A GENERAL C 0 N 0 E P T I 0 N 0 F AC I D S AND B ASE S By Dale H. Puffett Submitted to the Department of Chemistry and to the Faculty of the Graduate School of the Uni vei-•si ty of Kansas in partial fulfillment of the requirements :for the Master's degree. Approved by: Department of Chemisbry May 25, 1923 At this place the writer wishes to record his appreciation of the manner in which Dr. H, P. Cady has directed this. work and in which Dr. H. :M. Elsey has aided in the preparation of apparatus; and to acknowledge his indebtedness to both. Dr. Cady and Dr. Elsey for many helpful ideas and suggestions. C 0 N T E N T S introduction 1 Statement o:r Conception· - 2 Methyl Annnonium Sul:fi te 4 Caesium Sulfite I 7 Pollucite 9 Caesium Sulf'ite II 12 Caesium Sulfite III - 14 Silver Sulfite 17 Potassium Sulfite 18 Selenium Oxybromide 22 Phosphort.1~ Oxychloride 23 t" Sununary 27 Bibliography 28 A GENER.AL CONCEPTION OF ACIDS AND .BASES Acids a~d bases are connnonly defined With· aqueous . solutions alone in view·. Thus· a tvidely~· used textbook on· physical chemistry states that "any electrolyte which gives hydrogen-ion (H..,.) as· one' o:r· the· direct products or· its ionization is called an acid1";;' and· that "- any electro- lyte which gives hydroxyl-ion as ohe oT the direct proa- ucts o:r its ionization is called a base": 'Yet more than 2 . .. twen~y years ago Franklin . observed that certain··substances when dissolved in liquid ammonia possessed properties which were strictly analogous to those·,· mani·:fested by acids or bases in aqueous so"intions, and that ·reactions took place between members o:r these two classes. of substances' which were essentially the same as neutralization reactions be- . tween acids and bases in water solutions. Thus sodimn and potassium amides behave as bases when in solution in liquid.· ammonia, and acetamide and benzamide act as acids. The re- actions bettveen these substance·s may be represented by·'.the equations I ~'.. + - +" Na + NH + CH CONH + H = CH CONHNa + NH 2 3 3 3 K++NH; +C H CONH-+ H + 'CeoH CONHK + NH 6 5 = 5 3 1 E.W. Washburn; An Introduction to the P~nciples o:r Physical Chemistry; Second Edition. See pp. 361-2. ~ ' . .. 2 . ~ Franklin and Kraus; Electrical Conductivity of Liquid .Annnonia Solutions; .American Chemical Journal, 23 , 277-313. ~ + ~~- This ion is no doubt sol vated and representable by (H•NH3 ). These reactions are clearly analogous· to the :rollmving ones in aqueous solutions + - . - + Na +OH +CH COO +H = CH COONa + H 0 3 3 2 + - . - + K + OH + c H COO + H C H COOK + H 0 6 5 = 6 5 2 General definitions which not only cover each of these cases equally well but also are entirely :rree :rrom specifications as to the com1)osi tion · o:r electrolyte or solvent were set :rorth in a paper.read at the Birmingham meeting of the .American Chemical Society in the spring of 1922; which contained the follO\ving statment: " An acid :ror any system involving an.ionizing solvent is.a substance which :rorms by its direct ionization a cation identical with the positive ion of the solvent, and a base is one which furnishes an anion which is the same as the negative ion of the solvent.· If,then, there were brought together in such a solvent two substances, one giving the same cation as that of the solvent (the acid), and the other yielding the same anion as the solvent (the base), neutral- ization would take place with the formation o:r more of the solvent and a solution o:f a nelv s.al t." necause of the great similarity between' water ·and ammonia (their positive ions are identical and their neg- ative ions have the element hydrogen in.common), the study of these two systems cannot· conclusively substantiate such ~" H.P.Cady and H.M.Elsey, A General Conception o:r Acids, Bases, and Salts. a general conception of acids and.bases. For this ·purpose the study o:r solution~in solvents which contain no hydrogen is obviously the most satisractory. o:r all solvents containing no hydrogen, liquid sulfur 1 2 3 dioxide appeared to be the most promising as a dissociative ' ' medium in addition to being readily available and fairly convenient of manipulation. Consequently it was selected as the first solvent to be used in an efrort to test out exper- imentally the above conception of acids and bases. Ionization of sul:rur dioxide may be considered to take . 1 place in one or more o:r the following ways: 802 = s+++;-+ 2 0-- S++++ i- 2 so . 380 = "3 2 802 = 80-r-t- -t- o- - 2802 = sc(-t- +so;- The last manner of ionization seems the most probable, at least as far as the primary dissociation is concerned; but according ~o either of the last two views thionyl chloride ( assuming the dissociation SOC1 = SO++ -r 201- ) should act as 2 an acid when dissolved in sulf'ur dioxide, while the sulfites ionization M so = 2M~ so3- in the latter case (asswning the 2 3 + -- M 2M ..,.. O so in the former) and the dissociation 2 so 3 = + 2 '! • L Walden and Centnerszwer; Flussiges Svhwe:reldioxyd als Lcfaungsmi ttel; Zei tschrift f. phys. Chemie; 39 , 513-596. 2. Walden; Ueber ein neues, anorganisches, ionisirendes h Losungsmittel; Berichte; 32 , 2862-2871. 3. Walden; Uber abnorme Elektrolyte; Zeit. f. phys. Chemie; 43, 385-464. ·should act as bases. While thionyl chloride was used as the hypothetical acid throughout the lVork on sulfur dioxide solu- 1 tions, a nmnber of sulfites were utilized in the basic role. The first' of the latt.er was methyl anunonium sul:fi te, (CI-I NH } so • 3 2 2 3 This was prepared as follows: A measured volume o:f a strong aqueous sblution of methyl amine was saturated with so 2 gas and an equal volume of the untreated amine solution was then added; the liquid tvas evaporated to dryness over an () electric lamp at a temperature of about 40 c. .•t. A two-legged Pyrex tube o:r the type used by Franklin .. in his work on chemical reactions in liquid ammonia was prepared and provided with a stopcoclr. About two gran1s of dry methylannnonium sulfite· were introduced into one leg and the end was.sealed off. :About one cubic centimeter o:f thionyl chloride was then poured into the other leg, and the end o:r this was"likeWise sealed o:r:r. A slow stream of' so gas was allowed to pass through the apparatus duting 2 the introduction of materials and sealing. This was done not only to protect the materials from atmospheric moisture but also to sweep out the air so that sulfur dioxide could later be readily distilled into the tube. This addition of so by distil~ation 2 was accomplished simply by placing the ~· leg o:f the tube containing the sul:fite in a freezing mixture of ice and salt and connecting the tube with a cylinder of connnercial sulfur dioxide. When about :fi:fteen cc. o:f so 2 Franklin and Stafford; Reactions between Acid and Basic Amides in Liquid Anni1onia; .Amer. Chem. Jour. ; 28 , 83-107. had distilled in the stopcock was turned and wired in place, and the comiection with the cylinder lvas brolren. The tube was removed from th~ freezing mixture, the 80 was warmed 2 to approximately room temperature, and the liquid above the sulfite was poured over into the leg containing thionyl cltloride. The sulf'ur dioxide tvas then distilled baclr into the sulfite compartment by placing that leg in the freezing mixture and the other in tepid water. The solvent was next warmed _as before and poured off' from the sulf'i te baclc into the thionyl chloride chamber. This process of' alter- nate pouring and'distillation of' the 802 was continued until all ·the sulf'i te had dissolved and been poured o-eer into the thionyl chloride. A white solid separated out in the SOCl compartment, and this was purified by pouring 2 . off the supernatant liquid into the other leg. The so 2 was distilled back.as described. above, and this washing with the solvent was repeated about six times. With all the \vashi~ga collected in the original sulfite leg, the stopcock was turned and the sulfur dioxide allmved to evaporate. To make the removal of absorbed solvent as complete as possible, the tube was kept evacuated with a filter pump for at least fifteen hours. The leg con- taining the lVhite solid was cut off from the rest of' the apparatus, and the product was poured out into a weighing bottle and subjected to analysis. The material was readily soluble in water. The absence of chlorides was shown by the :failure of the aque- ous···solution, made slightly acid with nitric acid, to give a precipitate upon the addition of a solution of silver nitrate. A determination of nitrogen by the Kjel- dahl method gave tbe following results: Trial I Weight of bottle & sample 10.9158 grams fl II " 10.7307 ". If ft ff 0.1851 II Volume of,0.5 normal HCl placed in absorption :flask: 45.00 cc. Volume of D.5 normal·NaOH required :for neutrali- zation: 41.40 cc. 0.01401 (45.00 ~ 41.40) 0.0252 gm. of nitrogen 2 = (as ammonia) collected. 0 0252 o.1851• 100 -- 13.61 %o :f ni t rogen i n sample.