Patent ID: 7485745

Claim:
A process for preparation of a composition comprising: A) from 98 to 100% by weight of at least one monocarboxy-functionalized dialkylphosphinic ester of the formula (I) wherein 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, Y is methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, phenyl, 2-hydroxyethyl, 2,3-dihydroxypropyl, 2-hydroxypropyl, 3-hydroxypropyl, 4-hydroxybutyl, 3-hydroxybutyl, 2-hydroxybutyl, 6-hydroxyhexyl, allyl, or glycerol, X is H, Li, Na, K or NH 4 , or X is defined as for Y, and then X and Y are two identical radicals or two different radicals of the above organic radicals, 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 7th main group of the periodic table of elements are present and have chemical bonding to carbon or to phosphorus or salts containing halide anions, where the entirety of the components always amounts to 100% by weight, comprising the step of reacting hypophosphorous acid or a salt thereof (component C) of the formula II wherein X is H, Na, K, or NH 4 in the presence of at least one free-radical initiator with at least one α,β-unsaturated carboxylic acid derivative (component D) of the formula III, wherein Z is C 1-18 -alkyl or C 6-18 -aryl or is Y, or with at least one α,β-unsaturated carboxylic acid (component D′) of the formula IV and with at least one olefin (component E) of the formula V wherein R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , and R 7 are defined in the formulae III, IV, and V as in formula I, and wherein when formula IV is used an esterification step with Y—OH follows.