申请人:Istituto Guido Donegani S.p.A.
公开号:US04701550A1
公开(公告)日:1987-10-20
There is described a process for preparing alkyl esters of methyltartronic acid by hydroxylation of methacrylic acid to alpha-methylglyceric acid with H.sub.2 O.sub.2, in an aqueous medium, in the presence of H.sub.2 WO.sub.4 and optionally of H.sub.3 PO.sub.4 or H.sub.3 AsO.sub.4 or alkaline salts thereof as catalysts, at pH<2 and at temperatures of from 50.degree. to 100.degree. C., by subsequent oxidation of alpha-methylglyceric acid to methyltartronic acid with HNO.sub.3 in excess or with O.sub.2, in an aqueous-alkaline medium, in the presence of Pd or Pt carried on carbon or oxides thereof as catalysts, at temperatures of 60.degree.-100.degree. C., and final esterification of methyltartronic acid with alcohols C.sub.1 -C.sub.4.
描述了一种制备甲基酒石酸酯的过程,通过将甲基丙烯酸在水性介质中与H.sub.2 O.sub.2反应羟基化成α-甲基甘油酸,存在H.sub.2 WO.sub.4和可选的H.sub.3 PO.sub.4或H.sub.3 AsO.sub.4或它们的碱性盐作为催化剂,pH<2,温度在50度到100度之间,随后将α-甲基甘油酸氧化成甲基酒石酸,使用过量的HNO.sub.3或O.sub.2,在水性碱性介质中,在Pd或Pt负载的碳或氧化物存在下作为催化剂,温度在60度到100度之间,最后将甲基酒石酸与C.sub.1 -C.sub.4醇发生酯化反应。