Hydroconversion process using a sulfided molybdenum catalyst concentrate

A process for converting a heavy hydrocarbonaceous chargestock to lower boiling products which process comprises reacting said hydrocarbonaceous chargestock in the presence of hydrogen, at hydroconversion conditions, which include a hydrogen partial pressure from about 50 to 5000 psig and a temperature from about 650.degree. to 900.degree. F., in the presence of a catalyst concentrate having been prepared by the steps comprising:

• (a) forming a precursor concentrate by mixing:
• (i) a hydrocarbonaceous oil comprising constituents boiling above about 1050.degree. F.;
• (ii) a metal compound, said metal being selected from the group consisting of Groups IVB, VB, VIB, VIIB, and VIII, of the Periodic Table of the Elements, in an amount to provide from about 0.2 to 2 wt. % metal, based on said hydrocarbonaceous oil;
• and
• (b) heating the concentrate, in the substantial absence of added hydrogen, at a temperature from about 530.degree. F. to about 800.degree. F., and a total pressure of from about 0 psig to about 500 psig, for a time sufficient to convert said catalyst precursor to a solid molybdenum-containing catalyst,
• wherein a sulfiding agent consisting essentially of elemental sulfur is used at any stage of the catalyst preparation in an amount so that the atomic ratio of elemental sulfur to metal is about 1/1 to 8/1.