Patent ID: 8298440

Claim:
A method for inhibiting the polymerization of vinyl aromatic monomer comprising adding to said monomer an effective polymerization inhibiting amount of a compound comprising (A) a quinone methide derivative having the formula wherein: R 1 and R 2 are independently H, C 4 to C 18 alkyl; C 5 to C 12 cycloaklyl; or C 7 to C 15 phenylalkyl, and R 3 is aryl, or aryl substituted with C 1 to C 6 alkyl, alkoxy, hydroxy, nitro, amino, carboxy, or mixtures thereof; and (B) a phenol compound having the formula wherein R 4 and R 5 may be the same or different and are chosen from C 1 -C 20 alkyl, C 1 -C 30 alkaryl and substituted C 1 -C 30 alkaryl.