1890-91.] Prof. Brown and Dr Walker on Dibasic Acids . 95 
Electrolytic Synthesis of Dibasic Acids. Alkyl Deriva- 
tives of Succinic Acid. By Professor Crum Brown 
and Dr James Walker. 
(Read April 6, 1891.) 
{Abstract.) 
In onr previous communications to the Society (see Trans. 
xxxvi. 211) we described the behaviour of the ethyl potassium 
salts of normal dibasic acids on electrolysis. These we found 
always to yield the diethyl esters of normal acids of the same 
series. We have now extended our investigation to acids with 
side chains, and in this paper give an account of the electrolysis 
of ethylpotassium methylmalonate and ethylpotassium ethyl- 
malonate. 
The esters formed according to the general equation, 2EtO(CO). 
R".(C0)0- = EtO(CO).R".R".(CO).OEt + 2C0 2 , are evidently 
always symmetrical, so that from methylmalonic acid we should 
expect to obtain symmetrical dimethylsuccinic acid : — 2EtO(CO). 
CH(CH 3 ).(C0)0- = EtO(CO).CH(CH 3 ).CH(CH 3 ).(CO)OEt + 2C0 2 . 
This dimethylsuccinic acid contains two similarly si luated asym- 
metric carbon atoms, and is thus, like tartaric acid, capable of 
existence in four isomeric forms — two optically active, and two 
optically inactive, one of these latter (corresponding to racemic 
acid) being a compound or mixture in equal proportions of the 
two opposite optically active acids. As the optically active forms 
are produced in equal proportions by any purely chemical process 
from inactive materials, we were justified in expecting to obtain 
by electrolysis a mixture of the esters of the two inactive 
symmetrical dimethylsuccinic acids. 
The synthesis was conducted in precisely the same manner as 
in our previous experiments. 150 grams of ethylpotassium methyl- 
malonate yielded about 60 grams of an ethereal product, which, 
on distillation, gave a fraction of 30 grams, boiling between 194° 
C. and 206° C. This portion was saponified with boiling alcoholic 
potash, and the potassium salt thus formed converted into the 
