Septkmbek 30, 1898.] 



SCIENCE. 



417 



testing the suggestion of Carstanjen that 

 six isomeric allylenes really existed. With- 

 out entering into details, I may say that 

 itaconic acid was electrolyzed with ease; 

 its gaseous products were allylene and car- 

 bon dioxide. The residue contained acrylic 

 and mesaconic acids. The resulting ally- 

 lene was completely absorbed by bromine, 

 but not by an ammoniacal silver nitrate so- 

 lution. Citraconic acid yielded allylene, 

 containing hydrogen exchangeable for metal 

 and acrylic and mesaconic acids. Similar 

 products were discovered in the electrolysis 

 of potassium mesaconate. 



Mesaconic and citraconic acids bearing 

 the same relation to one another as fumaric 

 acid sustains to maleic acid, they, of course, 

 yielded allylene, CH,. C s CH, whereas it- 

 aconic acid was resolved by the current into 

 symmetrical allene, CH^ = C = CH^. 



As we search further we shall discover 

 that under the influence of the electric cur- 

 rent butyric acid was observed to give hex- 

 ane ; valeric acid, octane ; caproic acid, de- 

 cane, etc. Oxalic acid was completely 

 changed to carbon dioxide and water. Ma- 

 lonic acid was resolved into the same com- 

 ponents, but the dissociation proceeded less 

 rapidly. Upon electrolyzing an alkaline 

 solution of sodium succinate Bourgoin ob- 

 served ethylene and acetylene in addition 

 to the customary gas products. Free malic 

 acid was decomposed very slowly ; its alkali 

 salts yielded carbon dioxide, monoxide, 

 oxygen, aldehyde and acetic acid. Tartaric 

 acid was broken down into acetic acid. 

 Lactic and sarcolactic acids, in neutral so- 

 lution, gave acetaldehyde, while in alkaline 

 solution, owing to the condensing power of 

 the alkali, aldol or crotonaldehyde appeared. 

 Glyceric acid was resolved into formalde- 

 hyde, carbon dioxide, monoxide and water. 

 In the case of the electrolysis of /3-hydroxy- 

 acids the rule seems to have been oxidation; 

 the possibility of condensation, however, 

 was not excluded. Formaldehyde was ob- 



tained in very appreciable quantities in the 

 electrolysis of a concentrated solution of 

 glycollic acid, whereas in dilute solution the 

 products were carbon dioxide, carbon mon- 

 oxide and very little formaldehyde. 



Let us pause a few moments and consider 

 how these decompositions have possibly oc- 

 curred. Kolbe considered the course of the 

 action as very evident. The equation pre- 

 viously given represents his idea : " the 

 acetic acid in the field of the galvanic action 

 is oxidized by the oxygen so that it is re- 

 solved into carbon dioxide and methyl, both 

 of which appear at the positive pole, while 

 only hydrogen is formed at the negative 

 electrode." 



Kolbe, Kekul6 and others regarded the 

 decomposition of the organic acid as a sec- 

 ondary reaction. The oxygen arising in 

 the water decomposition they considered 

 exerted an oxidizing effect upon the acid. 

 Bourgoin's researches upon the electrolysis 

 of organic acids were very extensive, and it 

 was the opinion of this investigator that 

 the most important phase in their electrol- 

 ysis was the production of intermediate 

 anhydrides of the acids. These, Bourgoin 

 thought, then parted with oxygen, and sec- 

 ondary products were formed. In this 

 latter class he included the passage of the 

 anhydride into the acid by water absorp- 

 tion, as well as the oxidation of the acids 

 by the oxygen released from the acid. 



These ideas represented by symbols 

 would appear as follows : 



CHs COOjK 

 cHs-cooIk 



CH.CO 



>0+o;+K2 



or 



CH3 

 3. I +CO2+O. 

 CH3 



But we continue to ask : Are an anhydride 

 and oxygen formed before the hydrocarbon 

 is produced ? If so, does the oxygen then 

 decompose the anhydride with the forma- 

 tion of the hydrocarbon and carbon dioxide? 



