HYDROGENATION OF SORBIC ACID-CATALYZED BY A DIHYDRIDORHODIUM COMPLEX

The homogeneous hydrogenation of sorbic acid catalyzed by dihydrido(1, 3-diphenyltriazenido) bis (triphenylphosphine) rhodium (III) (dihydrid orhodium complex) in several solvents was studied under a 1 atm pressu re of hydrogen at 50-degrees-C. The catalytic hydrogenation activity w as found to decrease in the following order: Dimethyl sulfoxide (DMSO) >> N,N-Dimethylformamide > Acetone > Benzene = Toluene > Tetrahydrofu ran. The hydrogenation of sorbic acid with dihydridorhodium complex in the range of 30 to 60-degrees-C has been studied in DMSO. Main produc t obtained was trans-2-hexenoic acid at 30 and 40-degrees-C, and trans -2-hexenoic acid was further hydrogenated to hexanoic acid at 50 and 6 0-degrees-C. The apparent overall activation energy for the hydrogenat ion of sorbic acid with dihydridorhodium complex was estimated to be 5 1.0 kJ mol-1.