Patent ID: 7128826
Filing Date: 2006-10-31
Classification: C07C,C08F,Y10S

Abstract:
1. In a system for the production of styrene monomer by dehydrogenation of ethylbenzene in an upstream dehydrogenation unit of said system at elevated temperature and in the presence of steam wherein effluent from the dehydrogenation unit is formed that is subsequently separated in a phase separator located downstream from said dehydrogenation unit into a gaseous phase comprising hydrocarbons, an aqueous phase comprising steam condensate, and an organic phase comprising styrene monomer and unreacted ethylbenzene and wherein styrene is then distilled from said organic phase in a distillation unit located downstream from said phase separator, an improved method comprising contacting said effluent with an effective amount of a styrene monomer polymerization inhibitor (SMPI), wherein said SMPI comprises a quinone methide compound having the formula: wherein R 1 and R 2 are independently H, C 1 to C 18 alkyl, C 5 to C 12 cycloalkyl; 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.