SULFIDE POISONING OF ETHYLENE POLYMERIZATION OVER PHILLIPS CR/SILICA CATALYST

Ethylene polymerization over the Phillips Cr/silica catalyst is strongly inhibited by alcohols, organic amines and sulfides. In this study poisoning experiments were carried out with n-butyl mercaptan and diethyl sulfide. Although the maximum polymerization rate was decreased by these poisons, the main inhibition came from an extension of the induction time. Activity developed very sluggishly in the presence of sulfide. This indicates the initiation reaction (reduction or alkylation) is inhibited more strongly than polymerization itself. Therefore caution is warranted when active site concentrations are determined from poisoning experiments.