PROCESS FOR THE EPOXIDATION OF OLEFINS WITH A FLUORINE-PROMOTED SILVER CATALYST, WHICH SHOWS ENHANCED THERMAL STABILITY UNDER REACTION CONDITIONS

摘要

A process for the preparation of a monoepoxide of an olefin selected from norbornene, norbornadiene and olefins having general formula (I), wherein R1 is hydrogen or alkyl and R2 is an aryl group, a tertiary alkyl group or the group having formula (a) with the proviso that R1 contains no hydrogen atoms in a position allylic to the ethylenic unsaturation, which comprises contacting the olefin with an oxygen-containing gas in the presence of a supported, fluorine-promoted, silver catalyst at epoxide-forming conditions of pressure and temperature, wherein the catalyst consists essentially of a catalyst support material having a surface area of less than 10 square meters per gram having distributed on the surface thereof 0.1 to 50 weight percent silver, 10 to 5000 ppm fluorine, and an amount of cation selected from the group consisting of thallium, alkali metals and alkaline earth metals in the same weight range as the amount of fluorine.