Zinc Dithiophosphate

Zinc Dithiophosphate

Zinc dialkyldithiophosphates (often referred to as ZDDP) are a family of coordination compounds invented by Castrol that feature zinc bound to the anion of dithiophosphoric acid. These uncharged compounds are not salts. They are soluble in nonpolar solvents, and the longer chain derivatives easily dissolve in mineral and synthetic oils used as lubricants. They come under CAS number . In aftermarket oil additives, the percentage of ZDDP ranges approximately between 2-15%.

The alkyl groups can be branched and linear alkanes between 1-14 carbons length, 2-butyl, pentyl, hexyl, 1,3-dimethylbutyl, heptyl, octyl, isooctyl (2-ethylhexyl), 6-methylheptyl, 1-methylpropyl, dodecylphenyl, and others. A mix of zinc dialkyl(C3-C6)dithiophosphates come under CAS number . List of other examples with their CAS numbers is here.