Oxide-Supported Titanium Catalysts: Structure–Activity Relationship in Heterogeneous Catalysis, with the Choice of Support as a Key Step

The reactions of tetrakis­(neopentyl)­titanium, TiNp4 (1), with the surface of three solid oxides, silica, silica–alumina, and alumina, all partially dehydroxylated at 500 °C under vacuum were achieved. The resulting supported organometallic species react with dihydrogen to form the corresponding supported hydrides. The preparation of supported titanium hydrides on alumina is described here in detail, and the species obtained were extensively characterized by FTIR, solid-state NMR and EPR spectroscopy, and mass-balance analysis. The supported titanium hydride species were tested in three important reactions for petrochemistry: epoxidation of 1-octene, depolymerization of Fischer–Tropsch waxes, and polymerization of ethylene. The activities of titanium hydrides supported on alumina were compared to those of their silica- and silica–alumina-supported analogues.