Production of 2-phosphonobutane-1,2,4-tricarboxylic acid and the alkali metal salts thereof

US5639909A · kind A · utility

Assignee

• BAYER HEALTHCARE LLC · DE

Inventors

• Christoph Holzner · Neunburg vorm Wald, DE
• Wolfgang Ohlendorf · Leverkusen, DE
• Hans-Dieter Block · Cologne, DE
• Horst Bertram · Neunburg vorm Wald, DE
• Roland Kleinstuck · Bensberg, DE
• Hans-Heinrich Moretto · Cologne, DE

Key dates

• Filing date: May 20, 1996
• Grant date: Jun 17, 1997
• Expiry date: May 20, 2016

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C07F9/4006
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

Abstract

This invention relates to an improved process for the production of 2-phosphono-butane-1,2,4-tricarboxylic acid (PBTC) and the alkali metal salts thereof, in which process dialkyl phosphite, preferably dimethyl or diethyl phosphite, and ethene-1,2-dicarboxylic acid dialkyl ester, in particular the dimethyl or diethyl ester of maleic acid and/or fumaric acid, are initially reacted in the presence of a basic catalyst to yield a phosphonosuccinic acid tetraalkyl ester, the resultant ester is thereupon reacted without further working up with acrylic acid alkyl ester, preferably methyl or ethyl acrylate, in the presence of an alkaline catalyst and the reaction product obtained in this manner is saponified without further working up to yield PBTC or the alkali metal salts thereof. The product when mixed with bleaching lye exhibits reduced chlorine depletion.