1,3-BUTADIENE SELECTIVE HYDROGENATION OVER PD ALUMINA AND CUPD/ALUMINA CATALYSTS/

The selective hydrogenation of 1,3-butadiene was studied in the presen ce of a 10:1 excess of 1-butene over supported bimetallic catalysts co ntaining palladium in a vapour phase atmospheric plug flow reactor in the temperature range 288-313 K. Addition of copper to alumina-support ed Pd increases its selectivity for converting butadiene to n-butenes without saturating or isomerizing the n-butenes. For example, with ato mic ratio Cu/Pd=2, the bimetallic catalyst selectively converts >99% o f the diene to n-butenes while isomerizing or saturating less than 1% of the starting I-butene. Under similar conditions, Pd alone maintains high n-butene selectivity to only about 50% conversion of the diene. Over both catalysts the kinetics of 1,3-butadiene hydrogenation are fi rst order in hydrogen and zero order in butadiene. Hydrogen sorption e xperiments showed that Cu addition decreases both the surface adsorpti on and the bulk absorption, the former suggesting surface decoration o f Pd by Cu and the latter indicating significant bulk Cu-Pd interactio n in the supported bimetallic samples.