Process for making alkanephosphonous acid esters

US4549995A · kind A · utility

Assignee

• Hoechst GmbH · DE

Inventors

• Eberhard Auer · Lechenich, DE
• Klaus Gehrmann · Lechenich, DE
• Alexander Ohorodnik · Lechenich, DE
• Johannes Rosenthal · Cologne, DE

Key dates

• Filing date: Nov 23, 1983
• Grant date: Oct 29, 1985
• Expiry date: Nov 23, 2003

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C07F9/48
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

Abstract

The disclosure relates to an improved process for making alkanephosphonous acid esters which comprises: introducing a stoichiometric excess each of an alkyldihalogenophosphane and aliphatic alcohol into a reaction column and reacting them therein at a temperature higher than the boiling point of the reactants but lower than the boiling point of the resulting alkanephosphonous acid ester, this latter being obtained in the base portion of the reaction column and being removed therefrom; continuously expelling overhead of the reaction column a vaporous mixture consisting of by-products formed during the reaction, in the form of hydrogen halide and halide of the aliphatic alcohol, together with aliphatic alcohol in excess, and separating the mixture into its components in a series-connected distilling column, the aliphatic alcohol obtained in the base portion of the distilling column being removed therefrom and recycled into the reaction column, and selectively condensing the mixture issuing overhead with recovery of hydrogen halide gas and liquefied halide of the aliphatic alcohol.