PD/AU SHELL CATALYST CONTAINING Hf02, PROCESSES FOR THE PREPARATION AND USE THEREOF

摘要

A shell catalyst for the preparation of vinyl acetate monomer, comprising an oxidic porous catalyst support with an outer shell, containing metallic Pd and Au, wherein the framework structure of the porous catalyst support contains hafnium oxide units. This shell catalyst is suitable for the preparation of VAM and is characterized by a relatively high activity and VAM selectivity and maintains this activity and selectivity over relatively long service lives. Also, processes for the preparation and use of the shell catalyst.