Patent ID: 8394747

Claim:
A method for preventing metal ion catalyzed oxidation and polymerization reactions in a hydrocarbon medium comprising sequestering the metal ion by the addition of an effective amount of a Mannich condensation product prepared by the Mannich condensation of: (a) a polyisobutyl-substituted hydroxyaromatic compound, wherein the polyisobutyl group is derived from polyisobutene containing at least 70 weight percent methylvinylidene isomer and has a number average molecular Weight in the range of from about 400 to about 2500; (b) an aldehyde: (c) an amino acid or ester derivative thereof, and (d) an alkali metal base wherein the amino acid or ester derivative thereof is represented by the following formula: wherein W is —[CHR″]— m wherein each R″ is independently H, alkyl having one carbon atom to about 15 carbon atoms, or a substituted-alkyl having one carbon atom to about 10 carbon atoms and one or more substituents selected from the group consisting of amino, amido, benzyl, carboxyl, hydroxyl, hydroxyphenyl, imidazolyl, imino, phenyl, sulfide, or thiol; and m is an integer from one to 4, and A is hydrogen or alkyl having one carbon atom to about 6 carbon atoms.