Patent ID: 7410940

Claim:
A method of stabilizing a surfactant comprising a long alkyl or alkenyl chain, comprising adding thereto an effective stabilizing amount of (a 2 ) an antioxidant of the formula in which in the formulae (3) R 1 is hydrogen; C 1 -C 22 alkyl; C 1 -C 22 alkylthio; C 5 -C 12 cycloalkyl; phenyl; or C 7 -C 9 phenylalkyl; R 2 is C 1 -C 22 alkyl; C 5 -C 12 cycloalkyl; phenyl; C 7 -C 9 phenylalkyl; or —SO 3 M; a is 0; 1; or 2; M is hydrogen; alkali metal; or ammonium; and R 4 and R 5 independently of one another are hydrogen; or C 1 -C 22 alkyl wherein the component (a 2 ) is present in a concentration of from 50 to 1000 ppm based on weight of the surfactant.