Effect of Hydrocarbonaceous Deposits on Competitive Hydrogenation of 1,3-Butadiene and Propene over Pd Catalyst

Gas phase hydrogenation of 1,3-butadiene, propene, and mixtures of 1,3-butadiene and propene has been investigated over 0.05 wt% Pd/Al 2 O 3 catalyst. The catalyst was deliberately poisoned by methane (513 K) or diene (473 K) and the effect of the hydrocarbonaceous materials was tested on the product selectivity and the rate of hydrogenation of diene–propene mixtures. It has been concluded that a large quantity of hydrocarbonaceous deposit decreases the surface fugacity of diene due to transport hinderance and in consequence enhances the over-hydrogenation of diene and permits the hydrogenation of propene in the presence of diene.