Maleic acid, electroreduction

In addition to the above-listed systems, a minimum of the rate constant was observed for the Zn(II)/Zn(Hg) systems in water-methanol [232] and for the Mn(II)/Mn(Hg) systems in water-acetonitrile mixtures [230]. Electroreduction of T1(I), Zn(II) and maleic acid was also studied in water-acetone [273] and water-ethanol [274] mixtures. 

The first step of electroreduction of maleic acid (M) on Hg was reported to be electron transfer forming an ion radical, followed by addition of H ... 

Recently, the possible preparation of different stereoisomers by preparative electroreduction at a controlled potential and pH was derived from polarographic data. Thus for a, a -dibromosuccinic acids, the erythro-form of the free add and of its anions is reduced to fumaric acid. On the other hand, the threo-epimer is reduced to the fumaric acid only in an undissodated form and as a dibasic anion the univalent anion is at least partly reduced to maleic acid. Both threo- and erythro-epimers of dialkyl esters of dibromosuccinic acid are reduced only to the dialkyl ester of fumaric acid—similarly to the undissodated free adds. ... 

Electrochemical membrane reactors have also been used in fine chemistry reactions. The electrochemical reduction of maleic acid to succinic add has been reported by using a sulfonated poly(styrene divinylben-zene) membrane intercalated between copper and lead anodes, assembled in a continuous contactor-type membrane reactor. Montiel et al. have recently described the use of MEA technology for the synthesis of N-acetyl-L-qrsteine by electroreduction of N,N-diacetyl-L-qrstine. 

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