Abstract: A process for making an additive comprising one or more oil-soluble or oil-dispersible molybdenum-sulfur compounds, said process comprising the steps of: (I) reacting in a polar medium a reactant molybdenum compound (A) and a source of a ligand (B), which ligand (B) is capable of rendering the or each molybdenum-sulfur compound oil-soluble or oil-dispersible; and (II) reacting a compound (C), which is capable of reacting with labile sulfur, either with (a) the reaction mixture of step (I) after the reaction of (A) and (B) has begun or (b) the product of step (I). The additive has improved color characteristics and a lubricating oil composition comprising said additive is more benign to corrosion of metals.

Abstract: A process for producing an ammonium polythiomolybdate of the formula (NH4)2Mo3S13.n H2O where n is 0, 1 or 2 in which an aqueous ammoniacal molybdate solution is reacted with hydrogen sulfide gas in a closed system at superatmospheric pressure until the H2S is no longer absorbed by the solution to form a slurry of solid ammonium tetrathiomolybdate containing a portion of the starting molybdenum in a mother liquor containing the balance of the molybdenum and thereafter heat soaking the reaction product in the presence of elemental sulfur to form the desired product.

Abstract: A process for making an additive comprising one or more oil-soluble or oil-dispersible molybdenum-sulfur compounds, said process comprising the steps of: