Hydrogenation of Sorbic Acid Catalyzed by a Dihydridorhodium Complex

Abstract

The homogeneous hydrogenation of sorbic acid catalyzed by dihydrido (1, 3-diphenyltriazenido)bis (triphenylphosphine) rhodium ( DI ) (dihydridorhodium complex) in several solvents was studied under a 1 atm pressure of hydrogen at 50°C. The catalytic hydrogenation activity was found to decrease in the following order:
Dimethyl su lfoxide (DMS0) > N, N-Dimethylformamide > Acetone > Benzene = Toluene > Tetrahydrofuran.
The hydrogenation of sorbic acid with dihydridorhodium complex in the range of 30 to 60°C has been studied in DMSO. Main product obtained was trans-2-hexenoic acid at 30 and 40°C, and trans-2-hexenoic acid was further hydrogenated to hexanoic acid at 50 and 60°C. The apparent overall activation energy for the hydrogenation of sorbic acid with dihydridorhodium complex was estimated to be 51.0kJ mol^-1.