Catalysts from molybdenum polysulfide precursors, their preparation and

Abstract

A process for the preparation of novel highly active, highly selective hydrotreating catalysts. These catalysts are prepared, in bulk or in supported form, from a catalyst precursor characterized by the formula B.sub.x [Mo.sub.3 S.sub.z ] where B is an ammonium ion, polyammonium ion, tertiary or quaternary phosphonium ion, or a hydrocarbyl substituted ammonium ion, hydrocarbyl substituted polyammonium ion, or hydrocarbyl substituted tertiary or quaternary phosphonium ion, x is 1 where B is a divalent cationic moiety, or 2 where B is a monovalent cationic moiety, [Mo.sub.3 S.sub.z ] is a divalent anionic moiety wherein z is an integer greater than 15. The catalyst precursor is dispersed in an ammonium sulfide or dilute ammonium polysulfide solution and heated to remove sulfur from said catalyst precursor to provide a z value of 15 or less. Carbon is also removed from the catalyst precursor and, where B of the B.sub.x [Mo.sub.3 S.sub.z ] catalyst precursor is a non-carbon containing moiety, the finished catalyst will contain an atomic ratio of C/Mo of less than about 0.05. Decomposition of the catalyst precursor in the presence of hydrogen, hydrocarbon and sulfur forms the highly active hydrotreating catalyst.