Process for making phosphonic acid dichlorides

US4735748A · kind A · utility

Assignee

• Hoechst GmbH · DE

Inventor

• Werner Pieper · Kerpen, DE

Key dates

• Filing date: Nov 13, 1986
• Grant date: Apr 5, 1988
• Expiry date: Nov 13, 2006

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C07F9/42
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

Abstract

Phosphonic acid dichlorides of the general formula I ##STR1## are made by reacting thionyl chloride with a phosphonic acid dialkylester of the general formula II ##STR2## and using, as the catalyst, a compound of the general formulae III, IV or V EQU R.sup.1 R.sup.2 R.sup.3 R.sup.4 PX (III) EQU R.sup.1 R.sup.2 R.sup.3 P (IV) EQU R.sup.1 R.sup.2 R.sup.3 PO (V) in which R.sup.1, R.sup.2 and R.sup.3 each stand for identical or different alkyl groups or aryl groups having from 1 to 8 carbon atoms, X stands for chlorine or bromine, R.sup.4 has the same meaning as R.sup.1 through R.sup.3 or stands for chlorine or bromine.