Patent ID: 7838580

Claim:
A salt of alkyl ester of carboxyethyl(alkyl)phosphinic acid, where the salt has the formula (I) R 1 —P(═O)(OX)—CH 2 —CH 2 —CO 2 R 2 wherein R 1 and R 2 wherein R 1 and R 2 are identical or different and, independently of one another, are methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl, n-pentyl or a mixture thereof, and X is Mg, Ca, Zn, Sr; Al, Ce, La; Ge, Sn, Pb, Ti, Zr; Sb, Bi; Cr, Mo, W; Mn; Fe, Co or Ni.