Palladium assisted copper/alumina catalysts for the selective hydrogenation of propyne, propadiene and propene mixed feeds

Abstract

A series of copper rich catalysts with different Cu:Pd atomic ratios were screened for the selective hydrogenation of propyne. Sample with 50:1 Cu:Pd ratio exhibited high propene selectivity, yet could be operated at temperatures far lower than typically observed for Cu only catalyst. It is believed that Pd facilitates reaction at Cu sites by promoting hydrogen dissociation at low temperature, followed by spillover onto Cu where the reaction occurs selectively. Catalyst testing with propyne alone showed that full conversion could be achieved at only 383K with greater than 70% selectivity to propene. Industrially relevant tests were also conducted with a mixed C3 feed containing propyne, propadiene, propene and propane which is unique given that most literature studies fail to consider that propadiene is also an impurity which must be removed during selective hydrogenation of C3 cuts from naphtha crackers. Under such conditions and at only 383K, propene selectivity of around 90% was achievable at >99% conversion. The option to operate at such low temperature, in the absence of CO, makes 50-CuPd sample an interesting alterative to current industrial catalysts.