1892-93.] Prof. C. Brown and Dr J. Walker on Synthesis. 243 
Synthesis by Means of Electrolysis. By Professor 
Crum Brown and Dr James Walker. Part VI. 
(Read January 10, 1893.) 
Abstract. 
Synthesis of Tetramethylsuccinic Acid. — Ethyl-potassium dime- 
thylmalonate cannot be prepared from dimethylmalonic ether by 
following precisely the method which succeeded in all previous 
cases. When the ether is mixed, either at once or slowly, with 
the calculated quantity of caustic potash in alcoholic solution, half 
of the ether is completely saponified, while the other half is un- 
acted on, only an insignificant fraction being half-saponified and 
converted into the ethyl-potassium salt. A good yield of the latter 
was, however, obtained by a modification of the process, the 
special points of which were great dilution with alcohol and low 
temperature. 
By electrolysis of the ethyl-potassium salt in the manner described 
in former papers, an ethereal product was obtained, of which a large 
part boiled between 240° and 250°. This portion was mixed with 
its own volume of fuming hydrobromic acid and heated for twenty 
hours to 110°. The product was neutralised with caustic soda and 
distilled with steam, when ethyl bromide and some undecomposed 
ether distilled over. What remained in the distilling flask was 
then acidified and again distilled with steam. Part of the distillate 
solidified in the condenser in white crystals. What remained in 
the flask was dissolved in potash, evaporated to a small bulk, and 
decomposed with acid. The acid thus obtained was filtered off and 
purified by recrystallisation from alcohol. It was very slightly 
soluble in cold, considerably more in hot water : easily soluble in 
alcohol and benzene, less so in ether. Combustion gave the follow- 
ing results : — 
0‘1323 gramme substance gave 0'2669 gramme CO 2 and 0'0947 
gramme H 2 O. 
Calculated for C 8 H 14 O 4 . 
Found. 
55-02 
7-96 
C 
H 
55-17 
8-05 
