366 PROFESSOR A. CRUM BROWN AND DR JAMES WALKER ON THE 



From 200 grammes of diethyl dimethylmalonate, after half-saponification and electro- 

 lysis, we obtained about 60 grammes of an ethereal product. On fractionation this gave 

 nearly 40 grammes of an oil boiling above 200°, of which the greater part went over 

 between 240° and 250°. This fraction was heated for twenty hours to 110° with its own 

 volume of fuming hydrobromic acid (sp. gr. 17), following the method of Auwers and 

 V. Meyer. 



The product was then neutralised with caustic soda solution and distilled with steam, 

 when bromide of ethyl and unattacked ether distilled over. The solution remaining in 

 the flask was acidified and again distilled with steam. Part of the distillate solidified in 

 the condenser in white crystals. When nothing more passed over with the steam, the 

 whole distillate was dissolved in caustic potash, evaporated to a small volume, and pre- 

 cipitated with hydrochloric acid. The acid was separated by filtration, and several times 

 recrystallised from water. The acid is pretty readily soluble in hot, very slightly in cold 

 water. It dissolves readily in alcohol and in benzene, less easily in ether, and is nearly 

 insoluble in cold ligroin. Combustion gave results agreeing with the formula C 8 H 14 4 

 (tetramethylsuccinic acid) : — 



01323 gramme substance gave 0"2669 gramme C0 2 and - 0947 H 2 0. 

 Calculated for C 8 H M 4 . Found. 



C 5517 55-02 



H 805 796 



A basicity determination gave results agreeing with the formula C 6 H 12 (COOH) 2 : — 



01102 gramme acid required for neutralisation 1213 cc. l/9'45 normal baryta water. 



Calculated for C 6 H 12 (COOH) 2 . Found. 



Carboxyl-hydrogen . . 1150 1165 



When quickly heated, the acid fused, with decomposition, at 195°. Auwers and 

 Meyer (loc. cit.) obtained for the fusing-point of tetramethylsuccinic acid temperatures 

 varying from 190° to nearly 200°, according to the rate at which the acid was heated. A 

 small portion of the acid was converted by boiling into the anhydride, which, after re- 

 crystallisation from hot ligroin, formed fine needles, fusing at 147°-148°. 



Tetramethylsuccinic anhydride fuses at 147°. 



The dissociation constant was determined with the following result : — 



Tetramethylsuccinic acid prepared by electrolytic synthesis. 





COOHC(CH 3 ) 2 C(CH 3 ) 2 -COOH. 









Moo =348. 





V 



^ 



100m 



K 



86 



52-6 



151 



00313 



172 



71-6 



206 



00310 



344 



96-8 



27-8 



0311 



688 



1277 



367 

 K = 00311. 



00310 



Berichte der deutsche chemische Gesellschaft 23, 298. 



