Abstract: Ammonia compounds improve zinc dihydrocarbyl dithiophosphate compositions and processes for their preparation.

Abstract: Processes for the manufacture of substantially haze free zinc salts of dihydrocarbyldithiophosphoric acid comprising the addition of an effective amount of a surface active agent or surfactant at or prior to the neutralization of a dihydrocarbyldithiophosphoric acid by zinc oxide that reduces the Electrophoretic mobility (EM) of an untreated colloidal zinc oxide particle by about 25%. Generally the mobility of the treated colloidal zinc compound particle is reduced to less than about 1.0 .times.10.sup.-3 microns/sec. per volt/cm.

Abstract: Disclosed are a process for manufacturing metal diaryl dithiophosphates, certain metal diaryl dithiophosphates, and lubricating oil compositions containing said metal diaryl dithiophosphates. The process for the manufacture of metal diaryl dithiophosphate generally comprises reacting P.sub.2 S.sub.5 with a hydroxyl aryl compound to form a dithiophosphoric acid; and neutralizing said dithiophosphoric acid with zinc, barium, cadmium, magnesium or nickel base in the presence of an effective amount of a promoter, said promoter comprising dialkyl dithiophosphoric acid. Metal diaryl dithiophosphates, especially for use in lubricating oil compositions, can be made by the above process.