The kinetics of methyl sorbate hydrogenation

Methyl trans-2-hexenoate was prepared with a two-step synthesis from trans, trans-2,4-hexadienoic acid (sorbic acid). The first step was the methanol e sterification of sorbic acid catalyzed with sulfuric acid. The second step was a catalytic hydrogenation of the resulting methylester using metallic c atalysts based on Pt, Pd, Rh and Ni carried on an activated carbon and gamm a-alumina. During the hydrogenation reactions, in all cases, monoolefinic m ethyl trans-2-hexenoate was produced as the main reaction intermediate. Var ied isomers of methyl 3- and 4-hexenoates resulted from the reactions as th e side intermediates. The resulting intermediates further hydrogenated to a common product, methyl hexanoate. Palladium was the most apposite catalyst , due to its high activity and significant selectivity to the production of methyl trans-2-hexenoate. At the end, the raw intermediate was rectificate d under the atmospheric pressure. (C) 1999 Elsevier Science B.V. All rights reserved.