KINETICS OF HYDROGENATION OF CINNAMALDEHYDE OVER ALUMINA-SUPPORTED BIMETALLIC PD-PT AND PD-RH CATALYSTS

Kinetics of hydrogenation of cinnamaldehyde over Pd50Pt50 and Pd40Rh60 supported on Al2O3 have been studied. GC analysis and UV/vis spectrop hotometric measurements have been used to identify the products and de termine their concentrations. The products of this reaction, 3-phenylp ropanal, 3-phenylpropanol and propylbenzene, are produced consecutivel y. The rate constants of the first step of this reaction over Pd50Pt50 /Al2O3 and Pd40Rh60/Al2O3 are 1.88 X 10(-2) M(-1.5) s(-1) g(-1) (metal ) and 2.46 X 10(-2) M(-1.5) s(-1) g(-1) (metal), respectively. The rea ction order is 1 with respect to cinnamaldehyde and 1.5 with respect t o hydrogen. The temperature variations in the range of 27-41 degrees C have no significant effect on the reaction rates of both catalysts.