Patent ID: 8097753

Claim:
A process for preparation of a composition comprising: A) from 98 to 100% by weight of at least one monocarboxy-functionalized dialkylphosphinic acid of the formula (I) in which R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , and R 7 are identical or different and, independently of one another, are H, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, or phenyl, X and Y are identical or different and, independently of one another, are H, Li, Na, K, or NH 4 , and B) from 0 to 2% by weight of at least one halogen, wherein the at least one halogen is a chemical compound in which atoms of the 7 th main group are present, chemically bonded to carbon or phosphorus, or are salts containing halide anions, where the entirety of the components always amounts to 100% by weight, comprising the steps of reacting component C, of the formula II wherein X is H, Na, K, or NH 4 with a ketone to give 1-hydroxy-1-dialkylphosphinate, reacting the 1-hydroxy-1-dialkylphosphinate, in the presence of a free-radical initiator with component E of the formula IV wherein R 1 , R 2 , R 3 , and R 4 are defined as in formula I, removing the ketone, and reacting the resultant reaction mixture, in the presence of a free-radical initiator with component D, wherein component D is a α,β-unsaturated carboxylic acid of the formula III, wherein R 5 , R 6 , and R 7 are defined as in formula I and Z is H, C 1-18 -alkyl, or C 6-18 -aryl, or is Y.