Process for preparing dialkylphosphinate salts

US5973194A · kind A · utility

Assignee

• Clariant Corporation · DE

Inventors

• Norbert Weferling · Hürth, DE
• Hans-Peter Schmitz · Mönchengladbach, DE
• Gunter Kolbe · Kerpen, DE

Key dates

• Filing date: Nov 24, 1998
• Grant date: Oct 26, 1999
• Expiry date: Nov 24, 2018

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C07F9/30
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

Abstract

The invention relates to a process for preparing dialkylphosphinate salts, which comprises PA1 a) reacting elemental yellow phosphorus with alkyl halides in the presence of alkali metal hydroxide or alkaline earth metal hydroxide to form a mixture which comprises as main constituents the salts of alkylphosphonous, phosphorous and hypophosphorous acids, PA1 b) adjusting the mixture to a pH below 7 and then reacting the mixture with olefins in the presence of a free-radical initiator and PA1 c) reacting the dialkylphosphinic acids obtained according to b) and/or alkali metal salts thereof with metal compounds of Mg, Ca, Al, Sb, Sn, Ge, Ti, Zn, Fe, Zr, Ce, Bi, Sr, Mn, Li, Na and/or K to give the metal dialkylphosphinate salts. The invention likewise relates to the use of the metal dialkylphosphinate salts prepared by the process according to the invention to prepare flame retardants.