Pallet and potassium, and cadmium, barium or gold-containing coated catalyst, process for its preparation and its use in the production of vinyl acetate

摘要

The invention relates to Pd/K/Au, Pd/K/Ba and Pd/K/Cd supported catalysts constructed in a shell-shape, their production and their use for the preparation of vinyl acetate from ethylene, acetic acid and oxygen in the gas phase. The said catalysts are produced by impregnating the support particles with a solution of salts of the corresponding elements and then drying them, the dynamic viscosity of the solution being at least 0.003 Pa.s and the solution volume during impregnation being more than 80% of the pore volume of the support particles and the duration of impregnation and the time until the beginning of drying being selected to be short enough so that after drying is completed, a shell of 5% to 80% of the pore volume of the support particles contains the said metal salts.