".lectrodeposition of
Aluminum from Organic Solutions"
by
M.C. Sze
Submitted in Partial Fulfillment of The
Requirement for The Degree of
Bachelor of Science
in
The Departmenr of Chemical Engineering
from
Massachusetts Instituue of Technology
1939
Signature redacted Signature of Author , - 61
Signature of Professor in Charge
Signature of Head of Department I ,.I.T. Dorm., Cambridge, Mass., May 15, 1939.
Professor Walter G, Whitman, Head of the Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Mass.
Dear Sir:
I am enclosing herewith my thesis on
"Electrodepostion of Aluminum from Organic Solutions", submitted in partial fulfillment of the requirement for the degree of Bachelor of Science. From my laboratory results, I have Zbached the conclusion that aluminum can be successfully electrodeposited from non-aqueous solutions to give a bright and adherent film.
Yours respectifully, Signature redacted (Morg n C. Sze) Acknowledgment
The author wishes to express his appreciation to his supervisor, Dr. H. H. Uhlig, for his assistance and advice in the preparation of this thesis. ABLr Of CONuA\N.LS
I. SUMMARY Page 1 II. INTRODUCTION 2
III. LITERATURE SURVEY 3
IV. PROCEDURE 5
V. RESULTS AND DISCUSSION 7 VI. CONCLUSIONS 20
VII. RECOMMENDATIONS 21
VIII. APPENDIX A - DETAILS OF THE PREPARATION AND DEHYDRATION
O0 SOME OF THE COMPOUNDS USED 22
IX. APPENDIX B - ORIGINAL DATA 25
X. APPENDIX C - DESCRIPTION OF THE
ELECTROLYTIC CELL USED 29
XI. APPENDIX D - BIBLIOGRAPHY 31 - 1 -
I* SUMMARY
The results of this investigation indicate that aluminum can be electrolytically deposited to give an adherent and bright plate. The electrolytes most satisfactory for this purpose are found to be the following: (1) A solution containing the reaction products formed when aluminum bromide and aluminum chloride are dissolved in ethyl bromide and benzene (2) and (2) A solution containing the reaction products of aluminum chloride and ethyl bromide in chlorobenzene.
It has been found that lyophilic colloids for benzene like rubber, milled or unmilled, are capable of giving a pronouneed brightening effect to the deposit.
Upon buffing, a beautiful, silvery luster is easily obtained. Low current density is also a necessary condition to obtain a satisfactory deposit.
Various other solutions have been studied, but they are all unsatisfactory,for either aluminum cannot be deposited, or the cathode current efficiency is extremely low. II. INTRODUCTION
The purpose of this thesis was to try to electro- plate metallic aluminum from non-aqueous solutions to give an adherent and bright film. It has been long recognized that it is impossible to electro- deposit aluminum from aqueous solutions, simply because of side reactions at the electrodes. Never-
theless, it has been shown that aluminum can be
obtained electrolytically from organic solutions in
the absence of water, although it is not known that any entirely satisfactory deposit has been previously
obtained. Aluminum plating is of considerable commercial
interest-. beside possessing an ornamental appearance, aluminum can also protect the iron or steel on which it
is plated against corrosion. It is resistant to
concentrated nitric acid free from chlorides.
Aluminum plated steel has the advantage of possessing a surface of low emissivity together with high mechanical
strength. This is often very desirable, such as in
refrigerator car surfaces, etc. III. LITERATURE SURVEY
Evidence of aluminum being electrolytically deposited was first noticed by elotnikoff ~ 1 )during an electrolysis of aluminum bromide in ethyl bromide in 1902. This work was confirmed by Patten(13) who determined the single potential of aluminum in
such a solution. These were probably the earliest work done in this field.
Later in 1916 Lalbin had found that aluminum
could be deposited from a 10% solution of AlCl 3 in acetonitrile. Potassium fluoride was added to in-
crease the conductance. Keyes, Swann, Klabinde, and Schicktanz(6) electrolyzed a solution of aluminum
diethyl iodide and aluminum ethyl di-iodide and
obtained aluminum. Quintin Marino(l 4 ) used a solution of aluminum oxalate and tartrate in liquid ammonia at low temperatures. In 1933, Keyes, Phipps, and Klabinde had found that aluminum can also be
deposited from a solution of AlBr3 in (Et)4 NBr. The latest electrolyte for aluminum deposition
was that found by Blue and Mathers(1)(2). They
used a solution containing the reaction products
of aluminum bromide, aluminum chloride, and ethyl bromide in benzene and xylene. According to the investigators, this solution had a surprisingly high conductance. besides, it also gave high current efficiencies. However, satisfactory aluminum deposits had never been obtained. They were always dark and often not very adherent. IV. PROCEDURE
An electrolyte consisting or aluminum bromide, aluminum chloride, and ethyl bromide in benzene and xylene 2) was first prepared by dissolving AlBr 3 and AlCl 3 in benzene and xylene and adding to the mixture some ethyl bromide. The dark red reaction products were electrolyzed with an aluminum anode and a copper cathode. The bath was investigated to determine the effects of various additional agents, current density and temperature. The purpose was to find the optimum conditions whereat an adherent and bright deposit could be obtained. Copper cathodes and aluminum anodes were used exclusively throughout the investigation. ihe cathodes used were always pickled first with acid, washed with distilled water, and then distilled benzene. After electrolysis they were washed with benzene again.
Simultaneously a search was made to find some other electrolyte from which aluminum could be deposited. Various anhydrous aluminum salts were dissolved in organic solvents and the solutions were tested to see whether they were conducting. In the cases where the solutions were found to be highly - (1-
conducting, they were electrolyzed to see if aluminum could be deposited or not. Attempts were made to form some organo-aluminum complexes which would give high conductances and serve as electrolytic baths. The electric circuit employed for electrolysis was as follows:
(Rhest-t
cei coulaometer A,",-"Ceter
The copper coulometer was used whenever the current efficiencies of the electrolyzing bath were determined.
In the determination of influence or temperature on the nature of the aluminum deposit, the cell was immersed in a constant temperature oil bath regulated by mercury contact control.
In all the above experimental work, great care was exercised in dehydrating the various solvents and salts used, as minute quantities of water may effect the results enormously. Details for the preparation and dehydration of some of the compounds used are given in the appendix. - I -
V. RESULTS AND DISCUSSION
The results of this thesis can be classified under two main headings; namely, (1) Solutions from which aluminum is deposited, and (2) Solutions from which aluminum is not deposited.
A. Solutions from Which Aluminum Is Deposited.
1. AlBr3 , AlCl3 , and EtBr in Benzene and Xylene (2) This is the electrolyte suggested by Blue and
Mathers for aluminum deposition. AlBr3 was first prepared reacting 6.0 g. of Al with 44.0 g. of bromine. The product was fused with 30.0 g. of AlCl 3 ' To this mixture were added 70.0 cc of xylene and 110.0 cc of benzene. A dark colored solution was obtained, to which o5.0 cc of ethyl bromide was added. -UCl gas was given off and two immiscible layers were formed. The bottom layer containing the red reaction products gradually increased in volume as the reaction proceeded. a. rffect of Additional Agents. Various additional agents were added to the electrolyte to see whether bright and adherent deposits could be odtained. The results are given in Table I.
This work was all done at room temperature which was about 25'C. -8 -
Table I
Run Current Time Addition Nature of The Deposit No. Density (Hrs.) Agents
1 .125amp/i 20.0 None Laposit spongy, dark and coarsely crystal- line.
2 *074 " 20.b Added P2 05 Better throwing power; deposit still dark; loose Al particles were found on cathode; the layer of Al under- neath was more adher- ent.
3 .052 " -- Added 40cc Deposit dark, but chloroben- smoother, easily rub- zene; used bed off. N atmos- p.ere.
4 .071 " -- Added a Deposit adherent, less few parti- dark. cles of CaCl and 5cc 9f a colloidal soln. of rubber in benzene (lg.rubber per 100cc benzene). N2 used. 5 .112 " 17.6 bc more Deposit on the side of of the cathode facing the rubber anode was still dark soln. and not very adherent; but back side was bright and adherent; upon buffing, became very shiny. - C -
The results in Table I indicate that rubber, a lyophilic colloid for benzene, has a pronounced
brightening effect on the deposit. The reason that only the back side of the cathode has a bright deposit
is obviously due to the fact that the current density
in the front side is too high. By reducing the current
density, satisfactory deposits can be obtained. The
function of the minute quantity of rubber in this
solution can be considered the same as that of glue in copper plating solutions.
b. Effect of Current Density. From Table I we can already see that lower current density ought
to give better deposits. Several runs were made
at different current densities and the results are
given in Table II. This work was also done at room temperature.
The results in Table II confirm the fact
that lower current density will give a much better
deposit. Deposits at a current density below
.025 amp./in.2 are very satisfactory. The reason that some of the deposits peel off upon buffing is probably that there are occluded electrolytes
in the deposits. This electrolyte if in contact with moisture of if suddenly heated as by buffing will evolve a gas. The last sample, which is very - 10 -
Table II
Run Current Time Other Conditions Nature of The No. Density (ors.) Deposit
*QAQai4./a 23.5 2 more cc rubber Deposit bright solution. and adherent; very shiny upon buffing; but there were pits on surface.
2 .029 " 26 No change Deposit bright and coherent; upon scratching, peeled off like tin foil; less pits.
3 .026 " 22 2 more cc rubber Deposit bright; solution less pits; upon buffing, separat- ed from base metal.
4 .014 " 26.6 No change Deposit bright and at first ad- herent; later scratching peeled it off like tin foil.
5 .013 " 24 No change Deposit bright; some gas develop- ed during buffing and made deposit peel off.
6 .013 " 24 After electroly- Deposit very sat- sis, immediately isfactory, brighz immersed cathode and adherent; no in benzene, pits; upon buff- brushed and wash ing gave silvery ed with benzene, luster. dried in oven at 12b*C. - 11-
satisfactory, is very adherent and bright. Its success may due to the thorough cleaning of the deposit after electrolysis by brushing and washing in benzene.
c. Effect of Temperature: A solution was electrolyzed at a current density of .019 amp./sq.in. and at 4b C. in a constant temperature oil bath.
The conductance was found to increase greatly with the increase of temperature. The result obtained compared with that at room temperature seemed to indicate that lower temperature gives a better deposit. Using a bath of practically the same composition as the one used here, Downie 4 ) claimed that a much higher throwing power was obtained at low temperatures.
d. Current Efficiencies. After two months of usage of the electrolytic bath, the current efficiencies was determined. The anode efficiency was found to be 10b.9 y, while the cathode effi- ciency was only 26.3 7. According to Blue and
Mathers, a cathode efficiency as high as 75 % was
often obtained. In this case the low cathode current efficiency may be due to the fact that during this
long time of usage some moisture might have been
absorbed by the bath. - l2 -
2. AlBr 3, AlC1 3 , and EtBr in Kerosene: The method of preparation of this electrolyte was exactly the same as that of the previous one, except that kerosene, boiling between 150*and 2400C., was used as substitute tor the benzene and xylene mixture.
AlBr 3, prepared from 5 g. of Al and 35.1 g. of bromine, 20.0 g. of AlCl3 and 54 cc of ethyl bromide were used. There was also a separation of two immiseible layers and the formation of a dark red reaction product.
The product this time had a very high viscosity in comparison with the one previously mentioned.
a. Effect of Temperature. The solution was electrolyzed for eighteen hours at room temperature, but no aluminum was deposited at the cathode. At the same time the anode was found to be corroded.
The failure to deposit aluminum was considered to be the result of the extraordinarily high viscosity.
A second run was made at 750C. with a current density of .085 amp./sq.in.. The conductance increased several fold with this increase in temperature. After 21 hours of electrolysis, it was found that aluminum was deposited. However, the amount deposited was very small.
b. .urrent itfficiencies. The cathode current efficiency of this bath was extremely low. Even after - 13 - a long time of electrolysis, only a small amount of aluminum was deposited. It is evidently unsatisfactory to use this solution to deposit aluminum.
3. AlBr 3, AlCl 3 , and EtBr in Xylene: This solution was different from the first one mentioned in that xylene alone was used in its preparation. 5.0 g. Al and 35.1 g. kOr 12 cc) of bromine were used to prepare the AlBr 3. 0.0 g. of
AlCl 3 , 50 cc of ztBr, and 100 cc of xylene were also employed. Hl was given off during the reaction and a similar solution was obtained. The conductance of this solution was found to decrease with the time of electrolysis. 10 cc of benzene was later added and it helped to keep the conductance more or less constant.
a. Current Efficiencies. The cathode current efficiency of this solution was exceedingly low, while the anode efficiency was about a hundred per cent.
Aluminum was not deposited at first. Only after a
long time of electrolysis were traces of aluminum
found on the cathode. It seemed that the aluminum
content in the electrolyte had to accumulate before
any aluminum could be deposited.
z. AlCl and EtBr in Chlorobenzene:
Aluminum chloride is insoluble in chlorobenzene, but if ethyl bromide is added to some aluminum chloride - l4 -
in chlorobenzene, the anhydrous chloride slowly dis- solves with the evolution of a gas. Meanwhile the color of the chlorobenzene solution gradually darkens. There is no separation of immiscible layers. xhis solution has a high conductance and aluminum can be deposited at the cathode.
a. Effect of Colloidal Agents. The colloidal agent employed this time was a solution of some ten- times-milled rubber in xylene. Very little amount was needed to give a pronounced brightening effect. The deposit obtained with the help of rubber at a current density of .044 amp./sq.in. at room temperature was found to be very satisfactory. It was adherent and bright, upon buffing it became very shiny.
b. uCurrent Efficiencies. The cathode current efficiency of this solution seemed to be very h4.&, but owing to the time available, the exact efficiencies have yet to be determined. This solution appears to be very promising.
B. Solutions from which Aluminum Is Not Deposited.
1. AlBr, AlCl3 , and Acetyl Chloride in Benzene: According to Wertyporoch and Firla(16), acyl
chlorides and benzene in the presence of aluminum
chloride undergo rriedel and 6raft reactions, which yield highly conducting complexes. A solution containing such complexes was prepared by dissolving some AlBr3 and AlCl 3 in a mixture of benzene and toluene and adding some acetyl chloride to the mix- ture. The reaction was rather vigorous. neat and
H01 were given off. ihe solution had good conductance, which increased rapidly with temperature. It was electrolyzed for five hours, but no aluminum was found deposited. xhere had been formed around the electrodes some dark gummy substances instead.
2. AlCl3 and stearic Acid in Chlorobenzene:
It had been found that if stearic acid was dissolved in chlorobenzene and aluminum chloride was then added, HC1 gas was given off, yielding a solution which conducted reasonably well. 9.8 g. of aluminum chloride, 63 g. of stearic acid and 200 cc chlorobenzene were used to prepare such a solution.
,he solution was first electrolyzed with a copper cathode and a aluminumanode. During electrolysis, there was a continous gas evolution at the anode. iNo aluminum was deposited at all at the cathode. The electrodes were reversed and tried again. Gopper seemed to have been corroded and some waxy substance was found on the aluminum cathode.
-he solution was elecurolyzed again with two aluminum electrodes. A gas was evolved at the anode and a waxy deposit was found on the cathode. - IC -
If a piece of aluminum was dipped into this solution and dried, a thin waxy layer was also found. Sodium hydroxide attacked both of the waxy layers, but the one which had been electrolyzed seemed to offer much greater resistance toward the alkali.
If aluminum chloride was added to a solution of stearic acid in benzene, a similar reaction occurred, but this solution did not conduct very well. This was considered due to the low dielectric constant of benzene, because if acetone, a solvent possessing a high dielectric constant, was added to the benzene mixture, the resulting solution was found to have a high conductance. However, no aluminum was deposited by electrolysis. The same kind of reaction was observed by using glacial acetic acid instead of stearic acid. Aluminum chloride added to a glacial acetic acid solution in benzene liberated some HCl. If acetone was then added, the solution possessed high conductance. But no aluminum was found deposited.
Owing to the fact that aluminum was not deposited from these solutions, it was suspected that the reaction was not a simple metathesis between aluminum chloride and the acid liberating some volatile hCi but owing to the time available these solutions were not studied any further. 3. AlCl 3 in Nitrobenzene: Aluminum chloride was found to be very soluble in nitrobenzene. Owing in part to the high dielectric constant of nitrobenzene, the solution was found to have a high conductance. Electrolysis of this solution, however, failed to give any aluminum. During electrolysis the solution became darker and darker, indicating the presence of some other reaction. Conductivity decreased steadily with the time of electrolysis and there seemed to be considerable polarization.
4. Other Aluminum Salts in various Solvents:
Various aluminum salts, both of organic and in-
organic acids, were dehydrated and dissolved in various organic solvents. The solubilities of these salts in
the solvents used were usually very small. No effort was made to determine them quantitatively. These solu-
tions were tested to see if they conducted any current. &he conductivities were usually very small. The
results are tabulated in Table III.
From Table III, we can see that the acetone solu-
tions conduct better than the rest. Lithium nitrate
added to aluminum nitrate in acetone increases the
conductance of the solution. But electrolysis of it
failed to deposit any aluminum. The other solutions of acetone were not electrolyzed, because of the fact that - 18 -
Table III Salt Solvent Solubility Gonductance
Aluminum Toluene Negligible Negligible benzoate
Aluminum Toluene Negligible oxalate Negligible
alminum Xylene Negligible Negligible beuinut Morpholine Negligible Negligible
Aluminum Morpholine Negligible Negligible oxalat e
Aluminum acetate Morpholine Very little Negligible (basic)
Aluminum Morpholine iiegligible Negligible nitrate
Aluminum Acetone Very low Low oxalat e
Aluminum Actn benzoate AeoeVery low Low
Aluminum Acetone Low Low nitrate
Al(NO 3 )3 Much higher than + LiNO Acetone ----- 3 Al(NO 33 alone. Aluminum Ethylene Low Low nitrate diamine L_ _ _Lo_
Al(NO 3)3 Dioxane Very low Negligible - 19 -
their conductivities were too low in comparison with the solutions that had been used for aluminum de- position.
Aluminum nitrate in ethylene diamine had a moderate conductance, but this solution was likewise not electrolyzed.
From the experimental results, we find that
solutions of merely aluminum salts in solvents usually
have very low conductivities, even if the solvent may possess a very high dielectric constant. On the other hand, solutions containing organo-aluminum
complexes usually have high conductivies, even if
the solvent have only a low dielectric constant, such a benzene. - 20 -
VI. CONCLUSIONS
From the results and discussion, the following conclusions are drawn:
1. Aluminum can be deposited from organic solu- tions to give an adherent and bright plate.
2. The most suitable electrolytic baths are:
a. A solution containing the reaction products of AlBr3 , AlCl, and'EtBr in benzene. b. A solution containing the reaction products of AlCl 3 and EtBr in chlorobenzene. 3. Rubber, a lyophilic colloid for benzene, has a pronounced brightening effect on the aluminum deposit, and only a very small amount is needed to give the effect.
4. Lower current density gives better deposit. b. solutions containing organo-aluminum complexes usually have much higher conductivities than solutions of merely aluminum salts in solvents. - 21 -
VII. RECOMMENDATIONS
For aluminum deposition it is recommended that either a solution of AlBr 3, AlCl3 , and EtBr in benzene or a solution of AlCl3 and EtBr in chlorobenzene should be used. The solutions should contain a little rubber, either milled or unmilled, and be electrolyzed at low current densities.
There is still a great deal of work to be done on this subject, especially on the solution containing the reaction products of AlCl 3 and EtBr in chloro- benzene. it has hot been studied thoroughly. Similar solutions may be prepared and investigated.
DETAILS OF THE PREPARATION AND DEHYDRATION OF SOME OF THE COMPOUNDS USED
1. Preparation or Aluminum Bromide: Anhydrous aluminum bromide was prepared by the direct union or aluminum and bromine. The app atus used consisted of a pyrex flask fitted with a reflux condenser. The cork joint was protected from the action of the bromine by several layers of aluminum foil. Aluminum turnings instead of aluminum powder was used in order to avoid too violent a reaction.
T6he bromine was introduced through the condenser into the flask by the use of a dropping funnel located at the top of the condenser. The drops were allowed to fall only at a moderate rate. The flask was cooled with a water bath to prevent too high a temperature.
2. Preparation of Blue and Mathers' Bath:
The aluminum bromide as prepared above was not taken out of the flask. Aluminum chloride was then added to it and the mixture fused together to make the aluminum chloride dissolve easier in benzene. The melt was allowed to cool and solidify. A mixture of ben-
zene and xylene was then added and the flask was warmed by heating the water bath. After most of the solids had dissolved, the mixture was allowed to cool to room - 23 -
temperature again. Ethyl broihide was then added
through the reflux condenser. The mixture was
allowed to stand until the reaction ceased. 3. Preparation of Aluminum benzoate: Aluminum benzoate was prepared by simple metathesis between aluminum chloride and sodium
benzoate. The aluminum chloride solution was made
by dissolving hydrated aluminum chloride crystals
in water. The precipitated aluminum benzoate was thoroughly washed and dried.
4. Dehydration of Some of The Compounds Used: The methods of dehydration for some of the
compounds are given in Table IV on the following
page. Table IV
Compounds Methods of Dehydration
Ethyl bromide Dried over CaCl2
Benzene Dried by sodium wire
Toluene I It it
Xylene it i i
Aluminum oxalate Dried in an oven at about 110*C.
Aluminum benzoate Dried in oven at about 110"C
Morpholine Refluxed with NaOH, distill- ed and dried further with a little sodium wire.
Chlorobenzene Dried over CaCl2
Aluminum basic Dried in oven at about 110*C acetate
Aluminum nitrate " " " " " "
Acetone Dried over anhydrous K2 C0 3
Kerosene Dried over OaCl2 and distill ed over sodium.
Nitrobenzene Dried over CaCl2 APLENDIX B 25
ORIGINAL DATA
1. Composition of The Blue and Mather Bath: Aluminum ...... 6.0 g • Bromine ...... 15.0 cc AlCL,u anhydrous...... 30.0 g. 0 _l:!;tBr .... b5.0 cc Benzene ...... l~O.O cc Xylene ...... 70.0 cc
2. Composition of 1l 1he Kerosene Solution: Aluminum ...... 5.0 g • Bromine (De~sity= 2.93) .. . . . 12.0 cc A1Cl 20.0 3 ...... g • EtBr •• ... 54.0 cc Kerosene ..... 165.0 cc
3. Composition of T~~ne Solution:
Aluminum b.O g. .l:)romine 12.0 cc 30.0 g. 50.0 cc Xylene ...... 190.0 cc
4. Composition of The Acetyl Chloride Solution: Aluminum . . . . . 5.0 g • Bromine ...... 11.0 cc AlC1 •••• 15.0 g • 3 . . . . . Benzene ... 200.0 cc Toluene ...... 60.0 cc Acetyl chloride •• ...... 50.0 cc 5. Composition of The AlCl3, And Stearic Acid Solution:
Aluminum chloride...... 9.8 g. Stearic acid ...... 63.0-g. Chlorobenzene...... 200.0 cc
6. Oomposition of The Copper Coulometer Solution:
CUSO4* 5 H 20 ...... 75.0 g. Distilledi e...... bOO.0 cc Ethyl alcohol...... 30.0 cc Conc. h25 0'...... l.0 cc
7. Determination of Efficiency of The Blue and
Mathers' Solution: Before electrolysis:
Weight of aluminum anode ...... 4.5416 g. Weight of Cu cathode ...... 27.4242 g. Weight of Cu cathode in coulometer.. 23.0130 g. After electrolysis:
Weight of aluminum anode...... 4.1790 g. Loss in weight ...... 3626 g. weight of Cu cathode...... o. 27.5142 g. Gain in weight ...... 0900 g. Weight of Cu cathode in coulometer.. 24.2250 g. Gain in wieght ...... 1.2120 g.
8. Determination of Efficiency of The Xylene Solution: Before electrolysis:
Weight of aluminum anode...... 4.5322 g. Weight of copper cathode...... 30.6656 g. Weight of Cu cathode in coulometer.. 21.2642 g. - 27 -
After electrolysis:
Weight of Aluminum anode ...... k.2100 g . Loss in weight...... 3222 g weight of Cu cathode...... 30.6732 g Liain in weight ...... u076 g Weight of Cu cathode in coulometer.. 22.3596 g uain in weight ...... 1.0954 g
9. Sample Calculations for Efriciency:
Let ea = anode efficiency ec = cathode efficiency
AW= gain in weight AW' = loss in weight
N = number of Faradays passed
CAl = equivalent weight of Al
CCu = equivalent weight of Ou From coulometer:
N = AW/C Su 4W' . . e a x 100% (1) N x CAl AW and e x 100% c N x CAl
CCu = 63.57/2 26.97/3 0 Al =
Substituting the numerical data in eqs. (1) and (2), we obtain: - 28 -
Table V
Current Efficiency Anode Cathode
AlBr 3, A101 3 and EtBr in benzene 105.9% 26. 6 solution.
Xylene Solution 10-*.2% 2.b5
10. Conductances of The Two Above Solutions As
Measured by O. Rosas+:
Table VI
Solution Specific Specific Resistance Conductance (ohms) (mhos)
AlBr3 , AlCl3 and EtBr -in benzene soln., after 2 mon, 1118 .00089 of usage.
Xylene Solution 710 .0011l
The measurements were made at 26+ .020 C.
+C. Rosas; "Conductivities of Some Non-aqueous
Electrolytes"; Bachelor Thesis, Chem. Eng'g., M.I.T. (1939). APPENDIX 0 - 29 -
ESCRIPTION OF THE ELECTROLY'IC COLL USED
In Fig. 2 a diagram of the electrolytic cell used is shown in detail. It consists of a glass bottle fitted with a tight - rubber stopper.
Two holes are drill- - ubbe*'u 9 ed through the stopper C,' ,ber s1;o~fer and two short pieces of glass tubing are inserted tightly in them. At the end of the tube a short piece of rubber tubing is attached. he electrodes in the solution are connected with the outside circuit by means of the leads that pass through these tubings. .he rubber tubing is clamped as tight as possible by two screw clamps. In this way, the moisture in the air is prevented from being absorbed by the solution.
In some or the runs, a nitrogen atmosphere was employed. In these cases, two more holes are drilled through the rubber stopper . Through one of them a long glass tibe is inserted, extending into -30 - the solution. .he other hole is connected by means of a short glass tube to a calcium chloride drying tube. The nitrogen arter being purified is introduced through the longer glass tube. Slow but continuous bubbling is maintained. APPENDIX D - 31 -
BIBLIOGRAPhY
1. Blue, R.D., and kathers, *.C.; Transactions or The Electrochemical 0ociety, 65, 1 pp. preprint (1934).
2. blue, R.D., and Mathers, r*.C.; "Aluminum 1''lating
from Organic Baths", Trans. Electrochem. soc., 69, pp. 519-27 (1936).
3. Dirkse and Briscoe; Metal Industry, 36 , no. 6, p. 28=' (1938).
'. Downie, Q.C.; Metallurgia, 18, no.106, p.13* (1938). o. uuilford, L.e.; "Electrodeposition of Aluminum", S.B. Thesis, Ulectrochem., M.I.T. (1930).
6. ieyes, Swann, tlabinde and Schicktanz; Ind. ng. Qhem., 20, 1068-9 (1928).
7. Keyes, 'hipps and Klabinde; pa-. U.S. 1,911,122, May 23, 1933.
8. Khakin; pat. Russ. 28,481, June 30, 1933.
9. Lalbin, E.L.; pat. brit. 106, *00 , September 23, 1916.
10.Mfiller, H81zl, &naus, Flaniszig and Frett; Monatsh., , pp. 219-36 (1924). ll.Plotnikoff, W.A.; J. tuss. Phys. Chem. Soc., 3
p. *66 (1902). - 62 -
12. Plotnikov and Podorvan; Mem. Inst. Chem. All-
Ukrain. Ac~d. Sci., 1 , pp. 34-42 (1934).
13. Patten, H.E.; Trans. Am. Electrochem. Soc., 6J, p. 9 (190 ). 1l. Quintin Marino and Darlington Wire Mills Ltd.;
Brit. O0bb33 , eeb. 8, 193,*. lb. Wertyporoch, Eugen; Ber., 64B, pp. 1369-80 (1931).
16. Wertyporoch, E., and Firla; Ann., 500, p.287
(1933).