92 0. 253 391 112 0.219 452 137 0.188 527 164 0.163 607 196 0.142 697 174 T able 51 o^-Isopropylbenzoic Acid

Temp. 10® Conc. O.OIM Dilution l/50 ^m ax, 950 ^ 228mu kg = 3.07

t(irdn, ) 0 A l/c

0 0.990 100 5 0.804 123 10 0.712 139 22 0.551 180 36 0.434 228 50 0.372 266 70 0.306 324 92 0.252 393 112 0. 214 463 137 0.188 527 164 0.162 611 196 0.141 702

Table 52 o-Isopropylbenzoic Acid

Temp, 20° Conc. O.OIM Dilution l/5Q Emax. 4.950 X 228mu kg = 8.68

t{min, ) A l/c

0 0.990 100 2 .9 0.716 138 6.5 0.584 170 11.3 0.460 215 16.3 0.387 256 22.0 0.322 307 29.3 0.269 368 37.6 0.228 434 44.9 0. 204 485 53.9 0.188 527 64.7 0.157 631 175 Table 53 o-Isopropylbenzoic Acid

Temp, 20° Conc. O.OIM Dilution l/50 ^méix, 950 \ 228mu kg = 8.76

t(min. ) A l/c 1 1 1 1 1

0 0. 990 100 3.2 0. 699 142 6.6 0,575 172 11.1 0,468 212 l6. 6 0, 383 258 21.8 0.326 304 29.0 0,274 361 27,3 0,232 427 44.6 0. 206 481 53.6 0,182 544 64.3 0.160 619

Table 54 o-Isopropylbenzoic Acid

Temp. 20° Conc. O.OIM Dilution l/50 Emajc 4,950 X 228mu kz = 8.48

t(min. ) A l/c

G 0.990 100 3.0 0. 703 141 6.5 0.577 172 11.3 0.466 212 16.5 0,381 260 21.6 0.330 300 28.7 0.276 359 37,4 0. 232 427 44,6 0.210 471 53,3 0.187 529 64,0 0.164 604 176 Table 55 o-tert-Butylbenzoic Acid

T emp, 0° Conc. 0.0025M Dilution 5/50 Eo 7,480 Eco 2,120 \ 219mu kg = 6.72

A q t(min, ) A » A ) . l/c

G 0. 935 0.670 400 7 0.877 0.612 438 17 0.780 0.515 520 30.5 0.698 0.433 619 46.5 0. 645 0.380 705 66 0.582 0.317 845 85 0.544 0.279 961 107 0.512 0.247 1085 140 0.474 0.209 1283 00 0.265

Table 56 o-tert-Butylbenzoic Acid

Temp, 0° Conc. Û.0025M Dilution 5/50 Eo 7,480 Em 2,120 X 219nau kg = 6. 87

t(min. ) A A - A® l/c __

0 0, 935 0.670 400 7 0.850 0.585 458 17 0.781 0.516 519 31 0. 691 0.426 629 47 0.638 0.373 718 66 0.573 0.308 870 85 0.530 0.265 1011 107 0.504 0.239 1121 140 0.458 0.193 1389 00 0.265 177 Table 57 o-te rt-Butylb enzoic Acid

Temp, 0* Conc, 0.0025M Dilution 5/50 Eo 7,480 Eflo 2,120 \ 219mu kg = 6,70

t(min. ) A A - A® l/c

0 0.935 0.670 400 7 0, 856 0.591 453 17 0.792 0.527 509 31 0.708 0.443 605 51 0. 626 0.361 742 72.5 0. 562 0.297 902 90 0.526 0.261 1027 114.5 0.496 0.231 1160 140 0. 457 0.192 1396 OD 0.265

Table 58 o-tert»*Butylbenzoic Acid

Temp, 10° Conc, 0.0025M Dilution 5/50 Eo 7,480 E® 2,120 \ 2l9mu kg — 21,7

t(min, ) A A - A® l/c

0 0,935 0.670 400 4 0.780 0,515 520 11 0, 634 0.369 726 29 0,518 0,253 1059 41 0,467 0,202 1327 55 0.429 0,164 1634 70 0,404 0,139 1928 85 0,382 0,117 2291 101 0,368 0.103 2602 m 0,265 178 T able 59 o-te rt-Butylb enzoic Acid

Temp. 10° Conc, 0.0025M Dilution 5/5 0 Eo 7,480 E(o 2,120 X 219mu kg = 21, 35

t(min, ) A A - A(d l/c

0 0.935 0.670 400 4.5 0. 779 0.514 521 16 0. 619 0.354 757 30 0.512 0.247 1085 42 0.460 0.195 1374 56.5 0.433 0,168 1595 70 0.409 0.144 1861 86 0. 388 0.123 2179 101 0.368 0.103 2602 CD 0.265

Table 60 _o-tert-Butylbenzoic Acid

T emp. 10* Conc, 0.0025M Dilution 5/50 Eo 7,480 E(d 2,120 X 219mu kg = 22.4

t(min. ) A A - A(j) l/c

0 0. 935 0,670 400 5 0.742 0.477 562 16.5 0.599 0,334 802 30 0.510 0.245 1082 43 0,455 0,190 1411 57 0. 424 0.159 1686 71 0.397 0,132 2030 87 0.376 0.111 2414 101 0.366 0.101 2653 œ 0.265 179 T able 6l o-tert-Butylbenzoic Acid

Temp, 20° Conc. 0.0025M Dilution 5/5 0 Eo 7,480 Em 2,120 \ 219mu kz = 59.2

t(mia, ) A A - Ajo 1/c

0 0.935 0.670 400 3.6 0.691 0.426 629 7.8 0.574 0.309 867 12.6 0.496 0.231 1160 17.9 0.455 0.190 1410 23.3 0.413 0.148 1811 29.8 0.388 0.123 2179 39.5 0. 364 0.099 2707 48.9 0.347 0.082 3268 CO 0.265

Table 62 0-tert-Butylbenzoic Acid

Temp. 20° Conc. 0.0025M Dilution 5/SO Eo 7.480 Ea 2.120 \ 219mu k z = 59. 6

t(min. ) A A - Am 1/c

0 0.935 0.670 400 3.9 0.685 0.420 638 8.4 0.562 0.297 902 13.1 0.490 0.225 1191 18.3 0,440 0.175 1531 24.0 0.409 0.144 1861 30.4 0.388 0.123 2179 39.8 0.365 0,100 2680 49.3 0.344 0.079 3390 00 0.265 180 T ab le 63 o-tert-Btttylb enzoic Acid

Temp, 2C® Conc. 0.0025m Dilution 5/50 Eo 7,480 Em 2,120 X 219mu kz = 6l.4

t(min. ) A A “ A® 1/c

0 0.935 0.670 400 4 .3 0.682 0.417 643 8.9 0. 549 0.284 944 13.3 0.478 0.213 1258 18.6 0.437 0.169 1586 24,7 0.404 0.139 1928 30.8 0.389 0,124 2161 40.6 0.361 0,096 2792 49.7 0. 347 0.082 3268 00 0.265

Table 64 o-Fluorobenzoic Acid

Temp. 20® Conc. 0.05 Dilution 1/500 Emax. i 0*000 ^ 227mu kz = 0. 00539

t(min. ) A 1/c

0 1.000 20.0 8 0.996 20.1 122 0.963 20.8 271 0. 930 21,5 454 0. 895 22.4 601 0. 852 23.5 770 0. 827 24.2 1200 0.759 26.4 1408 0.725 27.6 1778 0.674 29.7 2127 0.633 31.6 2640 0. 593 33.7 181 T ab le 65 o-Fluorobenzoic Acid

Temp, 200 Conc, 0,05M Dilution 1/500 ^max. 10,000 A 227mu kg — 0. 00528

t(min, ) A 1/c

0 1.000 20.0 8 0.996 20.1 122 0.964 20.8 271 0.930 21.5 454 0.891 22,5 601 0.856 23.4 770 0. 827 24.2 1200 0. 759 26.4 1408 0.727 27.5 1778 0. 675 2 9 .6 2127 0.643 31.1 2640 0.599 33.4

Table 66 o-Fluorobenzoic Acid

Temp. 20° Conc. 0 ,05M Dilution 1/500 ^max. 10,000 \ 227mu kg — 0. 00530

t(min, ) A 1/c

0 1.000 20.0 6 1.002 20.0 120 0.971 20.6 269 0.927 21.6 452 0.894 22.4 600 0.864 23.2 768 0.827 24.2 1198 0.765 26.1 1406 0. 730 27.4 1776 0. 682 29.3 2125 0. 640 31.3 2638 0.594 33,7 182 T able 67 o-Fluorobenzoic Acid

Temp, 30° Conc. 0.0 5M Dilution 1/500 ^max. 10, 000 A 227mu kg = 0. 0204

t(min, ) A l/c

0 1.000 20.0 6 0.976 20.5 46 0.946 21.1 117 0.893 22.4 200 0. 825 24.2 275 0.770 25.3 343 0. 736 27.2 444 0, 683 29.3 561 0.634 31.6 646 0. 599 33.4 743 0. 568 35.2

Table 68 o-Fluor»benzoic Acid

Temp. 30* Conc. 0 .05M Dilution 1/500 Emax. 10, 000 A 227mu kz = 0. 0203

t(min. ) A l/c

0 1. 000 20.0 6 0. 990 20.2 46 0. 954 21.0 117 0. 889 22.5 202 0. 828 24.2 275 0,784 25.5 342 0, 745 26.9 444 0. 685 29.2 561 0.636 31,5 646 0.604 33.1 743 0.579 34.5 183 Table 69 o-Fluorobenzoic Acid

Temp. 30® Conc. 0 .05M Dilution 1/500 Emax. 10,000 227mu kg = 0. 0200

t(miu. ) A l/c _

0 1.000 20.0 5 0.982 20.4 44 0.950 21.1 116 0.897 22.3 201 0.826 24.2 274 0.774 25.8 341 0.738 27.1 443 0.688 29.1 560 0. 634 31.5 645 0.605 33.1 742 0. 576 34.7

Table 70 o-Fluorobenzoic Acid

Temp, 40° Conc. 0 ,05M Dilution 1/500 ^max. 10,000 227mu kg — 0, 0700

t(min, ) A l/c

0 1.000 20.0 7 0.968 20.7 22 0.932 21.5 45 0.864 23.2 80 0.779 25.7 111 0.718 27.9 140 0. 674 29.7 166 0.631 31.7 189 0. 604 33.1 220 0. 564 35.5 270 0. 522 38.3 184 T able 71 o—Fluorob enzoic Acid

Temp, 40° Conc, 0 ,05M Dilution 1/500 ^max. 10,000 \ 227mu kg = 0. 0697

t(min. ) A l/c

0 1,000 20.0 7 0.972 20.6 22 0.932 21.5 45 0.864 23.2 80 0,778 25.7 111 0.717 27.9 140 0,656 30,5 166 0.634 31.6 189 0.602 33.2 220 0,564 35,5 270 0, 525 38.1

Table 72 o-Fluorobenzoic Acid

Temp, 40° Gone, 0 ,05M Dilution l/SOO ^max. 10, 000 X 227mu kg = 0, 0685

t(miu, ) A l/c

0 1.000 20,0 7 0.969 20.6 22 0.932 21,5 45 0.863 23,2 80 0,773 25.9 111 0,717 27,9 140 0. 675 29,6 166 0, 631 31.7 189 0,602 33.2 220 0.569 35.2 270 0.530 37,7 185 Table 73 o-Chlorobenz#ic Acid

Temp, 10° Conc. O.OIM Dilution l/50 Eo 5,230 E@ 450 X, 230mu kg = 0.050

t(min. ) A A - A® l/c

0 1.135 1.045 100 13 1.120 1.030 101.5 52 1.097 1.007 103.8 117 1.072 0.982 106.4 181 1.064 0.974 107.3 268 1.015 0.925 113.0 382 0,972 0.882 118.5 549 0.918 0,828 126.2 642 0.884 0.794 131.6 788 0.857 0.767 136.3 1244 0.735 0.645 162.0 1520 0.681 0.591 178.8 o 0.090

Table 74 o-CMorobenzoic Acid

Temp. 10° Conc. O.OIM Dilution l/50 Eo 5,230 Eo, 450 X 230mu kg = 0. 049:

t(min, ) A A - A® l/c

0 1.135 1.045 100 12 1.127 1.037 100.8 51 1.106 1.016 102.9 116 1.078 0.988 105.8 180 1.062 0.972 107.5 267 1.020 0.930 112.4 381 0.971 0.881 118.6 548 0.916 0.826 126.5 641 0,883 0.793 131.8 787 0,846 0.756 138.2 1243 0.731 0, 641 163.0 1519 0.689 0.599 174.5 00 0.090 186 Table 75 o-Chlorobenzoic Acid

Temp, 10® Conc, O.OIM Dilution l/50 Eo 5,230 Eflo 450 230mu = 0. 0493

t(min. ) A A — A(d l/c

0 1.135 1.045 100 9 1,133 1.043 100,2 48 1.110 1.020 102,5 113 1.082 0.992 105,3 177 1.062 0.972 107.5 264 1.019 0.929 112,5 378 0. 978 0.888 117.7 545 0. 914 0.824 126.8 638 0.890 0.800 130.6 784 0. 845 0.755 138.4 1240 0. 742 0. 652 160.3 1516 0. 688 0,598 174.7 m 0. 090

Table 76 o-Cblorobenzoic Acid

Temp, 20* Conc. O.OIM Dilution l/50 Eo 5,230 Eod 450 A 230mu kz = 0,190

)A A — A(q l/c

0 1,135 1,045 100 6 1,118 1,028 101.7 34 1,074 0.984 106.2 71 1.012 0.922 113.4 103 0,965 0.875 119.5 147 0.910 0.820 127.5 215 0.831 0, 741 141.1 299 0, 768 0, 678 154,2 380 0.695 0, 605 172,8 518 0.615 0.525 199,1 607 0.569 0.479 218,2 745 0.509 0.419 249.4 00 0.090 187 T able 77 o-Chlorobenz»ic Acid

Temp, 20® Conc, O.OIM Dilution l/50 Eo 5,230 E

t(min. ) A A - Affl l/c

0 1.135 1.045 100 6 1,113 1.023 102.2 35 1.096 1.006 103.9 71 1.007 0.917 114.0 103 0, 967 0.877 119.2 147 0.913 0.823 127.0 215 0.832 0.742 140.8 299 0. 759 0.669 156.2 380 0.695 0.605 172.7 518 0.615 0.525 199.0 607 0.570 0.480 217.7 745 0. 514 0.424 246.5 m 0.090

Table 78 o-Chlorobenzoic Acid

Temp, 20° Conc. O.OIM Dilution l/50 Eo 5,230 Ego 450 \ 230mu kz = 0.192

t(min, ) A A - A(o l/c

0 1.135 1.045 100 6 1.121 1.031 101.4 35 1.078 0.988 105.8 71 1.017 0.927 112.7 103 0. 967 0.877 119.2 147 0.912 0.822 127.1 215 0.831 0.741 141.0 299 0.760 0.670 156.0 380 0.695 0.605 172.7 518 0. 614 0.524 199.4 607 0.570 0.480 217.7 745 0.510 0.420 248.8 m 0.090 188 Table 79 o-Chlorobenzoic Acid

Temp. 30® Conc, O.OIM Dilution 1/50 Eo 5,230 Efl) 450 \ 230mu k2 = 0. 662

t(min. ) A A - A® l/c

0 1.135 1.045 100 6 1.094 1.004 104.1 15 1.054 0.964 108.4 37 0. 942 0.852 122.7 61 0.844 0.754 138.6 88 0.755 0.665 157.2 110 0.703 0.613 170.5 141 0. 634 0,544 192.1 167 0.590 0.500 209.0 219 0.519 0.429 234.6 363 0. 388 0.298 350.7 o> 0. 090

Table 80 o-Chlorobenzoic Acid

Temp. 30® Conc, O.OIM Dilution l/50 Eo 5,230 E® 450 ^ 230mu kg = 0.655

t(min. ) A A - A® l/c

0 1.135 1.045 100 6 1,092 1.002 104.3 15 1.053 0.963 108.5 37 0. 944 0.854 122.4 61 0.845 0.755 138.4 88 0.762 0.672 155.5 110 0.699 0.609 171.6 141 0.634 0.544 192.1 167 0.592 0.502 208,2 219 0.528 0.438 238.6 363 0.393 0.303 344.9 œ 0. 090 189 Table 81 o-C hlorobenzoic A cid

Temp, 30° Conc, O.OIM Dilution l/5 0 Eo 5,680 E

t(min, ) A A - A® l/c

0 1,135 1,045 100 5 1,095 1.005 104.0 14 1,054 0.964 108.4 36 0,942 0.852 122.7 60 0. 843 0.753 138.8 87 0,766 0.676 154. 6 109 0.720 0.630 165.9 140 0,652 0.560 186. 6 166 0,589 0.499 209.4 218 0,530 0.440 237.5 362 0, 386 0.296 353,0

OD 0,090 190 T able 82 o-Chlorobenzoic Acid.

Temp, 25° Conc. 0.00333M Dilution 5/l 00 Eo 5,680 Eœ 390 \ 230mu , kg = 0. 360

t(min, ) A A — Aq) l/c

0 0. 948 0.883 300 3 0. 941 0. 876 303 20 0.915 0.850 312 60 0.881 0.816 325 98 0. 851 0.786 338 135 0.811 0.746 356 161 0.796 0.731 363 200 0. 768 0.703 377 265 0.733 0.668 297 338 0. 698 0.633 418 425 0.656 0.591 448 536 0. 601 0.536 495 756 0.533 0.468 566 1192 0.425 0.360 736 1692 0.361 0.296 895 2110 0.318 0.253 1049 4200 0.236 0.171 1550 00 0.065 191 Table 83 o-Chlorobenzoic Acid

Temp. 25® Conc, 0.00333M Dilution 5/l 00 Eo 5,680 E(o 390 \ 230mu kg = 0. 362

t(min. ) A A - Aq) l/c

0 0.948 0.883 300 1 0. 948 0.883 300 3 0.941 0.876 303 7 0.934 0.869 305 12.5 0.915 0.850 312 23 0.903 0.838 316.5 36 0.892 0.827 321 63 0.876 0.811 327 91 0.852 0.787 337 147 0.798 0.733 362 195 0.770 0.705 376 229 0.766 0.701 379 326 0.698 0.633 418 405 0.665 0.600 442 502 0.611 0.546 486 809 0.516 0.451 588 1260 0.414 0.349 760 1697 0.355 0.290 915 2177 0.312 0.247 1073 2763 0.274 0.209 1268

QO 0.065 192 T able 84 o-Chlorobenzoic Acid

Temp, 25° Conc, 0.00333M Dilution 5/l 00 Eo 5,680 Eg, 390 ^ 230mu kg = 0. 363

t(min, ) A A — Afl) l/c

0 0.948 0.883 300 2 0.934 0.869 305 19 0.909 0. 844 315 59 0. 881 0,816 325 97 0. 842 0.777 346 134 0. 809 0.744 356 160 0.795 0.730 363 199 0.762 0.697 380 264 0.738 0.673 393 337 0.697 0.632 420 428 0.649 0.584 454 535 0.601 0.536 495 755 0.525 0.460 576 1191 0.426 0.361 735 1629 0.362 0.297 892 2110 0.319 0.254 1043 4200 0. 237 0.172 1540 a> 0.065 193 Table 85 o-Bromobenzoic Acid

Temp. 10° Conc, O.OIM Dilution l/lOO Eo 5, 600 E(d 1.100 ^ 232mu kg = 0,108

t(min. ) A A — A(p 1/c

0 0.560 0.450 100 7 0.550 0.440 102 55 0.537 0.427 105 210 0. 474 0.364 124 305 0.450 0.340 132 423 0.415 0.305 148 531 0. 395 0.285 158 687 0.368 0.258 174 780 0.351 0.241 187 GD 0.110

Table 86 o-Bromobenzoic Acid

Temp, 10° Conc, O.OIM Dilution l/lOO Eo 5,600 E(d \ 232mu kg = 0.103

t(min, ) A A - Afl) 1/c

0 0.560 0.450 100 7 0.552 0.442 102 55 0.531 0.421 107 210 0.480 0.370 122 305 0.448 0.338 133 423 0.423 0.313 144 532 0.400 0.290 155 687 0. 370 0.260 173 780 0.358 0.248 182 CD 0.110 194 Table 87 o-Bromobenzoic Acid

Temp, 10® Conc, 0, OIM Dilution l/lOO Eo 5,600 E(d 1.100 \ 232mu kg= 0,103

t(min. )______A______A - Ap______l/(

0 0.560 0.450 100 7 0.553 0.443 102 55 0.534 0,424 106 210 0.482 0.372 121 305 0.453 0.343 131 423 0.425 0,315 143 532 0.404 0,294 153 687 0.373 0.263 171 780 0.357 0,247 182 m 0.110

Table 88 o-Bromobenzoic Acid

Temp, 20° Conc, O.OIM Dilution 1 /l 00 Eo 5,600 Ea 1,100 \ 232mu kz = 0,381

t(min, ) A A - A® 1/c

0 0.560 0.450 100 5 0.548 0,438 103 28 0.520 0,410 110 85 0.450 0,340 132 141 0.405 0.295 153 209 0.360 0.250 180 286 0. 328 0.218 206 377 0,294 0.184 245 479 0.274 0.164 274 577 0.251 0.141 319 685 0,233 0,123 366 758 0.229 0.119 378 CD 0.110 195 Table 89 o-Bromobenzoic Acid

Temp. 20° Cone. 0. OIM Dilution l/lOO Eo 5,600 E(o 1,100 ^ 232mu kz = 0. 372

t(min. ) A A “ A® 1/c

0 0. 560 0.450 100 5 0.553 0.443 102 28 0.520 0.410 110 85 0.448 0.338 133 141 0.402 0.295 153 209 0.362 0.252 179 286 0. 328 0.218 206 377 0.297 0.187 241 479 0.274 0.164 274 577 0. 254 0.144 313 685 0.234 0.128 363 758 0.228 0.118 381 0 9 0.110

Table 90 o-Bxomobenzoic Acid

Temp. 200 Cone. O.OIM Dilution l/lOO Eo 5,600 Efl, 1,100 \ 232mu k z = 0. 380

t(min, ) A A ~ A® 1/e

0 0.560 0.450 100 5 0.553 0.443 102 28 0. 520 0.410 110 85 0.448 0.338 133 141 0.402 0.295 153 209 0.362 0.252 179 286 0. 328 0.218 206 377 0.297 0.187 241 479 0.274 0.164 274 577 0. 254 0.144 313 685 0. 234 0.124 363 758 0. 228 0.118 381

OD 0.110 196 T a b le 91 o-Bromobenzoic Acid

Temp. 30® Cone, O.OIM Dilution l/lOO Eo 5,600 Eg) 1,100 ^ 232mu k2 = 1.295

t(mia, ) A A — Aq) 1/c

0 0.560 0.450 100 10 0.528 0.418 108 23 0.458 0.348 129 40 0.405 0.295 153 64 0. 356 0. 246 183 84 0.328 0.216 208 106 0.301 0.191 236 134 0.275 0.165 273 158 0.255 0.145 310 189 0.236 0.126 357 218 0.221 0.111 405 248 0.211 0.101 446 m 0.110

Table 92 o-Bromobenzoic Acid

Temp. 30« Cone, O.OIM Dilution l/lOO Eo 5,600 Eg) 1,100 \ 232mu kz = 1,345

t(min. ) A A — Ag) 1/c

0 0.560 0.450 100 10 0.526 0.416 108 23 0.456 0.346 130 40 0.413 0.303 149 64 0.358 0.248 182 84 0.324 0.214 210 106 0.297 0.187 241 134 0,272 0.162 279 158 0.256 0.146 308 189 0.239 0.129 349 218 0.226 0.116 388 248 0.221 0.111 405 GO 0.110 197 T able 93 o-Bromobenzoic Acid

Temp. 30® Conc. O.OIM Dilution 1/100 Eo 5,600 Eflo 1,100 X 232mu kg = 1.25

t(min, ) A A - A{d l/c

0 0.560 0.450 100 10 0. 532 0.422 107 22 0. 458 0.348 129 39 0. 408 0.298 151 63 0. 357 0.246 183 83 0. 328 0.218 206 105 0, 303 0.193 233 133 0. 274 0.164 274 157 0.258 0.148 304 187 0.242 0.132 341 217 0.233 0.123 366 246 0. 221 0.111 405 oo 0.100

Table 94 o-Bromobenzoic Acid

Temp, 25° Conc, 0.00333M Dilution 5/100 Eo 5,460 Ego 1 ,1 1 0 \ 232mu kg = 0.694

t(min. ) A A “ Ag) l/c

0 0.910 0. 725 300 8 0. 900 0.715 304 32 0.863 0.678 319 75 0. 805 0.620 351 172 0.696 0.511 426 267 0.631 0.446 488 347 0.587 0.412 527 530 0.509 0.324 671 730 0.445 0.260 835 1330 0. 365 0.180 1207 2840 0. 301 0.116 1875 m 0. 185 198 Table 95 o-Bromobenzoic Acid

Temp, 25° Conc, 0 ,00333M Dilution 5/100 Ep 5,460 Eco 1,110 A 232mu kg = 0,704

t(mia, ) A A - A(j) l/c

0 0. 910 0.726 300 8 0. 906 0,721 302 32 0.966 0.681 319 75 0. 807 0,622 350 172 0,711 0.526 413 267 0. 637 0,452 482 351 0.578 0.393 553 530 0.504 0,319 682 730 0.461 0,276 787 1330 0. 360 0,175 1242 2840 0. 304 0,119 1830 00 0.185

Table 96 o-Bromobenzoic Acid

Temp, 25® Conc. 0.00333M Dilution 5/100 Eo 5,460 Eco 1,110 A 232mu kg = 0. 702

t(min, ) A A - Ago l/c

0 0.910 0. 725 300 6 0.909 0.724 300 32 0,866 0.681 319 75 0.804 0.619 351 172 0.704 0.519 418 267 0.625 0.450 483 347 0.586 0,401 ■ 543 530 0. 503 0.318 684 730 0.455 0.270 806 1330 0.359 0.174 1250 2840 0.310 0.125 1740 03 0.185 199 Table 97 o-Iodobenzoic Acid

Temp, 10° Conc, 0, OlM Dilution l/5 0 Eo 5,950 E jd 2,050 \ 24lmu kg = 0.460

t(min. ) A A - Aflj l/c

0 1,190 0,780 100 6 1.181 0,771 101 40 1,080 0,670 116 97 0,970 0,560 139 189 0,827 0.417 187 287 0,758 0,348 224 424 0,681 0,271 288 580 0.625 0,215 363 712 0.602 0,192 406 940 0.558 0,148 527 1340 0,522 0,112 696 1652 0.495 0,085 918

GO 0.410

Table 98 o-Iodobenzoic Acid

Temp, 10“ Conc, O.OIM Dilution l/50 Eo 5,950 E (D 2,050 \ 241 mn kg = 0.434

t(miiL, ) A A - Ag) l/c

0 1,190 0.780 100 6 1,174 0.764 102 40 1,065 0,655 119 97 0,962 0,552 141 189 0,834 0.424 161 287 0,771 0.361 216 424 0,685 0,275 284 580 0,637 0,227 344 712 0,601 0,191 408 940 0.562 0,152 513 1340 0,524 0,114 684 1652 0,500 0,090 867 00 0,410 200 Table 99 o-Iodobenzoic Acid

Temp, 10° Conc. 0, OlM Dilution l/5 0 Eo 5,950 Eflo 2,050 X 24lmu kz = 0.450

t(min. ) A A - A(o l/c

0 1.190 0,780 100 6 0,085 0.769 101 40 0,974 0.675 116 97 0.837 0.564 138 189 0.763 0.427 183 287 0.684 0.353 221 423 0.626 0.274 285 580 0,597 0.216 361 712 0.560 0.187 417 940 0,521 0.150 520 1340 0.495 0.111 703 1652 0,488 0,085 918 m 0.410

Table 100 o-Iodobenzoic Acid

Temp. 20° Conc. O.OIM Dilution l/50 Eo 5,950 E(b 2,050 \ 241mu kz = r .sm

t(min. ) A A - AgQ l/c

0 1.190 0.780 100 5 1. 119 0.709 110 28 0.952 0. 542 144 63 0.816 0.406 192 116 0.690 0.280 270 I6l 0.643 0.233 335 215 0.592 0.182 429 294 0.555 0.145 538 390 0.519 0.109 716 540 0.495 0.085 918 687 0.477 0.067 1164 913 0.470 0.060 1300 m 0.410 201 Table 101 o-Iodobenzoic Acid

Temp, 20® Conc, 0, OlM Dilution l/50 Eo 5,950 E (d 2,050 ^ 241 mu. k z = 1.51

t(min. ) A A - Aflo l/c

0 1.190 0.780 100 5 1.121 0.711 110 28 0.952 0.542 145 63 0.819 0.409 191 116 0.691 0.281 277 161 0.640 0.230 339 215 0.593 0.183 426 294 0.555 0.145 538 390 0.520 0.110 710 540 0.495 0.085 9 1 8 687 0.480 0.070 1114 913 0,464 0.054 1444 CD 0.410

Table 102 o-Iodobenzoic Acid

Temp. 20° Conc. 0. OlM Dilution l/50 Eo 5,950 Eqj 2,050 \ 241 mu k z = 1.54

t(min, ) A A — Ag) l/c

0 1.190 0.780 100 4 1.129 0.719 109 27 0.952 0.542 144 62 0.811 0.401 196 115 0.689 0.279 280 160 0.642 0.232 336 214 0.591 0.181 431 293 0.550 0.140 557 389 0.514 0.104 750 539 0.485 0.075 1040 686 0.479 0.069 1130 912 0.464 0.054 1444 (D 0.410 202 Table 103 o-Iodobenzoic Acid

Temp. 30° Conc, O.OIM Dilution l/50 Eo 5,950 Ejo 2,050 \ 241 mu. = 4.45

t(min. ) A A — Aoo l/c

0 1.190 0.780 100 5 1. 067 0.657 119 13 0.920 0.510 153 24 0.796 0.386 202 37 0,712 0.302 258 54 0.642 0.232 336 70 0.595 0,185 422 90 0.565 0.155 503 115 0.528 0.118 661 141 0.513 0.103 757 170 0.499 0.089 876 200 0. 484 0.074 1054

(D 0.410

Tab^e 104 o-Iodobenzoic Acid

Temp. 30® Conc. O.OIM Dilution l/5 0 Eo 5,950 Eflo 2,050 A 241 mu kg =4.25

t(min. ) A A — A q ) l / c

0 1.190 0.780 100 5 1.077 0.667 117 13 0. 917 0.507 154 24 0.806 0.396 197 37 0.727 0.317 246 54 0.653 0.243 321 70 0.600 0.190 411 90 0.576 0.166 470 115 0.536 0.126 619 141 0. 508 0. 098 796 170 0.495 0.085 918 200 0.481 0.071 1099 00 0.410 Z03 T able 105 o-Iodobenzoic Acid

Temp, 30® Conc, 0, OlM Dilution 1/50 Eo 5,950 E(d 2,050 \ 24lmu kj = 4.38

t(min. ) A A — A® l/c

0 1,190 0.780 100 5 1,078 0.668 117 13 0,932 0.522 149 24 0,798 0.388 201 37 0,717 0.307 254 54 0,647 0.237 329 70 0,600 0.190 411 90 0,567 0,157 467 115 0.539 0.129 605 141 0,513 0,103 757 170 0.500 0.090 867 200 0.485 0.075 1040 OD 0,410

Table 106 o-Iodobenzoic Acid

Temp, 25® Conc, 0,00333 Dilution 2/5 0 Eo 5,700 E@ 1,950 \ 241 mu kg = 2.52

t(m.in, ) A A - Aq) l/c

0 0,760 0,500 300 15 0,705 0.445 337 55 0.607 0.347 432 87 0.558 0.298 503 176 0,461 0.201 746 253 0.419 0,159 943 380 0.377 0,117 Î.280 710 0,332 0,072 2080 00 0,260 204 Table 107 o-Iodobenzoic Acid

Temp. 25° Conc, 0,00333 Dilution 2/50 Eo 5,700 Eg) 1,950 ^ 24lmu kg = 2,58

t(min. ) A A - Agg l/c

0 0.760 0,500 300 10 0,744 0,484 310 55 0.611 0,351 427 87 0. 560 0. 300 500 176 0.470 0,210 714 253 0,423 0,163 920 380 0. 379 0. 119 1260 710 0.341 0,081 1850 00 0. 260

Table 108 o-Iodobenzoic Acid

Temp, 25° Conc, 0 .00333M Dilution 2/50 Eo 5,700 E® 1,950 \ 241 mu kg = 2, 59

t(min, ) A A — A® l/c

0 0.760 0,500 300 14 0,715 0,455 330 55 0,600 0,340 440 87 0.553 0.293 512 176 0,461 0,201 746 253 0,412 0,152 985 380 0,386 0.126 1190 710 0,330 0,070 2140 00 0.260 205 T able 109 0 “Nitrobenzoic Acid

Temp. 10® Conc. O.OIM Dilution l/50 Eo 0 E(o 3,575 \ 41 Omu kz = 0.00960

t(mirL. ) A Ag) - A l/c

0 0 0.715 100.0 6 0. 002 0.713 100. 3 151 0.013 0.702 101.9 260 0.019 0.696 102.7 394 0. 028 0.687 104.1 540 0.037 0.678 105.5 723 0.048 0.667 107.2 860 0.057 0.658 108.7 1310 0. 081 0.634 112.8 1655 0. 099 0.616 116.1 1842 0.109 0.606 118.0 2230 0.125 0.590 121.2 m 0.715

Table 110 o-Nitrobenzoic Acid

Temp. 10® Conc. 0, OlM Dilution l/50 Eg 5,300 E® 12,250 229mu kg = 0.0097

t(min. ) A A® - A l/c

0 0 1.060 1,390 100. 0 6 1.069 1.381 100.7 151 1.085 1.365 101.8 260 1.096 1.354 102. 7 394 1.125 1.325 104.9 540 1.133 1.317 105.5 723 1.177 1.273 109.1 860 1.168 1.282 108.4 1310 1.232 1.218 114.1 1655 1.244 1.206 115.3 1842 1.285 1.165 119,3 2230 1.313 1.137 122.3 a 2.45 206 T able 111 o-Nitrobenzoic Acid

Temp. 10° Conc. 0. OlM Dilution l/50 Eo 0 E® 3,575 ^ 41 Omu kz = 0.00935

t(min, ) A A® - A 1/c

0 0 0.715 100. 0 6 0.002 0.713 100. 3 151 0.011 0.704 101.6 260 0.019 0.696 102.7 394 0. 0 28 0.687 104. 1 540 0.0 37 0.678 105.5 723 0.0 48 0.667 107.2 860 0.0 57 0.658 108.7 1310 0.0 81 0.634 112.8 1655 0.0 97 0.618 115.7 1842 0.1 07 0.608 117.6 2230 0.1 25 0.590 121.2 00 0.7 15

Table 112 o-Nitr obenz oic Acid

Temp, 10° Conc. 0, OlM Dilution 1/50 Eo 5,300 E® 12,250 229mu kz = 0. 0093

t(min, ) A Aqo - A 1/c

0 1.060 1.390 100.0 6 1.071 1.379 100.8 151 1,0 94 1.356 102.5 260 1. 0 92 1.358 102.4 394 1.1 22 1.328 104.7 540 1.1 39 1.311 106.0 723 1.1 64 1.286 108.1 860 1.1 75 1.275 109.0 1310 1.2 40 1.210 114.9 1655 1.247 1.203 115.5 1842 1.2 86 1.164 119.4 2230 1.310 1.140 121 .9 00 2.45 207 T able 113 o-Nitr obenz oic Acid

Temp. 10® Conc, O.OIM Dilution 1 /50 Eo 0 Eo, 3,575 ^ 41 Omu kz = 0.00930

t(min. ) A Aoo “ A l/c

0 0 0.715 100.0 6 0.0 02 0.713 100.3 151 0.011 0.704 101 .6 260 0.019 0.696 102 .7 394 0.0 27 0.688 103.9 540 0.037 0.678 105.5 723 0.047 0.668 107.0 860 0.0 55 0.660 108.3 1310 0. 0 80 0.635 112.6 1655 0.0 97 0.618 115.7 1842 0.1 06 0.609 117.4 2230 0.125 0.590 121 . 2 œ 0.715

Table 114 o-N itr obenz oic Acid

Temp. 10® Conc. 0. OlM Dilution 1/50 Eo 5,300 Em 12,250 \ 229mu kz = 0. 009

t(min, ) A Aoo ” A l/c

0 1.060 1.390 100.0 6 1, 0 66 1.384 100.4 151 1.089 1.361 102.1 260 1.0 94 1.356 102.5 394 1.1 il 1.339 103.8 540 1.1 50 1.300 106.9 723 1.165 1.285 108.2 860 1.176 1.274 109.1 1310 1.228 1.222 113.7 1655 1.250 1.200 115.8 1842 1.278 1.172 118.6 2230 1.317 1.133 122.7 00 2.45 208 T able 115 o-Nitr obenz oic Acid

Temp. 20° Conc, 0, OlM Dilution 1 /50 Eo 0 E® 3,575 \ 41 Omu kz = 0.032

t(min. ) A Aoo “ •A- lA

0 0 0.715 100.0 7 0. 003 0.712 100.4 28 0. 008 0.707 101 .1 90 0. 0 22 0.693 103.2 170 0. 0 38 0. 677 105.6 253 0.0 56 0. 659 108.5 368 0.0 77 0.638 112.1 517 0.1 03 0.612 116.8 629 0. 1 21 0.594 120.4 709 0.1 33 0.582 122.9 820 0.150 0.565 126.5 1300 0,2 10 0.505 141 .6 00 0.715

Table 116 o-Nitr obenz oic Acid

Temp, 20° Conc. 0, OlM Dilution 1 /50 Eo 5,300 Eq, 12,250 ^ 229mu kz = 0. 033

t(min, ) A A(d - A , 1/9 . _

0 1. 060 1.390 100.0 7 1. 0 62 1.388 100.1 28 1.0 68 1.382 100.6 90 1.0 98 1,352 102.8 170 1.1 38 1.314 105.8 253 1.168 1.282 108.4 368 1.217 1.233 112.7 517 1. 2 66 1.184 117.4 629 1.2 95 1.155 120. 3 709 1. 323 1.127 123.3 820 1.3 57 1.093 127.2 1300 1.458 0.992 140 .1 0 0 2.45 209 T a b le 117 o-Nitr obenz oic Acid

Temp, 20° Conc, 0, OlM Dilution 1/50 Eo 9 Eco 3,575 41 Omu kz = 0.032

t(min. ) A A® — A ...... V 9 . . . .

0 0 0,715 100, 0 7 0,0 03 0.712 100,4 28 0,0 08 0,707 101 , 1 90 0.023 0,692 103,9 170 0,0 40 0, 675 105,9 253 0,056 0,659 108.5 368 0,0 78 0,637 112,2 517 0.1 03 0.612 1 16.8 630 0,122 0.593 120. 6 709 0,1 35 0.580 123. 3 820 0,1 50 0,565 126.5 1300 0,212 0,503 142.1 00 0.715

Table 118 o-Nitr obenz oic Acid

Temp, 20° Conc. 0. OlM Dilution 1/50 Eo 5,300 E® 12,250 ^ 229mu kz = 0,033

t(min, ) A A® - A ... 1/S- ..

0 1,060 1.390 100. 0 7 1.069 1,387 100,2 28 1.079 1.371 101 .4 90 1.1 00 1.350 103. 0 170 1.1 33 1,317 105.5 253 1.1 78 1.272 109, 3 368 1.216 1.234 112,6 517 1.2 60 1.190 116.8 630 1*299 1,151 120.8 709 1,326 1.124 123.7 820 1.357 1*093 127.2 1300 1.476 0,974 142.8 00 2*45 210 T able 119 o-Nitrobenzoic Acid

Temp. 20° Conc. 0, OlM Dilution 1 /50 Eo 0 Eœ 3,575 \ 41 Omu kg = 0.031

t(min. ) A Ag) - A l/c

0 0 0.715 100.0 7 0.0 05 0.710 100.7 28 0.0 09 0.706 101 .3 90 0.0 22 0.693 103.2 170 0.0 39 0.676 105.8 253 0.0 54 b. 661 108.2 368 0.0 77 0.638 112.1 517 0.1 02 0.613 116.6 630 0.1 21 0.594 120.4 709 0.1 33 0.582 122.9 820 0.149 0.566 126.3 1300 0.212 0.503 142 .1 m 0.715

Table 120 o-Nitr «benz #ic Acid

Temp. 20° Conc. 0. OlM Dillution 1 /50 Eo 5,300 E@ 12,250 )y 229mu kg = 0. 032

t(min. ) A Ag) - A l/c

0 1.0 60 1.390 100.0 7 1.0 64 1.386 100.3 28 1.071 1.379 100.8 90 1.099 1.351 102.9 170 1.1 35 1.315 105.7 253 1.1 80 1.270 109.4 368 1.212 1.238 112.3 517 1.259 1.191 116.7 630 1.297 1.153 120.6 709 1.323 1.127 123. 3 820 1.351 1.099 126.5 1300 1.457 0.993 140.0 00 2.45 211 T a b le 121 o-Nitr obenz oic Acid

Temp, 30® Conc, 0. OlM Dilution l/50 Eo 0 Efl> 3,575 ^ 41 Omu kz = 1.101

t(min, ) A A® -, A l/c

0 0 0,715 100,0 5 0,0 03 0.712 100,4 25 0,0 18 0,697 102,6 55 0,0 39 0,676 105.8 77 0,0 53 0,662 108,0 100 0,0 67 0,648 110,3 125 0.0 82 0,633 113,0 160 0.1 01 0.614 116.4 200 0,1 19 0,596 120,0 240 0.1 39 0.576 124.1 290 0,1 63 0.552 129,5 350 0,1 91 0.524 136.5 00 0,715

Table 122 o-Nitr obenz oic Acid

Temp, 30° Conc, 0, OlM Dilution 1 /50 Eo 5,300 Ero 12,250 ^ 229mu kz = 0,100

t(min, ) A A® - A l/c

0 1,060 1,390 100,0 5 1.069 1.381 100,7 25 1.094 1.356 102,5 55 1,1 33 1.317 105,5 77 1,171 1,279 108,7 100 1,1 85 1,265 109,9 125 1,2 07 1,243 111,8 160 1.251 1.199 115.9 200 1,288 1.162 119,6 240 1,338 1.112 125,0 290 1,3 71 1.079 128.8 350 1,421 1.029 135.1 00 2,45 212 Table 123 o-Nitr obenz oic Acid

Temp, 300 Conc, 0, OlM Dilution 1/50 Eo 0 Eoo 3,575 41 Omu kg = 0,101

t(min. ) A A® - A l/c

0 0 0,715 100,0 5 0, 0 04 0.711 100, 6 25 0,019 0.696 102.7 55 0. 0 40 0,675 105.9 77 0.0 54 0.661 108.2 100 0,0 68 0.649 110.2 125 0. 0 83 0.632 113.1 160 0, 1 02 0.613 116,6 200 0,1 22 0.593 120,6 240 0, 140 0,575 124.3 290 0.1 91 0,551 129,8 00 0,715

Table 124 o-Nitr obenz oic Acid

Temp. 30° Conc. 0, OlM Dilution 1 /50 Eo 5,300 E(d 12,250 \ 229mu kg = 0. 098

t(min. ) A A® - A ...... A /c......

0 1,0 60 1.390 100.0 5 1.077 1.376 101 ,0 25 1.099 1,351 102,9 55 1.1 38 1.312 105.9 77 1.1 81 1.269 109,5 100 1.1 94 1.256 110.7 125 1.217 1.233 112.7 160 1.2 61 1.189 116.9 200 1.3 02 1,148 121.1 240 1.3 34 1.116 124.6 290 1.3 72 1,078 128.9 œ 2.45 213 T able 125 o-Nitrobenzoic Acid

Temp. 30° Conc. 0. OlM Dilution 1 /50 Eo 0 Eo, 3,575 ^ 41 Omu kz = 0.1040

t(min, ) A A{d — A l/c

0 0 0.715 100.0 5 0.0 03 0,712 100.4 25 0.019 0.696 102.7 55 0.0 44 0.671 106, 6 77 0.056 0.659 108.5 100 0.0 70 0.647 110.5 125 0. 0 83 0.632 113.1 160 0. 1 02 0.613 116.6 200 0.124 0.592 120.8 240 0.142 0.573 124.8 290 0.167 0.548 130.5 350 0.192 0.523 136.7 m 0.715

Table 126 o-Nitr obenz oiic A cid

Temp. 30° Conc. 0, OlM Dilution 1/50 Eo 5,300 Eod 12,250 \ 229mu kg = 0.1068

t{inin, ) A A(d - A l/c

0 1.060 1.390 100.0 5 1.072 1.378 100.9 25 1.122 1.328 104.7 55 1.141 1.309 106.2 77 1.188 1.262 110.1 100 1.202 1.248 111 .4 125 1.220 1.230 113.0 160 1.276 1.174 118.4 200 1.320 1.130 123.0 240 1.3 42 1.108 125.5 290 1.398 1.052 132.1 350 1.435 1.015 136.9 00 2.45 214 T able 127 o-Nitr obenz oic Acid

Temp, 25° Conc, O.OIM Dilution 3/100 E o 0 E(b 3.000 ^ 41 Omu kg = 0. 06l

t(min, ) A Afl) - A l/c

0 0 0,900 100,0 8 0.0 05 0,895 100,5 70 0.0 38 0,862 104, 3 135 0,0 69 0,831 108,2 215 0,1 05 0,795 113,1 305 0,144 0.756 119,0 440 0.194 0.706 127,4 560 0.2 32 • 0,668 134,7 670 0,2 63 0,637 141,0 810 0,2 99 0.601 149, 5 1245 0,3 85 0,515 174,7 1725 0,4 55 0,445 202. 0 2255 0,515 0,385 233, 0 2950 0.5 67 0,333 270,0 3620 0,6 05 0,295 306,0 5650 0,6 80 0.217 415, 0 00 0,9 00 215 Table 128 o-Nitr obenz oic Acid

Temp, 25° Conc. 0, OlM Dilut ion 3/100 Eo 0 E® 3,000 \ 41 Omu kg = 0 .06l

t(min, ) A A® - A l / c

0 0 0.900 100.0 8 0.0 07 0.893 100.6 70 0.038 0.862 104.3 135 0.0 69 0.831 108.3 215 0.1 06 0.794 113.1 305 0.144 0.756 119.0 440 0.195 0.705 127.5 560 0.2 32 0,668 134.3 670 0.2 62 0.638 140.8 810 0.3 02 0.598 150.3 1245 0.3 86 0.514 174.6 1725 0.456 0.444 203.0 2255 0.516 0.384 234.0 2950 0.5 69 0.331 271 .0 3620 0.6 07 0.300 300.0 5650 0.6 84 0.223 412.0 œ 0.9 00 216 Table 129 o-Nitr obenz oic Acid

Temp, 25° Conc, 0, OlM Dilut ion 3/100 Eo 0 Eq) 3,000 J\ 41 Omu kg = 0. 06C

t(min. ) A A(d - A l/c

0 0 0.900 100,0 8 0.0 05 0.895 100.5 70 0.0 39 0.861 104.4 135 0.0 69 0.831 108.2 215 0.1 05 0.795 113.1 305 0.143 0.757 119.0 440 0.1 92 0.708 127.0 560 0.2 30 0.670 134.2 670 0.2 62 0.638 140.8 810 0.2 95 0.605 148.9 1245 0.3 83 0.517 174.0 1725 0.4 53 0,447 201 .0 2255 0.5 05 0.395 228.0 2950 0.5 57 0.343 263.0 3620 0.6 00 0.307 293.0 5650 0.6 78 0.229 394.0 00 0.9 00 . 217 Table 130 Phtbalic Anhydride

Temp. 20° Conc. 0 .05M Dilution 1/500 Eo 7,450 E(o 10. 900 \ 222mu kz = 0.001

t(min, ) A A — Afl) . lA ....

0 0. 7 45 0.345 20. 00 5 0.7 49 0.341 20. 23 100 0.7 54 0.336 20. 54 182 0.7 55 0.335 20. 60 339 0.7 59 0.331 20. 85 410 0.7 65 0.325 21. 23 688 0.7 68 0.322 21. 43 880 0.7 70 0.320 21. 56 1828 0.7 91 0.299 23. 08 2290 0.8 02 0.288 23. 96 3092 0.8 07 0.283 24. 38 m 1.090

Table 131 Phthalic Anhydride

Temp, 20° Conc. 0 ,05M Dilution 1 /500 Eo 7,450 Eœ 10, 900 ^ 222mu kz = 0. 001

t(min, ) A A — Afl) l/c

0 0.7 45 0.345 20. 00 5 0.7 46 0.344 20. 06 100 0.7 52 0.338 20. 41 262 0.7 55 0.335 20. 60 410 0.7 59 0.331 20. 85 688 0.7 62 0.328 21. 04 880 0.7 67 0.323 21. 36 1828 0,7 84 0.306 22. 55 2290 0.8 01 0.289 23. 88 3092 0.8 07 0.283 24. 38 00 1.0 90 218 Table 132 Phthalic Anhydride

Temp, 20° Conc. 0.05M Dilution 1/500 Eo 7,450 Eo, 10. 900 \ 222mu kz = 0. 0015

t(min, ) A Aoo - A l/c

0 0.745 0.345 20. 00 5 0.7 54 0.336 20. 54 100 0.7 54 0.336 20. 54 182 0.7 47 0.343 20. 12 339 0.7 64 0.326 21. 17 410 0.7 65 0.325 21. 23 688 0.7 67 0.323 21. 36 880 0.7 93 0.297 23. 23 1828 0.8 00 0.290 23. 79 2290 0.8 04 0.286 24. 13 3092 0.8 07 0.283 24. 38 00 1.0 90

Table 133 Phthalic Anhydride

Temp. 30° Conc. 0.05M Dilution 1/500 Eo 7,450 Effl 10. 900 222mu kz = 0.0060

t(min, ) A Aq 0 “ a ...... _

0 0.7 45 0.345 20. 00 4 0.7 49 0.341 20. 23 21 0.7 54 0.336 20. 54 54 0.7 56 0.334 20. 66 93 0.7 60 0.330 20. 91 126 0.7 63 0. 327 21. 10 173 0.7 68 0.322 21. 43 222 0.7 72 0.318 21. 70 355 0.7 80 0.310 22. 26 494 0,7 94 0.296 23. 31 676 0.8 07 0.283 24. 38 00 1.090 219 Table 134 Phthalic Anhydride

Temp, 30° Conc. 0.05M Dilution 1/500 Eo 7,450 Eœ 10, 900 \ 222mu kz = 0. 00548

t(min, ) A A(d A l/c

0 0.7 45 0.345 20. 00 4 0.7 51 0.339 20. 35 21 0.7 57 0.333 20. 72 54 0.7 59 0.331 20. 85 93 0.7 62 0. 328 21. 04 126 0.7 66 0.324 21. 30 173 0.7 72 0.318 21. 70 222 0.7 73 0.317 21. 77 355 0.7 80 0.310 22. 26 494 0.7 95 0.295 23. 39 676 0.8 04 0.286 24. 13 9 1.090

Table 135 Pth ali c Anh ydride

Temp. 30° Conc. 0.05M Dilution 1/500 Eo 7,450 E(o 10. 900 \ 222mu kz = 0.00568

t(min, ) A Aflj - A l/c

0 0.745 0.345 20. 00 4 0.7 52 0.338 20. 41 21 0.7 54 0.336 20. 54 54 0.7 57 0.333 20. 72 93 0.7 62 0.328 21. 04 126 0.7 66 0.324 21. 30 173 0.7 72 0.318 21. 70 222 0.7 76 0.314 21. 97 355 0.7 81 0.309 22. 33 494 0.7 89 0.301 22. 92 676 0.8 07 0.283 24. 38 (D 1.0 90 220 Table 136 2, 5 -D im ethylbenzoic A cid.

Temp. 10° Coac, 0. OlM Dilution 1/50 ^max. Eod 50 \ 234. 5mu kz = 0.582

t(min. ) A A “ Afl) l/c

0 1.310 1.300 100 3 1.267 1.257 103 14 1.185 1.175 111 26 1.121 1.111 117 51 0.9 87 0.977 133 81 0.8 84 0.874 149 114 0.7 70 0,769 169 162 0.674 0. 664 196 224 0.5 64 0.554 235 303 0.486 0.476 273 a 0.010

Table 137 2, 5 -D im ethylbenzoic A cid

Temp, 10° Conc. O.OIM Dilution l/50 ^max, Efl, 50 234.5mu kg = 0, 570

t(min, ) A A - Afl) l/c

0 1.310 1.300 100 3 1.2 62 1.252 104 14 1.1 86 1.176 111 26 1.113 1,103 118 51 0,9 93 0.983 132 81 0.8 79 0.869 150 114 0.7 84 0.774 168 162 0.6 77 0.667 195 224 0.5 75 0,565 230 303 0.4 81 0,471 276 00 0.010 221 Table 138 2,5 -D im ethylbenzoic Acid

Temp, 10® Conc. 0. OlM Dilution 1 /50 Emax, 6,550 E(D 50 ^ 234,5mu kg = 0,572

t(mia, ) A A - A(d l/c

0 1.310 1.300 100 3 1.289 1.279 102 14 1.210 1.200 108 26 1.1 23 1.113 119 51 1.013 1.003 130 81 0.8 84 0.874 149 114 0.7 90 0.780 167 162 0.684 0.674 193 224 0,5 78 0.568 229 303 0.4 89 0.479 271 (D 0.010

Table 139 2,5 -D im ethylbenzoic Acid

Temp. 20® Conc. 0. OlM Dilution 1 /50 ^max, E(o 50 \ 234,5mu kg = 1.80

t(min, ) A A “ A{j) l/c

0 1.310 1,300 ' 100 3 1.2 24 1,214 107 7 1.157 1.147 113 13.5 1.018 1.008 129 34 0.8 02 0.792 164 48 0.7 03 0.693 188 67 0.5 79 0.569 228 96 0.4 87 0.477 273 120 0.419 0.409 318 165 0.3 37 0.327 398 m 0. 010 222 Table 140 2, 5 -D im ethylbenzoic A cid

Temp, 20° Conc. 0, OlM Dilution 1 /50 Siinax. 6,550 Efl, 50 ^ 234,5mu k2 = 1.84

t(min. ) A A - A® l/c

0 1,310 1.300 100 3 1,2 07 1.197 109 7 1.140 1.130 115 14 1,025 1.015 128 34 0.8 04 0.794 164 48 0.6 97 0.687 189 67 0,5 84 0.574 226 96 0,475 0.465 280 120 0,413 0.403 323 165 0,3 30 0.320 406 oo 0.010

Table 141 2,5 -D im ethylbenzoic A cid

Temp, 20° Conc, 0, OlM Dilution 1/50 Emax, 6,550 Eco 50 234,5mu kz = 1.815

t(min. ) A A — A® l/c

0 1.310 1.300 100 3 1,216 1.206 108 7 1,149 1,139 114 14 1,0 24 1.014 128 34 0,8 04 0.794 164 48 0,6 98 0.688 189 67 0,5 85 _ 0.575 226 96 0,483 0.473 275 120 0.415 0.405 321 165 0,3 34 0.324 401 OD 0,010 223 Table 142 2, 5 -D im ethylbenzoic A cid

Temp, 30° Conc, O.OIM Dilution 1 /50 Etnax. 6,550 Eqj 50 234.5mu kg = 5,43

t(min. ) A A — A® l/c

0 1,310 1.300 100 3.0 1,170 1.160 112 5.8 1.021 1.011 129 10.2 0.8 54 0.844 154 15.5 0.726 0.716 182 21.1 0.6 23 0.613 212 27.0 0.5 39 0.529 246 34. 1 0.4 67 0.457 284 43.4 0.399 0.389 334 56. 1 0.3 33 0.323 402 71.1 0.2 76 0.266 489 m 0.010

Table 143 2, 5 -D im ethylbenzoic A cid

Temp, 30° Conc, O.OIM Dilution 1/50 E 6,550 d A 234.5mu kg = 5.45 max. * E( 50

t(min, ) A A — A® _l/c

0 1,310 1.300 100 2.8 1.139 1.129 115 5.9 0.9 90 0.980 133 10.4 0.8 34 0.824 158 15.5 0,7 17 0.707 184 21,0 0 .610 0.600 217 26.9 0,5 33 0.523 249 34.2 0.4 60 0.450 289 43.4 0.3 94 0.384 339 56.1 0.3 30 0.320 406 71.0 0.2 78 0.268 485 m 0.010 224 Table 144 2, 5 -D im ethylbenzoic A cid

Temp. 30° Conc. O.OIM Dilution l/50 ^max, 6,550 Efl, 50 ^ 234,5mu kg = 5.48

t(min, ) A A — Aflj l/c

0 1,310 1.300 100 2,8 1.1 19 1.109 117 6.3 0.9 73 0.963 135 10,6 0.8 26 0.816 159 15.9 0.6 98 0.688 189 21,1 0.611 0.601 216 26.7 0.5 33 0.523 249 34.1 0.459 0.449 290 43.7 0.3 94 0.384 339 56.2 0.3 36 0.326 399 70.90 0.2 78 0.268 485 00 0.010

Table 145 2, 3 -D im ethylbenzoic A cid

Temp. 10° Conc, O.OIM Dilution 1/50 ^max, Effl 250 234mu kg = 3.09

t(min. ) A A — Aq) l/c

0 1.050 1.000 100 5 0.852 0.802 125 21 0.6 02 0.552 181 36 0.4 99 0.449 223 50 0.427 0.377 265 70 0.3 59 0.309 324 100 0.2 88 0.238 420 133 0.2 35 0.185 514 171 0.1 95 0.145 690 220 0.172 0.122 820 00 0.0 50 225 Table 146 2, 3-Dimethylbenzoic Acid

Temp, 10° Conc, O.OIM Dilution l/SO Eznax. 5,250 Eod 250 ^ 234mu kg = 3.11

t(rtiin. ) A A - Ajd 1/c

0 1,050 1.000 100 6 0.815 0.765 131 21 0.5 99 0.549 182 36 0.493 0.443 226 50 0,423 0.373 268 70 0.3 56 0.306 327 100 0,2 89 0.239 418 134 0,2 43 0.193 518 171 0.2 06 0.156 641 220 0.173 0.123 813 00 0.050

Table 147 2, 3 -D im ethylbenzoic A cid

Temp. 10° Conc, O.OIM Dilution 1 /50 ^max, 5,250 Em 250 234mu kg = 3.06

t(min, ) A A - A(d 1/c _ _

0 1,050 1,000 100 6 0,8 29 0,779 128 21 0.6 23 0,573 175 36 0,5 12 0.462 216 50 0.4 30 0.380 263 70 0.3 68 0.318 314 100 0.2 89 0.239 418 134 0,2 36 0.186 538 171 0,2 05 0.155 645 220 0.1 71 0.121 826 00 0,0 50 226 Table 148 2, 3 -D im ethylbenzoic A cid

Temp, 20° Conc. O.OIM Dilution 1/50 Emax. 5.250 Efl, 250 234mu kz = 8. 79

t(min, ) A A “ Aq) l/c

0 1.0 50 1.000 100 3.5 0.7 75 0.725 138 8.5 0. 6 00 0.550 182 14.0 0.4 87 0.437 229 21.5 0. 3 78 0.328 305 29.0 0. 3 22 0.272 368 38.0 0.2 70 0.220 455 43.5 0.2 58 0.208 481 52.0 0.2 28 0.178 562 65.0 0.1 95 0.145 690 82.0 0.172 0.122 820 100.0 0.1 50 0.100 1000 0 0 0.0 50

Table 149 2, 3 -D im ethylbenzoic Acid

Temp. 20° Conc. O.OIM Dilution 1 /50 5-^50 Eœ 250 ^ 234mu kg — 8. 82

t(min, ) A A - A(j) l/c

0 1.050 1.000 100 3.5 0.7 63 0.713 140 9 0.5 88 0.538 186 14 0.485 0.435 230 21 0.3 92 0.342 292 29 0.3 26 0.276 362 38 0.2 71 0.221 452 52 0.2 28 0.178 562 65 0.1 97 0.147 680 82 0.1 69 0.119 840 100 0.147 0.097 1031 00 0.0 50 227 T able 150 2, 3 -D im ethylbenzoic A cid

Temp. 20° Conc. 0, OlM Dilution 1 /50 ^max, 5,250 Ea, 250 \ 2 34mu kg = 8.80

t(min, ) A A - A

0 1. 050 1.000 100 3.5 0.7 29 0.679 147 9 0.5 65 0.515 194 14 0.470 0.420 238 21 0.3 83 0.333 300 29 0,318 0.268 373 39.5 0.2 67 0.217 461 52 0,2 28 0.178 562 65 0.1 96 0.146 685 82 0,176 0.120 833 ^00 0.1 50 0.100 1000 m 0.050

Table 151 2,3 -D im ethylb enzoic A cid

Temp. 30° Conc. 0. OlM Dilution 1 /50 5,250 Eco 250 234mu kg = 22.2

t(min. ) A A - Afl) l/c

0 1.050 1.000 100 2.6 0.672 0.622 l6l 5.2 0.4 99 0.449 223 8.3 0.3 92 0.342 292 11.8 0.3 25 0.275 364 16.0 0,2 70 0.220 455 21.2 0.2 27 0.177 565 26.9 0.1 96 0.146 685 34.1 0.173 0.123 813 42.8 0,1 51 0.101 990 54.6 0.1 34 0.084 1190 68.6 0.123 0.073 1370

CD 0.0 50 228 T able 152 2, 3 -D im eth ylb en zoic A cid

Temp. 30° Conc, O.OIM Dilution 1/50 Emax. 5,250 Eo) 250 \ 234mu kg = 22.2

t(min, ) A A - Ajq l/c

0 1.050 1.000 100 3.0 0.7 59 0.709 141 5.5 0.5 49 0.499 200 8.6 0.4 22 0.372 269 11.8 0.3 44 0.294 340 15.9 0.2 82 0.232 431 21.4 0.2 33 0.183 546 26.9 0.1 98 0.148 676 34.0 0.1 73 0.123 813 42.9 0.1 53 0.103 971 54.8 0.1 35 0.085 1176 68.7 0.122 0.072 1389 ca 0. 050

Table 153 2, 3 -*D im ethylbenzoic A cid

Temp. 30° Conc. O.OIM Dilution 1/50 Emax. 5,250 Efl, 250 ^ 234mu kg = 21.2

t(min. ) A A - Ajq l/c

0 1.050 1.000 100 4.0 0. 6 09 0.559 179 6.7 0.467 0.417 240 9.8 0.3 73 0.323 310 13.0 0.316 0.266 376 17.9 0.2 53 0.203 493 22.6 0.218 0.168 595 28.2 0.1 88 0.138 725 35.5 0.1 66 0.116 862 44.0 0.1 50 0.100 1000 54.8 0.1 32 0.082 1220 68.8 0.119 0.069 1449 (D 0.0 50 229 Table 154 2, 4 -D im ethylbenzoic A cid

Temp. 10° Conc, O.OIM Dilution 1 /lOO Emax. 10,20 0 E® 300 \ 242mu kz = 0.529

t(min, ) A A — Ajd l/c

0 1.020 0.990 100 3 0.9 95 0.965 103 26 0.8 85 0,855 116 57 0.7 68 0.738 134 94 0.6 80 0.650 152 144 0.5 75 0.545 182 203 0.5 00 0,470 211 284 0.4 22 0,392 252 350 0.3 75 0.345 287 œ 0.0 30

Table 155 2,4 -D im ethylbenzoic Acid

T emp, 10° Conc. O.OCM Dilution 1 /lOO Exnax. ^ 0.20 0 Eœ 300 \ 242mu kz = 0.532

t(min, ) A A - A® l/c

0 1.020 0.990 100 3 0.9 87 0.957 103 26 0.8 83 0.853 116 57 0.7 84 0,754 131 94 0.6 87 0.657 151 144 0.5 85 0.555 179 203 0.4 99 0.469 211 284 0.4 21 0.391 253 350 0. 3 74 0.344 288 OD 0. 0 30 230 T a b le 156 2,4 -D im ethylbenzoic A cid

Temp. 10° Conc. 0. OlM Dilution l/lOO Emax. 10,200 Ea, 300 \ 242mu kg = 0.544

t(min, ) A A - Aq, l/c

0 1.020 0.990 100 3 1.000 0.970 102 26 0.8 91 0.861 115 57 0.7 81 0.751 132 94 0.6 91 0.661 150 144 0.5 84 0.554 179 203 0.5 01 0,471 210 284 0.418 0.388 255 350 0.3 68 0.338 293 m 0. 0 30

TablA 157 2,4 -D im ethylb enzoic A cid

Temp, 20° Conc. 0. OlM Dilution 1 /lOO Emax. 10.200 Ea, 300 \ 242mu kg = 1.71

t(min. ) A A - Aju y/9._____

0 1.0 20 0.990 100 5 0.925 0.895 111 13 0.8 41 0.811 122 27 0.7 08 0.678 146 43 0.6 02 0.572 173 61 0.4 95 0.465 213 87 0.4 33 0.403 246 120 0.3 55 0. 325 305 163 0.3 21 0.266 373 200 0.2 61 0.231 429

OD 0.0 30 231 T able 158 2, 4 «D im ethylbenzoic A cid

Temp. 20° Conc. O.OIM Dilution l/lOO Ernax. 10,20 0 E(o 300 ^ 242mu kg = 1.71

t(min, ) A A — Aflo lA .

G 1.020 0.990 100 5 0.9 42 0.912 109 13 0.8 57 0.827 120 27 0.7 24 0. 694 143 43 0.6 07 0.577 172 61 0,5 03 0.473 209 87 0.4 31 0.401 247 120 0.3 57 0.327 303 163 0.2 96 0.266 372 200 0.2 60 0.230 430 (D 0.0 30

Table 159 2,4 -D im ethylbenzoic A cid

Temp, 20° Conc, 0. OlM Dilut ion 1 /l 0 0 ^max, 10,20 0 Eq, 300 ^ 242mu kz = 1.71

t(min. ) A A - Aflo 1/c

9 1.020 0.990 100 5 0. 9 26 0.896 110 12 0.8 43 0.813 122 26 0.717 0.687 144 42 0.6 05 0,575 172 60 0.4 95 0.465 213 86 0.430 0.400 248 119 0.355 0.325 305 162 0. 2 95 0.265 374 200 0.2 57 0.227 436 GO 0. 0 30 232

Table 160 Benzoic Acid

Temp. 20° Conc, 0,05M Dilution 1/500 ^max, 11 » 10 0 ^ 230mu kz = 0.0070

t(m in, ) A 1/c

0 1,1 10 20, 0 1 5 1, 1 03 20. 1 11 9 1,058 21, 0 30 2 1,006 22. 1 41 5 0,9 53 23, 3 59 0 0.9 23 24. 1 915 0,8 58 25, 9 1390 0.750 29. 6 223 0 0,6 20 35, 8 307 5 0,5 39 41, 2

Table l6l Benzoic Acid

Temp, 20° Conc, 0.05M Dilution l/SOO E 11,100 X 230mu kz = 0,00705 max. /\ t(m in, ) A 1/c

0 1, 1 10 20. 0 9 1,098 20. 2 11 0 1,070 20. 8 29 3 1.0 05 22. 1 40 6 0,9 55 23. 2 58 0 0,9 30 23. 9 90 8 0,8 55 26. 0 138 0 0,7 48 29, 7 222 0 0,619 35, 9 306 5 0,5 34 41. 6 233 T able 162 Benzoic Acid

T emp. 20® Conc. 0 ,05M Dilution 1/500 Exnax. 230 mu kz = 0,006 85

t(min. ) A 1/c

0 ' 1.1 10 20. 0 7 1.1 08 20. 0 11 0 1.0 63 20. 9 29 0 1.028 21. 6 405 0.9 58 23. 2 58 0 0.9 41 23. 6 91 0 0,8 63 25. 7 1380 0.7 57 29. 3 222 0 0.6 27 35. 4 306 0 0.5 41 41. 1

Table 163 Benzoic Acid

Temp. 30® • Conc, 0 .05M Dilution 1/500 Exnax. ^ 230 mu kz = 0.024 4

t(min. ) A 1/c

0 1.1 10 20. 0 6 1.1 05 20. 1 33 1.0 96 20.3 89 1.0 04 22. 1 152 0.9 34 23. 7 253 0.8 47 26. 2 334 0.7 93 28. 0 445 0.7 21 30. 8 625 0.6 31 35. 2 782 0.5 68 39. 1 960 0.5 31 41. 8 1425 0.419 53. 0 234 T able l6 4 Benzoic Acid

Temp. 30° Conc. 0 .05M Dilution 1 /500 Exnax. ^ 230 mu kz = 0.024 8

t(m in, ) A 1/c

0 1.1 10 20. 0 5 1.1 10 20. 0 32 1.0 87 20. 4 88 1.009 22. 0 151 0.9 32 23. 8 252 0.8 52 26. 1 333 0.7 78 28. 5 443 0.7 27 30. 5 623 0.6 29 35. 3 781 0.5 69 39. 0 960 0.5 30 41. 8 1425 0.419 53. 0

Table l65 Benzoic Acid

Temp. 30° Conc. 0 .05M Dilution 1/500 ^max. 11*10 0 ^ 230 mu kz = 0.0246

t{m in. ) A 1/c

0 1.1 10 20, 0 5 1.1 10 20, 0 33 1.093 20. 1 89 1.0 11 22. 0 153 0.9 38 23. 7 253 0.8 48 26. 2 337 0.7 86 28. 3 446 0.7 20 30. 8 625 0.6 27 35. 4 782 0.5 71 38. 9 960 0.5 22 42. 5 1430 0.418 53. 0 235 Table l66 Benzoic Acid

Temp, 40® Conc,, 0.05M Dilution 1 /500 ^max, 11*10 0 A 230 mu kz = 0.084

t(m in, ) A l / c

0 1.110 20. 0 5 1.1 06 20. 1 12 1.068 20. 8 41 0.9 36 23. 7 70 0.8 59 25. 8 111 0.7 54 29. 5 177 0.644 34. 5 257 0.5 39 41. 2 317 0.483 45. 9 392 0.4 33 51.2 545 0.3 58 62. 0

Table 167 Benzoic Acid

Temp. 40° Conc,, 0.05M Dilution 1 /500 Emax. 0 A 230 mu kz = 0.80

t(m in, ) A l/c

0 1.110 20. 0 8 1.0 87 20, 2 19 1.012 21. 9 41 0.9 37 23. 7 70 0.857 25, 9 111 0.745 29. 8 177 0.6 42 34. 6 257 0.5 42 41, 0 317 0.487 45. 6 392 0.4 32 51. 3 545 0.3 61 61. 5 236 T ab le 168 Benzoic Acid

Temp, 40® Conc. 0.0 5M Dilution l/S 0 0 Exnax. ^ 230mu kz = 0.078

t(min, ) A 1/c

0 1.110 20.0 4 1.098 20.2 16 1.048 21.2 44 0. 940 23.6 72 0.861 25.8 111 0.762 29.1 178 0. 647 34.3 260 0.551 40.3 318 0.497 44.7 393 0.437 50.8 545 0.368 60.4

Table 169 m-Toluic Acid

Temp, 20® Conc, 0,05M Dilution l/SOO Emax. 10,100 ^ 234mu kz = 0,0115

t(min. ) A 1/c

0 1.010 20.00 3 1.003 20.10 55 0.953 21.20 152 0.905 22.30 244 0. 873 23.14 322 0.845 23.90 417 0.802 25.20 500 0.778 26.00 729 0.709 28.50 980 0. 635 31.80 1780 0.500 40.40 2310 0.431 46.90 3233 0. 355 56.90 237 T ab le 170 m-T oluic Acid

Temp, 20° Conc. 0 ,05M Dilution l/SOO ^max, 10,100 \ 234mu kg = 0. 01135

t(min. ) A . l/c

0 1.010 20 4 1.001 20.2 36 0.961 21.0 133 0.914 22.1 225 0.883 22.9 303 0.853 23.7 398 0.809 25.0 481 0.789 25.6 712 0.719 28.1 962 0.639 31.6 1762 0.505 40.0 2290 0.432 46.8 3210 0.355 56.9

Table 171 m-T oluic Acid

Temp, 20° Conc. 0.05M Dilution 1/500 Emax. 10-100 234mu kg = 0.0114

t(min. ) A l/c

0 1.010 20 2 1.000 20.2 25 0.980 20.7 122 0.930 21.7 214 0.889 22.7 293 0.862 23.4 388 0.817 24.7 473 0.787 25.7 700 0.714 28.3 950 0.652 31.0 1750 0,511 39.5 2280 0.438 46.1 3200 0.354 57.1 238 T able 172 m -Toluic Acid

Temp, 30° Conc, 0 .05M Dilution 1/500 Exnax. 10.100 \ 234mu kz = 0.0412

t(min. ) A l/c

0 1. 010 20 4 1, 003 20.2 36 0.961 21,1 75 0,878 23.1 127 0,824 24.7 168 0,770 26.4 262 0,660 30,7 480 0,517 39.3 620 0.448 45,3 740 0, 405 50.2 520 0,269 75.5

Table 173 m -Toluic Acid

Temp. 30° Conc, 0 ,05M Dilution 1/500 ^max, 10,100 ^ 234mu kz = 0.048

t(min. ) A l/c

0 1,010 20 6 1,006 20,1 41 0,946 21,5 82 0,875 23,2 136 0,794 25.6 207 0,724 28.0 283 0, 636 32,0 491 0,518 39,2 626 0, 448 45,3 755 0,412 49,3 1530 0,268 75,8 239 T ab le 174 m -T olu ic A cid

Temp, 30® Conc, 0,05M Dilution 1/500 max. 10,100 \ 234mu kz = 0,0406

t(min, ) A 1/c

0 1,010 20 8 1,007 20.1 50 0.936 21.7 106 0,838 24.2 152 0.781 26,0 215 0.702 28,9 298 0,637 31,9 506 0,514 39,5 737 0.418 48,6

Table 175 m - T oluic Acid

Temp, 40® Conc, 0 ,05M Dilution 1/500 ^max. 10,100 ^ 234mu kz — 0,128

t(miu,) A 1/c

0 1,010 20 6 0,962 20.8 21 0,867 23.1 47 0.755 26.5 71 0, 671 29,8 102 0, 610 32,8 137 0, 528 37,9 189 0,447 44,7 258 0,383 52,2 300 0.358 55,8 352 0,318 62,9 240 Table 176 m. -Toluic Acid

Temp, 40° Conc,. 0 .05M Dilution 1/500 ^max. 10,100 A 234mu Kz = 0.126

t(min. ) A l/c

G 1.010 20 .6 0.962 20.8 20 0.882 22.7 46 0.765 26.1 70 0, 680 29.4 101 0. 610 32.8 138 0.525 38,1 188 0.455 44.0 257 0,390 51.3 300 0. 360 55.6 351 0. 322 62.2

Table 177 m -Toluic Acid

Temp, 40° Conc,. 0,05M Dilution 1/500 Emax, 10,100 A 234mu kz = 0.127

t(min. ) A l/c

0 1.010 20 5 0. 960 20.9 19 0.890 22,5 46 0.770 26,0 70 0.686 29.2 102 0. 614 32,1 138 0, 526 38,0 189 0,460 43.5 258 0, 393 50.9 301 0, 353 56,7 351 0,332 60.3 241 T able 178 m -T oluic Acid

Temp, 40® Conc, 0 ,05M Dilution 1/500 ‘P' 10,100 \ 234mu kg = 0. 128

t(mm, ) A l/c

0 1.010 20 3 0,993 20,2 8 0,943 21.2 20 0,878 22,8 47 0,775 25,8 75 0, 667 30,0 108 0.580 34,5 144 0, 530 37,7 173 0,480 41,7 207 0, 428 46,7 247 0,397 50.4

Table 179 m - T oluic Acid

Temp, 50° Conc, 0.05M Dilution 1/500 ^max. 10,100 ^ 234mu kg = 0.376

t(min. ) A l/c

0 1,010 20 1.6 0.962 20,8 10,5 0,820 24,4 1 6 ,2 0,762 26,2 28,0 0, 646 31.0 38,7 0,574 34,8 53,2 0,490 40,8 75,6 0.416 48,1 94,0 0,365 54,8 242 Table 180 m -Toluic Acid

Temp, 50° Conc, 0.05M Dilution 1/500 Emax. 10,100 \ 234mu kz = 0.380

t(min, ) A l/c

0 1,010 20 2.2 0,942 21.2 9.7 0, 842 23.8 19.6 0,710 28.2 26.3 0,657 30.4 39.3 0,564 35,5 51.4 0,500 40.0 64.8 0,449 44.5

Table 181 m -T oluic Acid

Temp, 50° Conc, 0.05M Dilution 1 /5 0 0 ^ 234mu kz = 0. 390

t(min. ) A l/c

0 1,010 20 2.5 0,955 20.9 5.8 0, 897 22.3 17.6 0. 738 27.1 31.7 0,612 32.7 40.9 0,557 35.9 50.9 0,505 39.6 66.5 0,447 44.7 89.0 0,378 52.9 243 Table 182 m -T oluic A cid

Temp* 50° Conc, 0,05M Dilution 1/500 ^max, lOolOO \ 234mu k% “ 0,384

t{min,. ) A l/c

0 1,010 20 4 0. 976 20.5 9 0.926 21.6 19 0. 775 25.8 37 0,604 33.1 48 0, 540 37.1 81 0,406 49.3 92 0.389 51.4 194 0. 237 84,4

Table 183 ^ oluic Acid

Temp, 20° Conc. 0 ,05M Dilution 1/500 Emax. 14,100 ^ 241 mu kz = 0,01047

t(min, ) A l/c

0 1.410 20 5 1,407 20.0 99 1,337 21.1 232 1,259 22.4 376 1.174 24.0 552 1,094 25.8 790 0.995 28.3 928 0.947 29.8 1419 0.811 34.8 244 T able 184 p -Toluic Acid

Temp, 20° Coac, 0,05M Dilution l/SOO \ 24lmu kz = 0.01045 E n .a x .

t(min. ) A l/c

G 1.410 20 5 1.405 20.1 99 1.309 21.5 232 1.260 22.4 376 1.170 24.1 552 1.094 25.8 790 0.997 28.3 932 0. 947 29.8 1419 0.817

Table 185 p -Toluic Acid

Temp. 20° Conc. 0 .05M Dilution 1/500 E m a x . 14,100 ^ 241 mu kg = 0.01044

t(min. ) A l/c

0 1.410 20 7 1,403 20.1 99 1.333 21.1 232 1.248 22.6 376 1.168 24.1 552 1.094 25.8 790 0.996 28.3 930 0.957 29.5 1419 0.811 34.8 245 T able 186 p-T oluic Acid

Temp, 30° Conc,, 0 .05M Dilution 1/500 ^max. 14,100 A 241mu kg = 0.0368

t(min, ) A l/c

0 1,410 20 10 1,367 20.6 48 1,282 22.0 103 1,175 24.0 160 1,082 26.1 236 0, 971 29.0 306 0.895 31.5 378 0,811 34.8 474 0,750 37.6 548 0,706 39.9

Table 187 g^-T oluic Acid

Temp, 30° Conc, 0. 05M Dilution 1/feOO Emax. 14,100 A 24lmu kg = 0,0370

t(min, ) A l/c

0 1,410 20 10 1,362 20.7 48 1,277 22,1 103 1,164 24.2 160 1,079 26,1 236 0,966 29.2 306 0, 885 31.9 378 0,815 34.6 474 0. 744 37.9 548 0,701 40.2 246 T able 188 p “Toluic Acid

Temp. 30® Conc. 0 ,05M Dilution 1/500 Emax. 14,100 \ 241 mu kz = 0.0363

t(min. ) A l/c

0 1.410 20 10 1.357 20.8 48 1.285 21.9 103 1.183 23.8 160 1.076 26.2 236 0.972 29 .0 306 0.897 31.1 378 0.815 34.6 474 0.749 37.7 547 0.713 39.6

Table 189 p “Toluic Acid

Temp. 40® Conc. 0 .05M Dilution 1/500 Emax. 14,100 ^ 241mu kz = 0.1175

t(min, ) A l/c

G 1.410 20 12 1.292 21.8 35 1.155 24.4 63 1.024 27.5 84 0.932 30.3 119 ■ 0.820 34.4 140 0.764 36.9 186 0.668 42.2 232 0.597 47.2 269 0.554 50.9 311 0.506 55.7 247 Table 190 p - T oluic Acid

Temp, 40° Conc, 0» 05M Dilution 1/500 Emax. 14,100 \ 24lmu kg = 0,119

t(iïiin. ) A l/c

0 1,410 20 12 1,327 21,3 35 1,175 24.0 63 1,037 27,2 84 0,945 29,8 119 0,823 34,3 140 0,770 36,6 186 0,682 41,4 233 0,598 47.2 270 0,562 50.2 311 0,515 54.8

Table 191 2 - T oluic Acid

Temp, 40® Conc, 0 ,05M Dilution 1/500 ^max, 14,100 \ 241 mu kg = 0,121

t(min, ) A l/c

0 1,410 20 12 1.302 21.2 35 1,154 24,4 63 1,009 28,0 84 0,945 29.8 119 0,816 34,6 140 0.716 37.1 186 0,672 41.2 233 0,596 47.3 270 0,551 51.2 311 0,509 55.4 248 T ab le 192 m-tert-Butylbenzoic Acid

Temp, 30° Conc.. 0 .05M Dilution 1/500 ^max. 9,800 A 235mu kz = 0. 0454

t{min. ) A l/c

0 0.980 20 6 0. 964 20.3 82 0.830 23.6 158 0.725 27.0 261 0. 606 32.3 427 0.498 39.4 556 0.440 44.6 666 0.393 49.9 830 0.351 55.9

Table 193 m-tert-Butylbenzoic Acid

Temp. 30° Conc. 0. 05M Dilution 1/500 Emax. 9,800 ■ A 235mu kz - 0. 468

t(min, ) A l/c +

0 0.980 20 6 0.964 20. 3 82 0. 823 23.8 158 0.722 27.2 261 0.602 32.6 427 0.488 40.2 556 0.424 46.2 666 0.388 50.5 830 0.337 58.2 249 T able 194 m-tert-Butylbenzoic Acid

Temp, 30° Conc. 0.05M Dilution 1/500 E max. 9, 800 A 235mu kg = 0.0463

t(min. ) A 1/c

0 0.980 20 6 0.960 20.4 82 0.820 23.9 158 0.723 27.1 261 0. 603 32.5 427 0,488 40.2 556 0.427 45.9 666 0.388 50.5 830 0.338 58.0

Table 195 m-tert-Butylbenzoic Acid

Temp, 40° Conc,. 0.05M Dilution \/bQQ ^max. 9,800 A 235mu kg = 0,146

t(min, ) A 1/c

0 0. 980 20 7 0.957 20.5 25 0.833 23.5 60 0.689 28.4 102 0,561 34.9 165 0.447 43.9 224 0.378 51.9 315 0.317 61.8 465 0.247 79.4 610 0.210 93.3 250 T able 196 m-tert-Butylbenzoic Acid

T emp. 40° Conc, 0 .05M Dilution 1/500 Exnax. 9.800 \ 235mu kz = 0.145

t(min, ) A l/c

0 0.980 20 6 0,957 20.5 24 0,833 23.5 59 0,689 28.4 101 0,559 35.1 164 0,451 43.5 224 0. 380 51.6 314 0,312 62.8 464 0,247 79,4 609 0,210 93,3

Table 197 m-tert-Butylbenzoic Acid

Temp, 40° Conc, 0 ,05M Dilution 1/500 Ema::. 9,800 ^ 235mu kz = 0,145

t{min. ) A l/c

0 0.980 20 5 0,958 20.5 23 0,838 23.4 58 0,694 28.2 100 0,563 34,8 163 0.452 43.4 223 0.374 52.4 313 0,310 63.2 463 0. 2 4 f 81.3 608 0.210 93.3 251 T able 198 p-te rt-Butylb enz oie Acid

Temp, 20® Conc, 0 ,05M Dilution 1/500 Emax, 15,000 \ 24lmu kg = 0,01164

t(min. ) A l/c

0 1.500 20 7 1,475 20,3 109 1,365 22,0 216 1.315 22,8 318 1,245 24,1 418 1,205 24,5 522 1,130 26,7 635 1.085 27.7 778 1,040 28,9 1252 0,865 34,7 1742 0.739 40.1

Table 199 p-tert«Butylbenzoic Acid

Temp, 20® Gone, 0 ,05M Dilution 1/feOO Emax, 15,000 \ 24lmu kz = 0.01146

t(min, ) A l/c

0 1.500 20 7 1,460 20,6 109 1.385 21.7 216 1,305 23,0 318 1,245 24.1 418 1.205 24.9 522 1.140 26,3 636 1,093 27.5 790 1.035 29.0 1252 0.867 34,6 1742 0.739 40.6 252 T able 200 p-tert-Butylbenzoic Acid

Temp. 20® Conc. 0.05M Dilution 1/500 ^max. 15,000 \ 241 mu kz = 0.01156

t(min, ) A l/c

0 1.500 20 7 1.487 20.2 109 1.382 21.7 216 1.307 23.0 318 1.237 24.2 417 1.217 24.7 522 1.144 26.2 637 1.093 27.5 796 1.031 29.1 1252 0.867 34.6 1742 0. 741 40.5

Table 201 £-tert-Butylbenzoic Acid

Temp, 30" Conc. 0.05M Dilution 1/500 Emax. 15,000 ^ 241mu kz = 0. 040

t(min. ) A l/c

0 1.500 20 13 1.475 20.3 46 1.335 22.5 83 1.265 23.7 133 1.175 25.5 194 1.070 28.0 261 0.983 30.5 324 0.883 33.8 391 0.830 36.1 501 0. 748 40.1 253 Table 202 p -te rtwButylb enzoic Acid

Temp, 30* Conc,, 0. 05M Dilution 1/500 ^max. 15,000 A 241mu kg = 0,0397

t(min, ) A l/c

0 1.500 20 13 1,445 20.8 46 1.335 22.5 83 1.252 24.0 134 1.173 25.6 194 1.071 28.0 261 0.978 30.7 324 0.885 33.9 391 0.835 35.9 501 0.746 40.2

Table 203 £-tert-Butylbenz»ic Acid

Temp, 30* Conc, 0. 05M Dilution 1/500 ^max. 15,000 A 241mu kg = 0,0397

t(min. ) A l / c

G 1.500 20 6 1.477 20.3 39 1.357 22.1 76 1,285 23.4 1 27 1,207 24.9 187 1.082 27.7 254 0.9 9 4 30.2 317 0. 912 32.9 384 0.852 35.2 503 0.744 40.3 254 Table 204 p~tert~Butylbenzoic Acid

Temp, 40® Conc. 0 ,05M Dilution 1/500 Emax. 15,000 A 241 mu kg = 0.1225

t(min, ) A l/c

0 1.500 20 6 1.486 20.2 22 1.325 2 2 .6 47 1. 152 26.0 76 1. 019 29.4 107 0.895 33.5 145 0. 783 38.3 176 0.721 41.6 229 0. 625 48.0 353 0.481 62.4

Table 205 2 -tert-Butylbenzoic Acid

Temp, 40® Conc, 0 .05M Dilution l/SOO Emax, 15,000 A 241 mu kg = 0. 1255

t(min. ) A l/c

0 1.500 20 5 1.485 20.2 21 1.335 22.5 46 1. 165 25.8 75 1.023 29.3 106 0. 888 33.8 144 0.773 38.8 175 0.713 42.1 228 0.618 48.5 352 0. 480 62.5 255 Table 206 P -t e rt~Butylbenzoic Acid

Temp, 40* Conc,. 0,05M Dilution 1/500 ^max. 15,000 A 241 mu kj, = 0, 121

t(min, ) A l / c

0 1,500 20 •4 1.487 21,2 19 1.347 22,3 44 1.163 25,8 73 1.024 29.3 104 0.909 33.0 142 0.793 37.8 173 0.734 40,9 226 0. 629 47.7 350 0.490 61.2

Table 207 m-Fluor»benzoic Acid

Temp, 30* Conc,, 0.05M Dilution 1/SOO ^max. 10,550 A 228mu kz = 0,00600

t(min, ) A l/c

0 1.055 20 20 1,049 20.1 193 1.000 21.1 313 0.962 21.9 442 0.933 22.6 651 0.882 23.9 796 0. 854 24.7 933 0. 842 25.1 1590 0. 751 28.1 1747 0.716 29.5 2040 0, 684 30.9 256 Table 208 m-Fluorobenzoic Acid

Temp* 30® Conc.. 0.05M Dilution 1/500 ^max. 10,550 A 228mu kz = 0.00590

t(min, ) A 1/c

0 1.055 20 20 1.049 20. 1 195 0. 998 21.1 313 0.966 21.8 442 0.930 22.7 651 0. 889 23.7 796 0.866 24.4 933 0.835 25.3 1590 0. 746 28.3 1747 0.711 29.7 2040 0. 685 30.8

Table 209 m-Fluorobenzoic Acid

Temp. 30® Conc. 0.05M Dilution 1/500 ^max. 10, 550 A 228mu kz = 0. 00596

t(min, ) A l/c

0 1. 055 20 22 1.041 20.3 195 0.999 21.1 317 0.965 21.9 443 0. 928 22.7 652 0. 895 23.6 800 0.867 24.3 935 0.835 25.3 1590 0.749 28.2 1747 0.716 29.5 2043 0.684 30.9 257 Table 210 m-Flu«r»b 6302oie Acid

Temp. 400 Conc. 0 ,05M Dilution 1/500 ^max. 10,550 A 228mu kz = 0.0197

t{min, ) A l / c

0 1. 055 20 7 1.050 20.1 46 1.006 21.0 94 0. 955 22.1 139 0. 928 22.7 190 0.883 23.9 252 0. 853 24.7 378 0.783 27.0 588 0. 686 30.8 719 0.650 32.5 873 0. 608 34.7

Table 211 m-Fluor«benzoic Acid

Temp, 40° C#nc. 0 ,05M Dilutien 1/500 ^max. 10,550 A 228mu kg = 0.0191

t(min, ) A l/c

0 1,055 20 7 1.055 20.0 45 1.009 21.0 93 0.986 21.4 138 0. 925 22.8 189 0.900 23.4 251 0. 849 24.9 377 0. 775 27.2 588 0.688 30.7 718 0. 641 32.9 872 0, 601 35.1 258 Table 212 m-Fluorobenzoic Acid

T emp, 40° Conc, 0 ,05M Diluti#n 1/500 E m a x . 10.550 X 228mu kz = 0,0187

t(min, ) A l/c

0 1,055 20 7 1.050 20.1 47 1.025 20. 6 93 0.979 21.6 140 0. 950 22.2 190 0.892 23.7 253 0.848 24.9 380 0. 780 27.1 589 0.687 30.7 720 0. 641 32.9 876 0.603 35.0

Table 213 m-Fluorobenzoic Acid

Temp, 50® Conc. 0 .05M Dilution 1/500 ^max, 10» 550 A 228mu kz = 0.059

t(min. ) A 1/c

0 1.055 20 4.3 1,040 20.3 10.0 1.023 20. 6 30.0 0,972 21.7 42.0 0, 940 22.5 52.3 0.918 23,0 67.2 0,883 23,9 90.0 0,834 25.3 114.3 0.791 26.7 136.0 0.755 28.0 259 T able 214 m-Fluorobenzoic Acid

Temp, 50° Conc. 0.05M Dilution 1/500 Emax. 10,550 \ 228mu kg = 0. 06l

t(min. ) A 1/c

0 1.055 20 4.0 1.036 20.4 12.3 1.019 20.7 30.0 0.961 22.0 41.8 0.934 22.6 54.2 0. 904 23.3 68.2 0. 872 24.2 79.5 0. 847 24.9 100.0 0.809 26.1 136.0 0.760 27.8

Table 215 m-Fluorobenzoic Acid

Temp. 50° Gone. 0 .05M Dilution 1/500 ^max. 10,550 A 228mu kg = 0. 0627

t(min, ) A 1/c

0 1.055 20 4.9 1.044 20.2 14.8 1.020 20.7 30.5 0.966 21.8 41.8 0.935 22.6 56.7 0.898 23.5 66.8 0.870 24.3 79.2 D. 846 24.9 111.5 0.793 26. 6 142.5 0.753 28.0 260 Table 21 6 p-Fluorobenzoic Acid

Temp. 300 Conc. 0 ,05M Dilution 1/500

E m a x . 1 1 .0 0 » \ 232mu kz = 0.0124

t(inin, ) A 1/c

0 1.100 20 5 1. 086 20.3 90 1.022 21.5 205 0. 963 22.8 300 0.913 24.1 441 ■ 0.853 25.8 ■ 612 0.789 27.9 748 0. 751 29.3 926 0. 702 31.3 1367 0. 623 35.3

Table 217 £-Fluorobenzoic Acid

Temp. 300 Conc, 0 .05M Dilution 1/500

E m a x . 1 1 .0 0 0 \ 232mu kz = 0.0127

t(min. ) A 1/c

0 1. 100 20 89 1.032 21.3 205 0. 980 22.4 301 0. 923 23.8 441 0. 852 25.8 612 0.795 27.7 748 0. 742 29.6 926 0.693 31.7 1367 0. 600 36.7 261 Table 218 p-Fluorobenzoic Acid

T emp, 30° Conc. 0.05M Dilution 1/500 E x n a x . A 232mu kz = 0.0119

t(min, ) A 1/c

0 1.100 20 5 1.092 20.1 91 1.022 21.5 214 0.965 22.8 303 0.914 24.1 445 0.854 25.8 615 0.797 27.6 750 0. 749 29.4 929 0.705 31.2 1370 0.607 36.2

Table 219 p-Fluorobenzoic Acid

Temp. 40° Conc. 0.05M Dilution 1/500 E m a x . 1 1 . 0 0 0 A 232mu kz = 0.0410

t(min. ) A l/c

0 1.100 20 6 1.076 20.4 24 1.046 21.0 69 0.953 23.1 135 0, 858 25.6 191 0.788 27.9 272 0.716 30.7 362 0. 638 34.5 435 0.595 37.0 606 0.513 42.9 742 0.460 47.8 914 0.416 52.9 262 Table 220 p-Fluorobenzoic Acid

Temp. 400 Conc, 0 ,05M Dilution 1/500 ^max» 11*000 A 232mu kz = 0.0414

t(min. ) A l/c

0 1, 100 20 7 1,063 20.7 31 1,036 21,2 74 0, 937 23.5 135 0,858 25,6 191 0,788 27,9 272 0,700 31.4 362 0, 634 34,7 435 0,591 37,2 606 0,513 42.9 742 0,462 47.6 914 0,420 52,4

Table 221 ^-Fluorobenzoic Acid

Temp, 40° Conc, 0 ,05M Dilution 1/500 ^max, 11*000 A 232mu kz = 0,0410

t(min. ) A l/c

0 1.100 20 7 1,097 20,1 35 0,019 21.6 76 0, 940 23.4 137 0. 843 26.1 210 0, 772 28,5 273 0.703 31,3 363 0. 639 34,4 435 0.589 37,4 6l6 0.504 43,7 742 0.460 47.8 918 0.421 52,3 263 Table 222 £_*Flu.orob en zo ic Acid

Temp. 50° Conc. 0 .05M Dilution l/500 ^max. 11» A 232mu kg = 0. 136

t(min. ) A l/c

G 1. 100 20 7 1. 002 22. 0 21 0. 958 23. 0 44 0. 833 26.4 62 0.760 28. 9 86 0.698 31. 5 116 0. 626 35. 1 149 G. 572 38. 5 203 0.495 44.4 256 0.441 49. 9 328 0. 397 55.4 410 0. 363 60. 6

Table 223 £^-Fluoxobenzoic Acid

Temp. 50® Gone. 0 ,05M Dilution l/SOO ^max. ^^» A 232mu kg = 0. 141

t(min. ) A l/c

0 1. 100 20 6 1.064 20.7 24 0,940 23.4 43 0. 840 26. 2 61 0.773 28.5 85 0.693 31.7 115 0. 622 35.4 148 0. 570 38.6 202 0. 490 44.9 255 0.439 50. 2 327 0. 401 54. 9 409 0.354 62. 1 264 Table 224 g_-Fluorobenzoic Acid

Temp. 50° Conc. 0. 05M Dilution l/SOO ^max. 232mu kg = 0. 135

t(min, ) A Vt

0 1. 100 20 4 1. 057 20. 9 25 0. 942 23.4 42 0. 847 26. 0 61 0.778 28. 3 86 0.701 31,4 115 0. 639 34.4 147 0. 571 38. 5 203 0.496 44.4 254 0.450 48. 9 326 0.410 53.7 411 0.365 60. 3

Table 225 m-Chlorobenzoic Acid

Temp, 30 Conc. 0. 05M Dilution l/SOO ^max. ^50 A 232mu kg = 0. 00640

t(min. ) A l/c

0 0. 885 20 8 0. 880 20. 11 87 0. 861 20.56 187 0. 830 21.33 300 0. 809 21.88 405 0.796 22. 24 568 0.749 23. 63 670 0.728 24.31 956 0. 683 25.92 1601 0. 606 29.21 265 Table 226 m-Chlorobenzoic Acid

Temp. 30® Conc. 0. 05M Dilution 1/500 Emax. 8.850 \ 232mu kg = 0. 00638

t(mln, ) A l/ c

0 0. 885 20 8 0. 883 20. 05 87 0. 863 20. 51 187 0. 832 21. 36 300 0. 804 22. 01 404 0.785 22. 55 568 0.759 23. 22 670 0.736 24. 05 956 0.679 26. 07 1601 0. 597 29.65

Table 227 m-Chlorobenzcic Acid

Temp. 30® Conc. 0. 05M Dilution l/SOO Em ax. 8, 850 A 232mu kg = 0. 006 04

t(min. ) A l/ c

0 0. 885 20 8 0. 883 20. 05 87 0. 967 20.42 187 0.836 21. 17 300 0.811 21. 82 404 0.793 22. 32 568 0.759 23. 32 670 0.735 24. 08 956 0. 688 25.73 1601 0. 612 28. 92 266 Table 228 m-Chlorobenzoic Acid

Temp. 40° Conc. 0. 05M Dilution l/SOO ^m ax. 850 A 232mu kg = 0. 0208

t(min. ) A l/c

0 0. 885 20 6 0. 879 20. 14 23 0. 856 20.68 54 0.821 21.56 130 0.774 22. 87 180 0.733 24. 15 259 0. 691 25.62 335 0.653 27. 11 417 0. 626 28. 27 585 0.559 31.66

Table 229 m-Chlorobenzoic Acid

Temp. 40° Conc. 0. 05M Dilution 1/500 ^m ax, 8» 850 A 232mu kg = 0. 00205

t(min. ) A l/ c

0 G. 885 20 6 0. 883 20. 05 23 0. 862 20. 53 54 0. 837 21. 15 130 0.779 27. 72 180 0. 746 23. 73 259 0. 704 25. 14 335 0. 667 26. 54 417 0. 634 27. 92 585 0. 562 31.49 267

Table 230 m-Chlorobenzoic Acid

Temp. 40® Conc. 0. 05M Dilution 1/500 ^m ax. 8, 850 A 232mu kz = 0. 0210

t(min. ) A l/ c

0 0. 885 20 9 0. 876 20. 21 23 0. 864 20.49 53 0. 831 21.30 129 0.780 22.69 179 0.738 23. 98 258 0. 699 25. 32 334 0. 650 27. 23 415 0. 627 28. 23 584 0. 564 31. 38

ïa b le 231 m-Chlorobenzoic Acid

Temp. 50® Conc. 0. 05M Dilution 1/500 ^max. A 232mu kg = 0. 0681

t(min. ) A l /c

0 0. 885 20 4. 2 0. 876 20. 21 11. 2 0. 871 20. 32 20. 5 0. 838 21. 12 31.7 0. 806 21.96 42.2 0. 785 22, 55 52.4 0. 754 23.47 69. 0 0.729 24. 28 84.4 0.703 25. 18 99.7 0. 671 26. 38 119. 0 0. 638 27. 74 268 Table 232 m-Chlorobenzoic Acid

Temp. 50° Conc. 0. 05M Dilution 1/500 ^max. 8, 850 \ 232mu kg = 0. 0680

t(min. ) A l / c

0 0. 885 20 3. 9 0. 877 20. 18 11. 0 0. 865 20.46 20. 0 0. 837 21. 15 31. 3 0. 807 21.93 42. 2 0. 772 22. 93 52. 0 0. 747 23.69 68. 8 0.722 24. 52 83. 9 0. 689 25. 46 100. 0 0. 669 26.46 118. 9 0. 640 27. 66

Table 233 m-Chlorobenzoic Acid

Temp. 50° Conc. 0. 05M Dilution 1/500 ^max. 850 \ 232mu kg = 0. 0656

t(min. ) A l/c

0 0. 885 20 3.7 0. 877 20. 18 10. 9 0. 868 20. 39 19. 8 0. 836 21. 17 31. 2 0. 804 22. 01 42. 2 0.773 22. 90 52. 5 0.769 23. 02 68. 5 0.731 24. 21 83.6 0.698 25. 36 99.8 0. 675 26. 22 119. 0 0.640 27. 66 269 Table 234 ^-Chlorobenzoic Acid

Temp. 20® Conc. 0, 05M Dilution 1/500 Emax. 15, 7 00 A 242mu kz = 0. 00326

t(min. ) A l/c

0 1. 570 20 17 1. 518 20.4 151 1. 478 21. 0 356 1.450 21.4 554 1.411 22. 0 798 1. 363 22. 7 1248 1. 285 24. 1 1490 1. 235 25. 1 1780 1. 180 26. 3 2177 1. 143 27. 1 2712 1. 060 29. 3

Table 235 £^-Cblorobenzoic Acid

Temp. 20® Conc. 0. 05M Dilution 1/500 ^m ax. 15, 700 A 242mu kz = 0. 00316

t(min. ) A l / c

0 1. 570 20 18 1. 529 20. 3 151 1. 500 20.7 356 1.465 21. 2 554 1.405 22. 1 798 1. 365 22. 7 1248 1. 285 24. 1 1490 1. 248 24. 8 1780 1. 188 26. 1 2177 1. 148 27. 0 2712 1. 063 29. 2 3018 1; 034 30. G 270 Table 236 £^-Chlorobenzoic Acid

Temp. 20® Conc. 0. 05M Dilution l/500 ^max. \ 242mu kg = 0. 00332

t(min. ) A l / c

G 1. 570 20 14 1. 537 20. 2 148 1.501 20. 7 360 1.458 21. 3 547 1.412 22. 0 791 1. 370 22. 6 1241 1,283 24. 2 1481 1. 242 25. 0 1773 1, 194 26. 0 2170 1. 156 26. 8 2705 1. 063 29. 2 3010 1.038 29. 9

Table 237 Chlorobenzoic Acid

Temp. 30® Conc. 0. 05M Dilution l/SOO Emax. 15.700 A 242mu kg = 0. 01248

t(min. ) A l / c _

0 1. 570 20 14 1.537 20.4 104 1.437 21. 9 248 1. 324 23. 7 345 1. 288 24.4 502 1. 178 26.7 598 1. 127 27. 9 670 1. 088 28. 9 763 1. 062 29. 6 271 Table 238 £_“Chlorobenzoic Acid

Temp. 30° Conc. 0. 05M Dilution l/500 ^max. ^5,700 A 242mu kg = 0. 0120

t(min. ) A l / c

0 1. 570 20 14 1.536 20.4 104 1.435 21. 0 250 1. 321 23.8 345 1.265 24.8 502 1. 179 26. 6 598 1. 122 28. 0 670 1. 101 28.5 763 1.063 29.5

Table 239 £_-Chlorobenzoic Acid

Temp. 30° Conc. 0. 05M Dilution 1/500 ®max. A 242mu kz=0. 0124

t(min. ) A _ i/c

0 1. 570 20 13 1. 554 20.2 105 1.455 21. 6 248 1.343 23.4 343 1. 276 24.6 500 1. 188 26.4 596 1. 142 27. 5 670 1. 101 28. 5 761 1. 072 29. 3 272 Table 240 ^-Chlorobenzoic Acid

Temp. 40® Conc. 0, 05M Dilution l/500 ^max. A 242mu k2 = 0. 041

t(min. ) A l / c

0 1. 570 20 9 1.512 20. 8 27 1.460 21. 5 75 1. 323 23. 7 117 1.243 25. 3 224 1. 050 29. 9 298 0. 950 33. 1 341 0. 912 24.4 474 0. 790 39. 8 573 0. 740 42.4

Table 241 g_~Chlorobenzoic Acid

Temp. 40® Conc. 0.05M Dilution 1/500 ^max. A 242mu kz = 0. 0432

t{min. ) A l/ c

0 1. 570 20 9 1. 532 20. 5 27 1.460 21. 5 75 1.321 23. 8 117 1.251 25. 1 224 1. 048 30. 0 298 0. 955 32. 9 341 0. 923 34. 0 474 0. 804 39. 1 573 0.739 42. 5 273 T able 242 g^-Chlorobenzoic Acid

Temp, 40® Conc, 0,0 5M Dilution 1/500 Emax, 15,700 kg = 0 ,0414 \ 242mu

t(min, ) A l/c

0 1,570 20 12 1,528 20,6 33 1,473 21,3 75 1,357 23,1 116 1,271 24,7 225 1,070 29.4 300 0,968 32.4 340 0,945 33.2 473 0.820 38,3 572 0.757 41,5

Table 243 m-Bromobenzoic Acid

Temp. 30® Conc, 0. 05M Dilution 1/500 Eo 8,500 Em 900 k g = 0,00649 A 232mu

t(min, ) A A - A(d l/c

0 0,850 0,760 20 8 0.847 0.757 20.08 73 0,838 0,748 20,32 141 0.819 0,729 20,85 250 0,788 0,698 21,78 364 0.769 0,679 22.39 433 0,759 0,669 22,72 543 0,738 0,648 23,46 675 0,716 0.626 24,28 780 0.694 0,604 25,17 1270 0,631 0,541 28.28 00 0,090 274 T able 244 m-Bromobenzoic Acid

Temp, 300 Conc, 0. 05M Dilution 1 /5 00 Eo 8,500 Eco 900 kg = 0. 00637 A232mu

t(min. ) A A - Aqj l/c

0 0.850 0.760 20 8 0. 846 0.756 20.11 73 0.837 0.747 20.35 141 0.811 0.720 21.08 250 0,781 0.691 22.00 364 0,771 0. 681 22.32 433 0.762 0.672 22.62 543 0.739 0.649 23.42 675 0.715 0.625 24.32 780 0.699 0.609 24.96 1270 0.631 0.541 28.10 00 0. 090

Table 245 m-Bromobenzoic Acid

Temp, 3Q0 Conc, 0. 05M Dilution 1/500 Eo 8,500 E(d 900 kg = 0.( 00653 A232mu

t(min, ) A A - Afl) l/c

0 0.850 0.760 20 7 0. 848 0.758 20.05 12 0.835 0.745 20. 04 140 0.814 0.724 20.99 249 0. 787 0.697 21.81 363 0.769 0.679 22.39 432 0. 752 0.662 22.96 542 0.734 0.644 23.60 674 0.714 0.624 24.36 779 0.697 0.607 25.04 1269 0.630 0.540 28.15 OD 0. 090 275 T able 246 m.-Bromoben25oic Acid

Temp. 40° Conc,, 0.05M Dilution 1/500 Eo 8,500 Eœ 900 kz = 0. 0219 A 232mu

t(min. ) A A - Aco l/c

0 0.850 0.760 20 8 0. 841 0.751 20.24 39 0. 816 0.726 20.94 93 0.763 0.673 22.59 132 0.734 0.644 23.60 199 0.704 0.614 24.76 259 0.672 0.582 26.12 336 0.637 0.547 27.79 394 0.615 0.525 28.95 516 0.581 0.491 30.96 (D 0. 090

Table 247 m-Bromobenzoic Acid

Temp. 40° Conc. G.05M Dilution 1/500 Eo 8,500 Eco 900 kg = 0.0220 A 232mu

t(min. ) A A - A(o l/c

G 0.850 0.760 20 8 0.844 0.754 20.16 38 0.814 0,724 20.99 92 0. 774 0.684 22.22 131 0. 744 0,654 23.24 198 0.716 0.626 24.28 258 0. 674 0.584 26.03 335 0.643 0.553 27.49 393 0.617 0.527 28.84 515 . 0.590 0.500 30.40 OD 0.090 276 T able 248 m-Bromobenzoic Acid

Tem p, 40® Conc. 0.05M Dilution 1/500 Eo 8,500 Eœ 900 kz = 0. 0232 232mu

t(min, ) A A - Ag) l/c

0 0.850 0.760 20 8 0.840 0.750 20.27 39 0.809 0.719 21.14 92 0.769 0.679 22.39 130 0.733 0.643 23.64 197 0.700 0.610 24.92 258 0. 668 0.578 26.30 335 0.633 0.543 27.99 393 0.610 0.520 29.23 514 0.589 0.499 30.46

(D 0.090

Table 249 m-Bromobenzoic Acid

Temp. 50° Conc. 0.05M Dilution 1/500 Eo 8,500 Eco 900 k.2 = 0. 0796 A 232mu

t(min, ) A A - Ajo l/c

0 0.850 0.760 20 4.1 0.835 0.745 20.40 10.7 0.827 0.737 20.62 21,8 0.786 0.696 21.84 32.0 0.767 0.677 22.45 4 4 .4 0.734 0.644 23.60 57.2 0.712 0. 622 24.44 71.1 0. 681 0.591 25.72 94.4 0. 643 0.553 27.49 116.0 0. 621 0.531 28.63

flO 0.090 277 Table 250 m-Bxomobenzoic Acid

Tamp, 50° Cone. 0. 05M Dilution 1/500 Eo 8,500 E(o 900 kz = 0. 0737 /\ 232mu

t(min. ) A A “ Afl) 1/c

0 0. 850 0.760 20 3.8 0.834 0.744 20.43 10. 6 0.827 0.737 20. 62 21.3 0.791 0.701 21.68 31.7 0.771 0.681 22. 32 44.6 0.733 0.643 23.64 56.8 0.710 0. 620 24.52 70.7 0. 693 0. 603 25.21 94.4 0. 655 0.565 26.90 116.0 0. 625 0.535 28.41 09 0. 090

Table 251 m-Bromobenzoic Acid

Temp. 50° Conc, 0. 05M Dilution 1/500 Eo 8,500 Eo, 900 kz = 0. 0790 / ^ 232mu

t(min. ) A A - A(d 1/c

0 0.850 0.760 20 3.8 0.837 0.747 20.35 10.6 0.831 0.741 20.51 21,1 0.794 0.704 21.59 32.0 0.760 0.670 22.69 44.8 0.734 0.644 23.60 56.4 0.712 0.622 24.44 70.6 0.684 0.594 25.59 94.6 0.651 0.561 27.09 116.0 0.624 0.534 28.46 Q) 0.090 278 T able 252 m-Methoxybenzoic Acid

Temp, 30° Conc, 0,05M Dilution 1/500 Eo 7,200 E® 10,900 kg = 0,0075 \ 221mu

t(min, ) A A - A® 1/c

0 0,720 0,370 20.0 7 0,726 0,364 20.3 135 0.755 0,335 22.1 277 0,770 0.320 23.1 440 0,793 0,297 24.9 673 0. 808 0.282 26.2 803 0.815 0.275 26.9 920 0.826 0.264 28.0 1520 0, 848 0,242 30,6 CO 1.090

Table 253 m- Methoxybenzcic Acid

Temp, 30° Conc, 0, 05M Dilution 1/500 Eo 7,200 E® 10,900 kg = 0,0072 A 221 mu

t(min, ) A A - A® 1 / c ______

0 0.720 0,370 20.0 6 0,730 0,360 20. 6 135 0,756 0,334 22,2 277 0,775 0.315 23,5 440 0,785 0.305 24.3 673 0,808 0.282 26.2 803 0.815 0.275 26.9 920 0.824 0.266 27.8 1520 0.848 0.242 30.6 00 1.090 279 Table 254 m-Methoxybenzoic Acid

Temp. 30° Conc. 0.05M Dilution 1/500 Eo 7,200 En, 10,900 kz = 0.0079 /\221m u

t(min, ) A A - A® ...... l/c

G 0.720 0.370 20. 0 6 0.726 0.364 20. 3 . 135 0.753 0.337 22.0 277 0.773 0.317 23. 3 440 0.785 0.305 24. 3 672 0.808 0.282 26.2 803 0.821 0.269 27.5 920 0.825 0.265 27.9 1520 0.850 0.240 30.8

CD 1.090

Table 255 m-Methoxybenzoic Acid

Temp. 40° Conc. 0. 05M Dilution 1/500 Eo 7,200 E® 10,900 kz = 0.0315 A 221mu

t(rtiin. ) A A - A® l / c

0 0. 720 0.370 20.0 7 0.732 0.358 20.7 50 0.759 0.331 22.4 130 0. 803 0.287 25.8 190 0.813 0.277 26.7 266 0,818 0.272 27.2 416 0.886 0.214 34.6

CD 1.090 280 Table 256 m-•Methoxybenzoic Acid

T emp, 40® Conc, 0.05M Dilution 1/500 Eo 7,200 Eo, 10,900 kz = 0. 0285 A 221mu

t(min. ) A A - Aq) l/c

0 0.720 0.370 20.0 7 0.732 0.358 20.7 50 0.766 0.324 22.8 130 0.792 0.298 24.8 190 0.813 0.277 26.7 266 0.818 1.272 27.2 417 0.868 0.222 33.3 m 1.090

Table 257 m- Methoxybenzoic Acid

Temp. 40® Conc, 0,05M Dilution 1/500 Eo 7,200 E(o 10,900 kz = 0. 0300 A 221mu

t(min, ) A A - A(n l/c

0 0.720 0.370 20.0 7 0.735 0.355 20.8 50 0.758 0.332 22.3 130 0.795 0.295 25.1 190 0.813 0.277 26.7 266 0.816 0.274 27.0 416 0.868 0.222 33.0

OD 1.090 281 T able 258 Mesitoic Acid

Temp, 0° Conc. 0.00333M Dilution 5/50 Eo 3,080 kg = 49. 7 A 234mu

t(sec, ) A 1/c

0 1.026 300 75 0.864 356 165 0.668 461 287 0.549 561 377 0.487 632 480 0,423 726 570 0.386 797 685 0.342 900 796 0.308 1000 884 0.295 1045 1020 0.264 1167 1170 0.238 1294 1305 0.220 1400 1460 0.202 1525 1603 0.186 l660 1736 0.177 1732 1891 0.1 6 6 1860 2004 0.159 1937 2215 0.153 2010 2370 0.142 2170 282 Table 259 Mesitoic Acid

Temp. 0° Conc. 0.00333M Dilution 5/50 Eo 3,080 kz = 50.1 \ 234mu

t(sec, ) A l/c

0 1.026 300 66 0. 935 330 202 0.651 463 337 0.514 598 500 0.412 745 638 0.356 864 792 0.301 1023 957 0.272 1131 1130 0. 240 1283 1312 0.218 1414 1549 0.191 1614 1775 0.171 1800 2010 0.156 1975

Table 260 Mesitoic Acid

Temp. 0° Conc. 0.00333M Dilution 5/50 Eo 3,080 kz = 49.1 \ 234mu

t(sec. ) A l/c

0 1. 026 300 102 0.785 392 263 0.579 532 417 0.461 667 567 0.394 780 689 0.348 884 867 0.304 1013 1055 0.267 1153 1200 0.234 1315 1435 0.208 1480 1684 0.187 1650 1923 0.173 1780 283 Table 26l 2, 6-Dimethylbenzoic Acid

Temp. 00 Conc. 0.0075 Dilution 10/50 Emax, 555 kz = 12. 8 272mu

t(sec, ) A 1/c

0 0.833 133 93 0.855 130 163 0.776 143 227 0.750 148 304 0.702 158 377 0.595 186 448 0.559 198 511 0,531 209 580 0.497 223 641 0.424 262 712 0.443 251 798 0.418 265 862 0.405 272 936 0. 396 280 1005 0.384 289 1119 0.369 301 1308 0.353 315 284 Table 262 2, 6«Dim.ethylbenzoic Acid

Temp, 0® Conc. 0.0075 Dilution 10/50 ^m ax, kz = 11.6 \ 272mu

t(sec, ) A l/c

0 0.833 133 95 0.782 142 170 0.740 150 237 0, 661 168 322 0.610 182 399 0.572 194 483 0.519 214 570 0.470 236 660 0.446 249 739 0.427 260 840 0.407 273 930 0.378 294 1033 0.357 311 1122 0.348 319 1211 0.338 328 1315 0.320 347 1419 0.312 356 1509 0.304 365 1598 0.298 372 285 T able 263 2, 6-Dimethylbenzoic Acid

Temp. 0° Conc, 0,0075 Dilution 10/50 Emax, 555 kz = 12,4 \ 272mu

t(sec. ) A ..... l/c

0 0.833 133 220 0.754 147 305 0. 667 166 380 0.595 187 500 0.573 193 605 0. 500 222 737 0.452 246 905 0.408 272 1108 0. 377 294 1349 0, 346 320 1596 0. 331 335 1848 0. 307 361 2135 0.293 379 2440 0.278 400 286 Table 264 m-Toluic Acid

Temp, 25° Conc,. 0,01M Dilution l/l 00 ^m ax. 9,800 A 234mu

t(miin. ) A l/c

0 0.980 100 25 0,969 101 550 0, 864 114 1380 0, 744 132 3010 0,600 163 4590 0,504 194 6270 0.446 220 9210 0, 377 260 14680 0.313 313 25660 0, 273 359

Table 265 m-Toluic Acid

Temp, 25® Conc, O.OIM Dilution l/lOO F' max. 9,800 A 234mu

t(m in, ) A l/c

0 0.980 100 25 0, 960 102 550 0,856 115 1380 0,735 134 3010 0.585 167 4590 0.498 197 6270 0.433 226 9210 0.367 267 14680 0.311 315 25660 0.264 371 287

T able 266 m-Toluic Acid

Temp. 25° Conc,. O.OIM Dilution lA 00 Em ax. 9,800 V 234mu

t(min. ) A l/c

0 0.980 100 25 0. 960 102 550 0. 868 113 1380 0.753 130 3010 0.597 164 4590 0,512 191 6270 0.451 218 9210 0. 375 261 14680 0.315 311 25660 0.274 358

Table 267 m-Toluic Acid

Temp, 35° Conc. O.OIM Dilution l/l 00 E m ax. 9,800 / \ 234mu

t(niin. ) A l/c

0 0. 980 100 20 0. 944 104 280 0.808 121 1050 0,583 168 1880 0,449 218 3000 0.382 257 4420 0, 341 288 5960 0,319 307 8810 0.306 320 17820 0.306 320 288 T able 268 m-ToIuic Acid

Temp. 35° Conc, O.OIM Dilution l/l 0 0 Exnax. % 800 A 234mu

t(min. ) A 1/c

0 0. 980 100 20 0.938 105 280 0.791 124 1050 0. 570 172 1880 0.450 218 3000 0. 373 263 4420 0.334 294 5960 0.308 318 8810 0. 316 310 17820 0. 300 327

Table 269 m -Toluic Acid

Temp, 35° Conc, O.OIM Dilution l/l 00 Emax. 9.800 ^ 234mu

t(min, ) A 1/c

0 0.980 lOO 20 0.943 104 280 0,807 122 1050 0,580 169 1880 0.455 216 3000 0,385 255 4420 0.342 287 5960 0.316 310 8810 0.310 316 17820 0.313 313 289 Table 270 m-Toluic Acid

Temp. 50° Conc,, O.OIM Dilution l/l 00 ^max. 9,800 ; y 234mu

t(min, ) A l/c

0 0.980 100 35 0.869 114 145 0.711 138 360 0.567 173 760 0.493 199 1610 0.473 207 2760 0.473 207 16110 0.480 204

Table 271 m-Toluic Acid

Temp, 50° Conc, O.OIM Dilution l/l 00 ^max. 9,800 A^ 234mu

t(min. ) A l/c

0 0. 980 100 35 0. 873 112 145 0. 704 139 360 0.561 175 760 0.492 199 1610 0.466 211 2760 0. 461 213 16110 0.468 210 290 Table 272 m-Toluic Acid

Tem p, 50° Conc,. O.OIM Dilution l/lOO ^max. 9,800 \ 234mu

t(min. ) A l/c

G 0.980 100 35 0.868 113 145 0.708 138 360 0.559 175 760 0.491 200 1610 0.473 207 2760 0.471 208 16110 0.475 206

Table 273 2 -Toluic Acid

Tem p. 25° Conc,, O.OIM Dilution 1/200 ^max. 13,800 A 241 mu

t(min, ) A l/c

0 0.690 100 20 0.684 101 650 0.622 111 1470 0.540 128 3120 0.443 156 4700 0.376 184 6370 0.338 204 9300 0.284 243 15170 0.234 295 25710 0.200 345 291 Table 274 £-Toliiic Acid

Temp. 50® Conc. O.OIM Dilution 1/200 ^max, 13,800 A 241mu

t(min, ) A l/c

0 0.690 100 10 0.684 101 78 0.552 125 295 0.372 185 385 0.337 205 610 0.287 241 1010 0. 248 278 1860 0.231 299 3000 0.230 300 4410 0.227 304 11490 0.223 309

Table 275 p-tert-Butylbenzoic Acid

Temp, 25° Conc.. O.OIM Dilution 1/200 ^max, 14,700 A 241mu

t(min. ) A l/c

0 0.735 100 20 0.729 101 650 0.646 134 1470 0.556 132 3120 0.452 163 4700 0. 381 193 6370 0.342 215 9300 0.293 251 15170 0.242 304 25710 0.207 355 292 Table 276 p^tert-Batylbenzoic Acid

Temp, 35® Conc.. 0,01M Dilution 1/200 ^max. 14,700 A 24lmu

t(min. ) A l/c

0 0,735 100 20 0,706 104 135 0,652 113 360 0.587 125 1130 0,423 174 1980 0,335 210 3090 0, 287 256 4510 0,244 301 6050 0, 229 321 8900 0, 227 324 17910 0,218 337

Table 277 2 "tert-Bntylbenzoic Acid

Temp, 50® Conc. O.OIM Dilution 1/200 ^max. 14,700 A 24lmu

t(min, ) A l/c

0 0,735 100 35 0. 671 110 135 0,569 129 360 0,431 171 760 0.373 197 I6 l0 0.357 200 2750 0,357 200 4160 0.359 199 293 Table 278 p-Fluorobenzoic Acid

Temp, 25® Conc,, O.OIM Dilution 3/500 ^m ax. 11,200 A 232mu

t{min. ) A 1/c

0 0,672 100 25 0, 624 108 550 0.605 111 1380 0,582 132 3010 0,535 126 4590 0,487 138 6270 0,456 144 9210 0,415 162 14680 0.362 185 25660 0,312 215

Table 279 p-Fluorobenzoic Acid

Temp, 35® Conc, 0, OlOfeT Dilution 3/500 11,200 E max._ /\ 232mu

t(min, ) A l/c

0 0.672 100 20 0.622 108 280 0.597 113 1050 0.522 129 1880 0.461 146 3000 0.411 164 4420 0.374 180 5960 0. 349 193 8810 0.328 205 12950 0.312 215 17820 0.306 220 24500 0,305 220 294 Table 280 p-Fluorobenzoic Acid

Temp. 50° Conc. O.OIM Dilution 3/500 ^m ax. 11,200 ^ 232mu

t(min. ) A 1/c

0 0. 672 100 35 0.615 109 155 0.554 121 370 0.485 136 770 0.445 151 1620 0.404 l66 2770 0.395 170 4190 0.398 169 295 T able 281 m-Toluic Acid (open tube)

Temp. 50- Cone. 0. OlM Dilution 1/100 A 234mu

t(min, ) A 1/c

0 0.980 100 5 0.970 101 30 0.885 111 75 0.750 131 120 0.677 145 165 0. 6l 6 159 210 0. 576 170 255 0.526 186 360 0.461 213 540 0.,392 250 675 0.363 270 1275 0.323 303 1770 0.319 307 3100 0.319 307

Table 282 m-Toluic Acid (closed tube)

Temp. 50° Cone. 0. OlM Dilution 1/100 A 234mu

t(min. ) A ...... 1/c

0 0.980 100 12 0.930 105 35 0.860 114 78 0.753 130 123 0.663 148 168 0.597 164 212 0.559 175 255 0.517 190 360 0.465 211 540 0.391 251 675 0.373 263 1275 0. 329 298 1770 0.319 307 3100 0.318 308 296 Table 283 Decomposition of Hydrazoic Acid

Temp. 40° Cone, 0, OlM Dilution 3/100 Ejjiax, (Mesitoic acid) 3,080 ki = 0. 000474/min.

t{min, ) A - A q A@-A-Ao (HNâ) 3+log(HN 3)

0 0.000 0.924 0 . 01000 1.000 15 0.006 0.918 0.00994 0.9974 50 0.016 0.908 0. 00983 0.9926 150 0.059 0.865 0. 00936 0.9713 270 0.102 0.822 0. 00890 0.9494 480 0.184 0.740 0.00801 0.9036 800 0.286 0.638 0. 00690 0.8388 OD 0.924

Table 284 Decomposition of Hydrazoic Acid

Temp. 50® Cone. 0. OlM Dilution 3/l 00 Emax. (Mesitoic acid) 3, 080 ki - 0. 00143/min.

t(min. ) A - A(Q A(g-A-A(, (HNa) 3+log(HN3)

0 0.000 0. 924 0. 01000 1,000 10 0.009 0.915 0.00990 0.996 50 0.010 0.914 0.00989 0.995 90 0. 059 0. 865 0.00936 0. 971 150 0.1 0 0 0.824 0 .00892 0.950 210 0.159 0.765 0.00830 0.919 290 0.229 0.695 0.00752 0,876 480 0.405 0.519 0.00562 0. 750 590 0.480 0.444 0.00481 0.682 800 0.597 0.327 0.00354 0.549 (D 0.924 297

Table 285 o-Toluic Acid

(H2SO4) 89.2%

(RCOOH)o 0 .005M

(HN3)o 0 .00425M

Temp. 24.2° Dilution 2/100 E^iax. 7,300 X 231.5mu

t(min. ) A (RCOOH)xlO^ (HN3)x10^ log(RCOOH) (HN)3

0 0.730 5.00 4.25 0. 070 6 0.700 4.79 4. 04 0.074 18 0.635 4.35 3. 60 0. 082 37 0.592 4. 05 3. 30 0.089 74 0.491 3.36 2. 61 0.110 104 0.446 3.05 2.30 0.123 135 0.396 2.71 1.96 0. 141 199 0.331 2.27 1.52 0.174 364 0.236 1.62 0.87 0.270 491 0.200 1.37 0. 62 0. 344 1151 0.135 0.93 0.18 0.713 00 0.110 0.75

kz = 1.51 298

Table 286 o-Toluic Acid

(H2SO4) 89.2%

(RCOOH)o 0. 005M

(HN3)o 0 .00425M

Temp, 24.2° Dilution 2/100 • E^ax. 7,300 A 231, 5mu

t(min. ) A (RCOOH)xlO^ (HN3)x10^ log(RCOOH) (HN3)

0 0.730 5.00 4.25 0.070 6 0.704 4.82 4.07 0.073 17 0.665 4.55 3.80 0,078 36 0.595 4. 08 3. 33 0.088 73 0.501 3.43 2 .6 8 0.107 104 0.449 3.08 2.33 0.121 134 0.411 2 . 82 2.07 0.134 198 0.345 . 2.36 1. 61 0.166 363 0.250 1.71 0.96 0.251 490 0.215 1.47 0.72 0.310 1150 0.149 1. 02 0.27 0.578 m 0.110 ■0.75

kg = 1. 52 299

Table 287 o-Toluic Acid

(H2SO4 ) 89.2^

(RCOOH)o 0 .005M

(HN3)o 0 .00425M

Temp. 24.2° Dilution 2/100 ^ raax. 7, 300 A 231.5mu

t(min.) A (RCOOH)xlO^ (HN3)xl0^ log(RCOOH) ______l ï ô ÿ

0 ■ 0.730 5.00 4.25 0.070 3 0.726 4.97 4.22 0.071 14 0.670 4 .5 9 3.84 0. 077 33 0. 606 4.15 3.40 0.087 70 0,518 3.55 2.80 0.103 101 0.457 3.13 2. 38 0.119 131 0. 406 2.78 2.03 0.136 195 0.345 2.36 1.61 0. 166 360 0.251 1.72 0 .9 7 0,249 487 0.214 1.47 0.72 0.310 1147 0.147 1.01 0.26 0,589 CD 0. 110 0.75 •

k z = 1.51 300

T able 288 o-Toluic Acid

(H2SO4)

(RCOOH)o 0. 005M

(HN3)o 0 ,00425M

Temp, 24,2° Dilution 2/100 Emax, 7,300 A 231,5mu

t(min, ) A (RCOOH)xlO^ (HN3)x103 log(RCOQH) ______(HN3)

0 0.730 5,00 4,25 0, 070 19 0. 648 4,44 3,69 0. 080 85 0. 537 3,68 2,93 0,099 150 0.437 2,99 2,24 0,125 219 0. 378 2,59 1,84 0.149 316 0. 314 2,15 1,40 0,186 404 0.278 1,90 1, 15 0.218 494 0.252 1,73 0,98 0,247 560 0.238 1.63 0,89 0,263 1070 0.172 1.18 0,43 0.438 1560 0.139 0,95 0.20 0,677 00 0.110 0.75

kg = 1,127 301

Table 289 o^-Toluic Acid

(H2SO4) 87.5fc

(RCOOH)o 0. 005M

(HN3)o 0 .00425M

Temp. 24.2° Dilution 2/100 7,300 /K 231. 5mu

t(min. ) A (RCOOH)xlO^ (HN3)x10^ log(RCOOH) (HN3)

0 0 0.730 5.00 4.25 0.070 14 0.671 4. 60 3.85 0. 077 80 0.540 3.70 2.95 0.098 146 0.445 3.05 2. 30 0. 123 215 0. 381 2.61 1.86 0. 147 312 0. 318 2. 18 1.43 0. 183 400 0.277 1.90 1.15 0.218 490 0.253 1.73 0.98 0.247 556 0.237 1. 62 0. 87 0.270 1065 0.171 G. 17 0.42 0.445 1556 0.139 0.95 0.20 0. 677 m 0. 110 0.75

kz = 1.105 302

Table 290 o-Toluic Acid

{H2SO4) 82.8%

(RCOOH)o 0.005M

(HNs)o 0 .00425M

Temp. 24,2® Dilution 2/100 7,300 A 231. 5mu

t(min. ) A (RCOOH)x103 (HN3)x10^ log(RCOOH) (HN3)

0 0.730 5.00 4.25 0.070 9 0.706 4. 84 4.0 9 0.073 56 0.633 4. 34 3. 59 0.082 125 0.532 3.64 2.89 0.100 202 0.456 3.12 2.37 0.119 272 0.407 2.79 2.04 0.136 326 0.383 2.62 1. 87 0.146 381 0.353 2.42 1.67 0.161 523 0.300 2.06 1. 31 0.197 674 0.263 1.80 1.05 0.234 790 0.244 1.67 0.92 0.259 1302 0.186 1.27 0. 52 0. 388 1558 0.169 1.16 0.41 0.452 1824 0.165 1.13 0. 36 0.4 9 7 2190 0.147 1.01 0.26 0.589 3073 0.134 0 .9 2 0.17 0.733 CD 0.110 0.75

kz = 0.749 303

Table 291 o-Toluic Acid

(H2SO4) 82.8

(RCOOH)o 0 .005M

(HN3)o 0. 00425M

Temp, 24,2° Dilution 2/100 E^^^ax. 7,300 A 231, 5mu

t(min, ) A (R COOH)xl 0^ (HN3)x1 0^ log(RCOOH) (HN3)

0 0.730 5. 00 4.25 0. 070 8 0.710 4.86 4. 11 0. 073 55 0.632 4.33 3.58 0. 082 124 0,543 3.72 2. 97 0.098 201 0.461 3.16 2.41 0.118 271 0.411 2.82 2. 07 0.134 325 0.381 2.61 1,86 0.147 380 0.356 2.44 1.69 0.160 522 0,307 2.1 0 1. 35 0.192 673 0.266 1.82 1. 07 0.231 789 0.245 1.68 0.93 0.257 1301 0.187 1,28 0.53 0. 383 1557 0.175 1,20 0. 45 0.426 1823 0.161 1.10 0. 35 0.497 2189 0.150 1.03 0, 28 0. 566 3072 0,135 0.93 0. 18 0.713 (D 0.110 0.75

kü = 0.732 304

Table 292 o-Toluic Acid

(H2SO4) 82.89G

(RCOOH)o 0. 005M

(HN3)o 0 .00425M

Temp, 24.2° Dilution 2/100 E^ax. 7,300 A 231, 5mu

t(min. ) A (RCOOH)x103 (HNsjxlOS log(RCOOH) (HN3)

0 0.730 5.00 4,25 0,070 7 0.707 4. 84 4 ,0 9 0,077 54 0.628 4.30 3.55 0,083 123 0.539 3,69 2. 94 0. 099 200 0.457 3.13 2,38 0. 119 270 0,409 2.80 2,05 0.135 324 0.379 2. 60 1.85 0.148 379 0,353 2.42 1.67 0,161 521 0,304 2,08 1.33 0,194 672 0,267 1,83 1.08 0,229 788 0,246 1,69 0 ,9 4 0,255 1300 0.188 1.29 0,54 0,378 1556 0,172 1,18 0,43 0,438 1822 0,163 1.12 0,37 0,481 2189 0.151 1,03 0,28 0.566 3071 0,136 0 ,9 3 0,18 0,713 CD 0,110 0,75

kg " 0.740 305

Table 293 e-Toluic Acid

(H2SO4) 80 . 1 %

(RCOOH)o 0. 005M

(HNs)o 0. 00425M

Temp. 24,2° Dilution 2/100 Ernax. 7,300 A 231. 5mu

t(inin, ) A (RCOOH)xl 0^ (HNsjxlQ: log(RCOOH) (HN3)

G 0.730 5.00 4.25 0. 070 12 0.695 4.76 4.01 0.075 76 0.641 4 .3 9 3.64 0.081 141 0.585 4.01 3.26 0 .0 9 0 210 0.543 3.72 2.97 0.098 307 0.483 3.31 2.56 0. 112 395 0.446 3.06 2.31 0.122 485 0.415 2.84 2.09 0.133 551 0.397 2.72 1.97 0.140 1060 0.298 2.04 1.29 0.199 1551 0.242 1.66 0.91 0.261 2492 0.190 1.30 0.55 0. 374 3986 0.155 1.06 0.31 0.534 5810 0.134 0.92 0.17 0.738 m 0.110 0.75

kz = 0. 381 306

Table 294 o-Toluic Acid

(H2SO4) 80.1 %

(RCOOH)o G. 005M

(HN3)o 0 .00425M

Temp. 24.2° Dilution 2/lGG 7,300 \ 231. 5mu

t(min. ) A (RCOOH)xlO^ (HN3)x10^ log(RCOOH)

^ • (HN3)

G 0.730 5.00 4.25 0. 070 10 0. 698 4.78 4. 03 0.074 74 0. 640 4. 38 3. 63 0. 082 140 0.589 4.03 3.28 0.090 208 0.548 3.75 3.00 0.097 305 0.4 9 5 3. 39 2. 64 0.109 393 0.457 3. 13 2. 38 0.119 483 0.4 2 9 2 .9 4 2. 19 0. 128 549 0.408 2. 79 2.04 0.136 1060 0. 305 2.09 1.34 0.193 1549 0.253 1.73 0. 98 0.247 2490 0.199 1. 36 0. 61 0. 348 3984 0.161 1.10 0. 35 0.497 5807 0. 142 0. 97 0.22 0. 644 (D 0. 110 0.75

kg = G. 364 307

T able 295 o-Toluic Acid

(H2SO4) 80.1%

(RCOOH)o 0 ,005M

(HN3)o 0 .00425M

Temp. 24.2° Dilution 2/IOO E^^ax. ?,300 X 231. 5mu

t(min. ) A (RCOOH)xlO^ (HN3)x103 log(RCOOH) (HN3)

O 0.730 5.00 4.25 0. 070 7 0.710 4.86 4.11 0.073 71 0. 653 4.47 3.72 0. 080 137 0.601 4.12 3. 37 0.087 205 0.551 3.77 3.02 0.096 302 0.498 3.41 2 .6 6 0.108 390 0.463 3.17 2.42 0.117 480 0.433 2.97 2.22 0.126 546 0.411 2.82 2.07 0. 134 1057 0.310 2.12 1.37 0.189 1547 0.260 1.78 1.03 0.238 2488 0.205 1.40 0. 65 0. 333 3982 0.1 6 7 1. 14 0.39 0.466 5805 0.147 . 1.01 0. 26 0. 589 OD 0.110 0.75

kg = 0. 356 308

Table 296 o-Toluic Acid

(H2SO4) 77. 1 %

(RCOOH)o 0. 005M

(HN3)o 0 .00425M

Temp, 24.2 Dilution 2/lOG 7, 300 )\ 231.5mu

t(min. ) A (RCOOH)x103 (HN3)x 10^ log(RCOOH) (HN3)

0 0.730 5.00 4. 25 0. 070 11 0.739 5.06 4. 31 0. 070 968 0.524 3.59 2. 84 0. 102 1885 0.421 2.88 2.13 0. 131 2887 0.340 2.33 1.58 0.169 3676 0.304 2,08 1. 33 0.194 4287 0.283 1.94 1.19 0. 212 5027 0.273 1.87 1. 12 0.223 6248 0.243 1. 66 0. 91 0.261 7371 0.229 1.57 0. 82 0. 282 8616 0.213 1.46 0.71 0. 313 10245 0.197 1.35 0. 60 0. 352 12016 0.189 1.30 0.55 0. 374 13416 0.182 1.25 0. 50 0. 398 GD 0.110 0. 75

kz = 0.1038 309

Table 297 o-Toluic Acid

(H2SO4) 77.1 fo

(RCOOH)o 0 .005M

(HN3)o 0 ,00425M

Temp, 24.2* Dilution 2/100 7,300 \ 231.5rnu

t(rain, ) A (RCOOH)xlO^ (HN3)x 103 log(RCOOH) (HN3)

0 0.730 5.00 4.25 0. 070 9 0.742 5.08 4. 33 0.069 966 0.518 3.55 2. 80 0.103 1883 0.429 2 .9 4 2. 19 0.128 2885 0.348 2. 38 1. 63 0.164 3674 0.304 2.08 1.33 0.1 9 4 4285 0.285 1.95 1.20 0.211 5025 0.268 1.84 1.09 0.227 6246 0.256 1.75 1.00 0.243 7370 0.228 1.56 0.81 0.285 8614 0.214 1.47 0.72 0.310 10243 0.201 1.38 0.63 0.340 12014 ■ 0.194 1.33 0.58 0.360

(D 0.110 0.75

kz = 0.1019 310

T able 298 o-Toluic Acid

(H2SO4 ) 77.1%

(RCOOH)o 0. 005M

(HN3 )o 0.00425M

Temp. 24.2° Dilution 2/100 ^rnax, "7» 300 \ 2 3 1 .5mu

t(m in. ) A {RCOOH)xl03 (HN 3)x 1 0 ^ log(RCOOH) (HN3)

0 0.730 5.00 4.25 0. 070 9 0.744 5.10 4. 35 0.069 966 0.515 3.53 2.78 0.104 1883 0.417 2 .8 6 2.11 0. 132 2885 0. 348 2.38 1. 63 0.164 3674 0.304 2. 08 1. 33 0.194 4285 0,288 1.97 1. 22 0.208 5025 0.265 1.82 1.07 0.231 6246 0.250 1.71 0.76 0.251 7370 0.240 1.64 0.89 0. 266 8614 0.215 1.47 0.72 0.310 10243 0.204 1.40 0. 65 0.333 12014 0.209 1.43 0.68 0.323 13414 0.190 1.30 0.55 0.374 0.110 0.75

kg = 0.1032 311

T able 299 o-Toluic Acid

(H2SO4) 74. 4 fc

(RCOOH)o 0. 005M

(HN))o 0 .00425M

Temp. 24.2° •Dilution 2/100 E^ax. 7,300 231.5mu

t(min. ) A (RCOOH)x103' (HN3)x103 log(RCQOH) ______(HN3)

0 0.730 5.00 4.25 0.070 8 0.727 4. 98 4.23 0.071 402 0.686 4.70 3.95 0.076 946 0.647 4. 43 3. 68 0.081 1425 0.610 4.18 3.43 0. 086 1830 0.581 3. 98 3.23 0.091 2845 0.533 3.65 2. 90 0.100 4680 0.452 3. 10 2. 35 0.120 5940 0.428 2 .9 3 2 . 18 0.128 7600 0.377 2.58 1. 83 0. 149 9590 0.343 2. 35 1.60 0.167 13500 0. 326 2.23 1.48 0.178 17560 0.299 2.05 1. 30 0.198 21130 0.273 1.87 1. 12 0.223 (D 0.110 0.75

kz = 0.0313 312

Table 300 o-Toluic Acid

(H2SO4) 74.4%

(RCOOH)o 0 .005M

(HN3)o 0 .00425M

Temp. 24.2' Dilution 2/110 7, 300 \ 231.5mu

t(min. ) A (RCOOH)xlO^ (HN3)x 10^ log(RCOOH) ~ W h )

0 0.730 5.00 4.25 0.070 8 0.744 5. 10 5.35 0.069 402 0.692 4. 74 3.99 0, 075 946 0. 649 4. 45 3.70 0. 080 1425 0.612 4. 19 3.44 0. 086 1830 0.580 3.97 3.22 0.091 2845 0.540 3.70 2.95 0,098 4680 0.453 3. 10 2.35 0,120 5940 0.422 2.89 2.14 0. 130 7600 0.385 2.64 1.89 0. 145 9590 0.360 2.47 1.72 0.157 13500 0.329 2.25 1.50 0. 1T6 17560 0.284 1.95 1.20 0.211 m 0.110 0. 75

kg = 0. 031 6 313

Table 301 o-Toluic Acid

(H2SO4) 74. 49 ;

(RCOOH) 0 .005M

(HN3)o 0 .00425M

Temp, 24,2 Dilution 2/lGO Emax, 7,300 \ 231,5mu

t(min, ) A (RCOOH)x103 (HN3)x1Q3 log(RCOOH) ______(HN3)

0 0.730 5,00 4,25 0. 070 8 0.730 5.00 4. 25 0.070 402 0,699 4.79 04 0,074 946 0, 656 4.49 3.74 0,079 1425 0,629 4.31 3.56 0.083 1830 0,588 4. 03 3.28 0,090 2845 0.542 3.71 2.96 0.098 4680 0.465 3.19 2.44 0.116 5940 0,427 2.92 2.17 0.129 (D 0,110 0,75

kg = 0. 0313 314 Table 302 o^-Toluic Acid {H2SO4) 73.8%

Temp. 24.2° Cone. 0.002M Dilution 5/100 Emax. 7* 300 kg = 0,0264 A 231.5mu

t(hrs. ) A l/c

0 0.730 500 0.3 0.728 501 23 0.677 539 46.3 0. 637 574 70 0.595 613 94 0. 562 650 131 0.522 699 160 0.492 743 208 0.459 793 257 0.428 852 373 0.376 974 430 0.352 1037

Table 303 o-Toluic Acid (H2SO4) 73.8%

Temp. 24.2° Conc. 0 .002M Dilution 5/l 0 0 Emax. 7,300 kz = 0.0259 ^ 231. 5mu

t(hrs. ) A l/c

0 0.730 500 0. 3 0. 726 503 23 0. 678 538 46. 3 0. 632 578 70 0.601 607 94 0. 562 650 131 0.523 697 160 0.496 736 208 0.460 793 257 0.426 857 314 0. 397 920 373 0. 378 967 430 0. 354 1033 315 Table 304 o-Toluic Acid (H2SO4) 73.892

Temp, 24.20 Conc. 0 .002M Dilution 5/100 ^max. 7, 300 kz = 0.0257 \ 231.5mu

t(h.rSo ) A 1/c

0 0.730 500 0.3 0. 720 507 23 0. 678 538 46. 3 0. 632 578 70 0. 602 607 94 0.563 648 131 0.516 707 160 0.490 745 208 0.454 804 257 0. 423 861 314 0. 393 929 373 0. 369 990 430 0. 346 1054

Table 305 _o-Toluic Acid (H2SO4) 71,6%

Temp. 24.2® Conc. 0.002M Dilution 5/100 ^max. kz = 0.00883 \ 231. 5mu

t(brs. ) A l/c

0 0.730 500 0.3 0.723 505 %3 0.711 514 46.3 0.699 522 70 0.685 533 94 0. 659 553 131 0.642 568 160 0. 623 585 208 0.597 612 257 0.580 629 314 0.555 658 373 0.535 682 430 0.519 703 316 Table 306 o-Toluic Acid (H2SO4) 71.6#

Temp. 24.2® Conc. 0. 002M Dilution 5/100 Exnax. 7» 300 kg = 0. 00867 \ 231.5mu

t(hrs. ) A 1/c

0 0.730 500 0.3 0.718 508 23 0.709 515 46.3 0.692 527 70 0. 668 546 94 0.659 554 131 0.637 574 160 0.619 589 208 0.598 610 257 0.575 635 314 0.553 660 373 0.532 687 430 0.517 707

Table 307 o-Toluic Acid (H2SO4) 71.6#

T emp, 24, 2° Conc. 0 .002M Dilution 5/100 ^max, 7,300 kg = 0.00875 A 231.5mu

t(h.rs, ) A 1/c

0 0.730 500 0.3 0.719 508 23 0.707 516 46.3 0. 689 530 70 0.669 546 94 0. 654 558 131 0. 645 566 160 0.622 588 208 0.601 608 257 0.575 635 314 0.555 658 373 0.535 683 430 0.520 703 317 Table 308 o-Toluic Acid (HgSOj 97.0%

Temp. 24.2* Conc. 0,005M Dilution 2/100 E„,ax. 7,300 kg = 2 ,96 \ 231,5mu

t(min. ) A 1/c

0 0,730 500 14 0,715 510 26 0.633 577 48 0,517 706 72 0.442 826 * 111 0,359 1017 157 0.300 1216 208 0,263 1388 345 0,223 1637 530 0.193 1819

Table 309 o-Toluic Acid {H2SO4) 97 . 0 %

Temp, 24,2° Conc, 0,005M Dilution 2/100 ^max, 7,300 kg = 2.80 A 231,5mu

t(min, ) A 1/c

0 0,730 500 13 0,707 516 25 0.634 576 47 0,523 698 71 0,452 808 110 0,375 973 156 0.319 1144 207 0.281 1299 344 0,224 1629 530 0,194 1881 318 Table 310 o-Toluic Acid (HgSOj 97.0%

Temp, 24.2° Conc. 0 ,005M Dilution 2/100 Emax. 7,300 kg = 2. 96 A 231.5mu

t(min, ) A l/c

0 0.730 500 11 0.717 509 23 0.612 596 45 0.514 710 69 0.433 824 108 0.366 997 154 0. 327 1116 205 0.273 1337 342 0.223 1637 528 0.198 1843 AUTOBIOGRAPHY

I, Melville Ernest Douglas Hillman, was born in Winnipeg,

Manitoba, Canada;on August 3, 1926, My primary school

education was obtained in the public schools of Saskatoon,

Saskatchewan,and my secondary school education was obtained

in the high schools of Toronto, Ontario,and Vancouver, British

Columbia, From 1945 to 1948 I was employed as a horticulturist

with the Canadian Pacific Railway Company,

I obtained my undergraduate training at the University of

British Columbia (1948-1952) and received a Bachelor of Arts, with honors in Chemistry in 1952, I was appointed a graduate assistant in the Department of Chemistry during the academic year

1952-1953, In 1953-1954 I held the Canadian Industries Ltd, Fellow­ ship, In 1954 I received the degree Master of Science from the

University of British Columbia,

In 1954 I came to The Ohio State University where I held the position of Graduate Teaching Assistant from 1954-1956, I was awarded the Lubrizol Company Fellowship in 1956 and the Socony-

Mobile Fellowship in 1957, During part of 1958 the Department of

Chemistry of The Ohio State University supported me on department funds to enable me to complete the requirements for the Ph. D, degree,

319