PROCESS FOR PRODUCTION OF A SILICA-SUPPORTED ALKALI METAL CATALYST

摘要

A process for regenerating a silica-supported depleted alkali metal catalyst is described. The level of alkali metal on the depleted catalyst is at least 0.5 mol % and the silica support is a zero-gel. The process comprises the steps of contacting the silica supported depleted alkali metal catalyst with a solution of a salt of the alkali metal in a solvent system that has a polar organic solvent as the majority component. A re-impregnated catalyst prepared by the process of the invention any comprising a silica zero-gel support and a catalytic metal selected from an alkali metal in the range 0.5-5 mol % on the catalyst, wherein the surface area of the silica support is <180 m2/g is also described. The invention is applicable to a process for preparing an ethylenically unsaturated acid or ester comprising contacting an alkanoic acid or ester of the formula R1—CH2—COOR3, with formaldehyde or a suitable source of formaldehyde.

主权项

1. A process for preparing an ethylenically unsaturated acid or ester comprising: contacting an alkanoic acid or ester of the formula R1—CH2—COOR3, with formaldehyde or a suitable source of formaldehyde of formula I as defined below: where R5 is methyl and R6 is H; X is O; n is 1; and m is 1; in the presence of a re-impregnated catalyst, and optionally in the presence of an alkanol; wherein R1 is hydrogen or an alkyl group with 1 to 12 carbon atoms and R3 is independently, hydrogen or an alkyl group with 1 to 12 carbon atoms, wherein the re-impregnated catalyst comprises a silica zero-gel support having a surface area of <180 m2/g, and a catalytic metal selected from an alkali metal ranging from 0.5 to 5 mol % on the re-impregnated catalyst.