Neues Verfahren zur Synthese von Methacrylsaeureestern

摘要

Methacrylonitrile is prepared from isobutylene by a vapour phase reaction in which a gaseous mixture of isobutylene, oxygen and ammonia is passed over a solid catalyst comprising oxides of molybdenum, and bismuth and one or more of arsenic, antimony and phosphorus, and optionally of an alkali or alkaline earth metal, provided that either an alkali or alkaline earth metal or arsenic or antimony is always present. Catalyst corresponds to the formulae Mo12BiaXbYc, Mo12BiaXbPd and Mo12BiaYcPd where X represents As or Sb, and Y an alkali or alkaline earth metal, and a is 6-12, b 0.5-5, c 0-5 in Mo12BiaXbYc and 1-5 in Mo12BiaYcPd, and d is 0.5 to 5. The catalyst may be on a carrier such as silica or diatomaceous earth and secondary oxygen may be added intermediately.ALSO:Oxidation catalysts comprise the oxides of Mo12BiaXbYc, Mo12BiaXbPd, and Mo12BiaYcPd wherein X represents arsenic or antimony and Y an alkali metal or alkaline earth metal, and a is from 6-12, b from 0,5-5, and d from 0,5-5, and c is from 0-5 in the case of Mo12BiaXbYc but from 1-5 in Mo12BiaYcPd. Examples are oxides of Mo12Bi9CaP, Mo12Bi9As1,5Na2, Mo12Bi9As1,5 and Mo12Bi9Sb2P and the catalyst may be prepared by mixing bismuth nitrate, phosphoric acid, molybdenum oxide, ammonium molybdate, arsenious acid, antimony trioxide, calcium hydroxide, calcium oxide and sodium hydroxide with a carrier such as diatomaceous earth or a silica sol, and calcining (400-550 DEG C.) the resulting mass. Specifications 867,438, 874,593 and 1,000,580 are referred to.