| abstract |
A method for inhibiting the polymerization of vinyl aromatic monomers, which comprises adding to said monomers an effective polymerization inhibitory amount of a composition comprising (A) a quinomethane derivative having the formula in which: R1 and R2 are independently alkyl C4 to C18; C5 to C12 cycloalkyl; or C7 to C15 phenyl-alkyl, and R3 is aryl, or aryl substituted with C1 to C6 alkyl, alkoxy, hydroxy, nitro, amino, carboxy or mixtures thereof; and (B) a hydroxylamine compound having the formula in which R 10 and R 11 are the same or different and are hydrogen, alkyl, aryl, alkaryl, aralkyl or hydroxyalkyl groups, and preferably have about three to about twenty atoms carbon |