Patent ID: 6222080
Filing Date: 2001-04-24
Classification: C07C

Abstract:
A method of inhibiting polymerization of a vinyl aromatic compound during distillation comprising:(i) providing a vinyl aromatic compound;(ii) forming a mixture by adding to the vinyl aromatic compound an effective amount of a polymerization inhibitor which comprises an N-phenyl-1,4-benzoquinoneimine compound having the formula: ##STR6##wherein R is NR.sup.1 R.sup.2 wherein R.sup.1 and R.sup.2 are independently selected from the group consisting of hydrogen, C.sub.1 -C.sub.8 alkyl, C.sub.6 -C.sub.10 aryl, C.sub.7 -C.sub.16 alkaryl and C.sub.3 -C.sub.8 cycloalkyl; OR.sup.3 wherein R.sup.3 is hydrogen, C.sub.4 -C.sub.8 cycloalkyl or C.sub.1 -C.sub.8 alkyl; and R.sup.4 and R.sup.5 are independently selected from the group consisting of hydrogen, C.sub.1 -C.sub.8 alkyl, C.sub.4 -C.sub.8 cycloalkyl, C.sub.6 -C.sub.10 aryl and C.sub.7 -C.sub.16 alkaryl; and(iii) distilling the mixture.