Electrochemical reduction of unsaturated nitriles in acetonitrile and nitromethane

• Published in: Electrochimica acta Vol. 39; no. 13; pp. 2067 - 2071
• Main Authors: Becker, James Y., Koch, Theodore A.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.09.1994; Elsevier
• Subjects: Chemistry; cyanonitroalkanes; dinitriles; Electrochemistry; electrohydrodimerization (EHD); Exact sciences and technology; General and physical chemistry; Kinetics and mechanism of reactions; unsaturated nitriles; cyanonitroalkanes; electrohydrodimerization (EHD); unsaturated nitriles; dinitriles; Unsaturated compound; Chemical reduction; Nitrile; Hydrodimerization; Acetonitrile; Reaction mechanism; Experimental study; Electrochemical reaction; Aprotic solvent
• ISSN: 0013-4686; 1873-3859
• DOI: 10.1016/0013-4686(94)85090-9

The electrochemical reduction of five conjugated and non-conjugated nitriles, CH 3CHCHCN ( 1a, trans/cis = 62/38%); CH 3CH 2CHCHCN ( 1b, cis); CH 3CHCHCH 2CN ( 1c, trans), CH 3CHC(CH 3)CN ( 1d) and CH 2CHCH(CH 3)CN ( 1e) have been investigated in acetonitrile, and of two derivatives, 1a and CH 2C(CH 3)CN ( 1f) in nitromethane. The results show that unlike activated nitriles which undergo the known electrohydrodimerization (EHD) process in protic media, forming “tail-to-tail” dimeric products, the dimerization in acetonitrile affords mainly “head-to-tail” dimers and other products involving addition of “H” and “CH 2CN” moieties to the carbon—carbon double bond. Moreover, it is noteworthy that the electrochemical dimerization in acetonitrile affords branched dinitriles with an odd number of carbons between the two nitrile groups, rather than the common dimers with an even number of carbons. This type of dimer could serve as a precursor for branched diamines (and diacids) in the polyamide industry. In nitromethane, no dimeric but “condensation” products were formed, involving one molecule of solvent and one or two molecules of nitrilic substrate.