ELECTROLYTIC SYNTHESIS OF DIBASIC ACIDS. 367 



This value agrees well with that obtained by Bethmann * for Auwers and Meyeb's 

 acid, viz., K = 0*0314. 



Electrolysis of Ethyl-potassium Diethylmalonate. 



Ethyl-potassium diethylmalonate behaves, when treated with alcoholic caustic potash, 

 exactly like the corresponding dimethylmalonate. 



From 230 grammes of the ethyl-potassium diethylmalonate we obtained, by electro- 

 lysis, 120 grammes of an ethereal product, which we fractionated under atmospheric 

 pressure. In this case the chief part distilled at a comparatively low temperature. 

 There remained in the flask about 40 grammes of a residue with a boiling-point above 

 230°. We distilled this residue under reduced pressure. After repeated fractiona- 

 tion we obtained 18 grammes boiling at about 170° under a pressure of 12 mm. of 

 mercury. The colourless and somewhat viscid oil thus obtained was presumably diethyl 

 tetraethylsuccinate, and we therefore attempted to saponify it. But it remained prac- 

 tically unchanged after prolonged boiling with strong alcoholic potash. This was, how- 

 ever, not altogether surprising considering the difficulty with which tetramethylsuccinic 

 ether is attacked by caustic potash. We therefore tried to saponify it by heating it in 

 sealed tubes with fuming hydrobromic acid, but here also we obtained only traces of an 

 organic acid, but considerable quantities of a neutral substance which will be described 

 later. Attempts with other saponifying a.gents did not lead to the expected result. 

 It was plain that the substance could no longer be supposed to be tetraethylsuccinic 

 ether, and we attempted to purify it by distillation under reduced pressure in order to 

 determine its composition. We obtained a product with constant boiling-point, and 

 analysed it with the following results : — 



I. 01 194 gramme substance gave 0*2845 gramme C0 2 and OT076 gramme H 2 0. 

 II. - 2193 gramme substance gave 0*5230 gramme C0 2 and 0T965 gramme H 2 0. 



Calculated for C 14 H 26 4 . Found. 





I. 



II. 



6512 ' 



64-98 



6503 



1008 



1001 



9-97 



c 



H 



The substance was therefore not diethyl tetraethylsuccinate C 16 H 30 O 4 , which contains 

 67*13 per cent, carbon and 10*48 per cent, hydrogen, but a compound containing two 

 atoms of carbon and four atoms of hydrogen less than this, namely, C 14 H 26 4 . We are 

 unable as yet to give any satisfactory explanation of the constitution of the substance or 

 of how it is produced. It is perfectly neutral, is insoluble in water, mixes with alcohol 

 and ether, and has a specific gravity of 1*0082 at 13°*5 compared with water at 4°. 

 Diethyl tetramethylmalonate is miscible at ordinary temperatures with fuming hydro- 

 bromic acid (sp. gr. 1*7) ; the substance C 14 H 26 04 is insoluble at ordinary temperatures in 



* Zeitschrift filr Physilcalische Chemie 5, 404. 



