catalyst, modified silica support for a catalyst, methods of producing a modified silica support, catalyst and ethylenically unsaturated ester or carboxylic acid, and process for preparing an ethylenically unsaturated ester or acid

摘要

a catalyst has a modified silica support and comprises a modifying metal, zirconium and / or hafnium, and a catalytic metal on the modified support. the catalyst has at least a proportion, typically at least 25% of modifying metal present in portions having a total of up to 2 modifying metal atoms. the portions can be derived from a source of monomeric and / or dimeric cations. a production method: - provides a silica support with isolated silanol groups with optional treatment to provide isolated silanol groups (-sioh) at a level of 2.5 groups per nm2; contacting the silica support, optionally treated, with a modifying metal compound zirconium or monomeric hafnium to perform the adsorption on the support; optionally calcines the modified support for a time and at a temperature sufficient to convert the zirconium or monomeric hafnium compound adsorbed on the surface to a zirconium or hafnium oxide or hydroxide in preparation for catalyst impregnation. a method of producing an ethylenically unsaturated ester or carboxylic acid, typically α, ß-ethylenically unsaturated ester or carboxylic acid, comprising the steps of contacting formaldehyde or a suitable source thereof with an ester or carboxylic acid in the presence of catalyst and optionally in the presence of an alcohol, in which said catalyst is used.