Diethyl dithiophosphoric acid, sometimes mistakenly called diethyl dithiophosphate, is the organophosphorus compound with the formula (C2H5O)2PS2H. It is the processor for production of the organophosphate insecticide Terbufos. Although samples can appear dark, it is a colorless liquid.J. Svara, N. Weferling, T. Hofmann "Phosphorus Compounds, Organic" in Ullmann's Encyclopedia of Industrial Chemistry, Wiley-VCH, Weinheim, 2006.
It is prepared by treating phosphorus pentasulfide with ethanol: P2S5 + 4 C2H5OH → 2 (C2H5O)2PS2H + H2S
Reactions
Diethyl- and dimethyl dithiophosphoric acids react with bases. The results of this neutralization reaction are salts, e.g., ammonium diethyl dithiophosphate.
Diethyl dithiophosphoric acid reacts with zinc oxide to give zinc dithiophosphate, which is used as an oil additive:H. Spikes "The History and Mechanisms of ZDDP" Tribology Letters, Vol. 17, No. 3, October 2004. .
ZnO + 2 (C2H5O)2PS2H → [(C2H5O)2PS2]2Zn + H2O
Oxidation of dialkoxydithiophosphoric acids with iodine gives the disulfides:
See also Dimethyl dithiophosphoric acid
References