Oxymolybdenum dialkyldithiophosphates and lubricants containing same

A process of forming a molybdenum-containing compound comprising treating an ammonium or alkali metal molybdate with more than the stoichiometric amount of a concentrated hydrohalic acid required to simply acidify the molybdate salts, at a temperature ranging from ambient to 80.degree. C.;

• then, adding not more than two moles of dialkyl phosphorodithioic acid for each mole of molybdenum in the molybdate reactant;
• refluxing the reaction mixture and removing the water of reaction azeotropically.

A composition comprising a lubricating oil or grease containing as an additive with antiwear and extreme pressure properties a compound of the formula:

• [(RO).sub.2 PS.sub.2 ].sub.2 Mo.sub.2 O.sub.4
• where R is a hydrocarbyl radical having from 1 to 30 carbon atoms.

A molybdenum-containing compound prepared by the process comprising treating an ammonium or alkali metal molybdate with more than the stoichiometric amount of a concentrated hydrohalic acid required to simply acidity said molybdate at a temperature ranging from ambient to 80.degree. C.;

• then adding not more than two moles of dialkyl phosphorodithioic acid for each mole of molybdenum in said molybdate reactant;
• refluxing the reaction mixture and removing the water of reaction.