Phillips Cr/silica catalyst for ethylene polymerization

The Phillips Cr/silica catalyst, discovered by Hogan and Banks at the Phillips Petroleum Company in the early 1950s, is one of the most important industrial catalysts for polyethylene production. In contrast to its great commercial success during the past half-century, academic progress regarding a basic understanding of the nature of the active sites and polymerization mechanisms is lagging far behind. During the last decade, increasing research efforts have been performed on the Phillips catalyst through various approaches, including spectroscopic methods, polymerization kinetics, heterogeneous model catalysts, homogeneous model catalysts, and molecular modeling. Much deeper mechanistic understanding, together with successive catalyst innovations through modifications of the Phillips catalyst, has been achieved.