Preparation of catalysts for producing methacrolein and methaycrylic acid.

摘要

A method for preparing a multicomponent catalyst comprising molybdenum, bismuth, iron and cesium or thallium for producing methacrolein and methacrylic acid by the gas-phase catalytic oxidation of isobutylene or tert-butanol with molecular oxygen, wherein a slurry comprising ammonium molybdate which is a material for the molybdenum component as well as materials for the bismuth, iron and cesium or thallium components is used; at least one of materials for components other than molybdenum is dissolved in an aqueous solution containing 0.01 to 0.36 mole of nitric acid per 1 mole of ammonium molybdate; and said nitric acid excludes nitric acid radicals contained in the materials for the catalyst. According to the present invention, the amount of nitric acid used is controlled in a particular range, so that a highly active catalyst for gas-phase catalytic oxidation is obtained.