LIQUID-PHASE HYDROGENATION OF CARBOXYLIC-ACID ON SUPPORTED BIMETALLICRU-SN-ALUMINA CATALYSTS

Heterogeneous Ru-Sn catalysts are effective for the liquid-phase hydro genation of C=O group in carboxylic acids. Hydrogenation activity was affected by the kind of tin compounds used for the preparation of the Ru-Sn catalyst. Bis-tributyl tin oxide ((Bu3Sn)(2)O), K2SnO3 and Na2Sn O3 were found to be the appropriate materials for the hydrogenation of C=O group over the Ru-Sn catalysts. The C=O hydrogenation activity fo r the hydrogenation of carboxylic acids increased with the increasing amount of Sn added whereas, the C=C hydrogenation activity decreased. Effect of activation temperature was also studied. The C=O hydrogenati on activity was increased by calcinating the catalyst precursor, Sn/al umina, before impregnation with Ru solution. The calcination of the Sn /alumina at 973 K was quite effective for the hydrogenation of carboxy lic acids over the resultant Ru-Sn/alumina catalysts. The Ru-Sn/alumin a catalysts reduced at 723 K were also effective for the hydrogenation of carboxylic acids. We have also studied the hydrogenation in a cont inuously flowing system. The Ru-Sn/alumina catalysts showed high and s table activity under mild conditions in the flowing system.