Diethyl dithiophosphoric acid explained

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.^[1]

It is prepared by treating phosphorus pentasulfide with ethanol:^[2]

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.^[3]

Diethyl dithiophosphoric acid reacts with zinc oxide to give zinc dithiophosphate, which is used as an oil additive:^[4]

ZnO + 2 (C₂H₅O)₂PS₂H → [(C₂H₅O)₂PS₂]₂Zn + H₂O

See also

• Dimethyl dithiophosphoric acid

Notes and References

1. J. Svara, N. Weferling, T. Hofmann "Phosphorus Compounds, Organic" in Ullmann's Encyclopedia of Industrial Chemistry, Wiley-VCH, Weinheim, 2006.
2. 10.1021/ic50208a046. Oxy and thio phosphorus acid derivatives of tin. 1. Triorganotin(IV) dithiophosphate esters. Inorganic Chemistry. 19. 6. 1662–1670. 1980. Lefferts. J. L.. Molloy. K. C.. Zuckerman. J. J.. Haiduc. I.. Guta. C.. Ruse. D..
3. Okuniewski . Andrzej . Becker . Barbara . 2011 . Ammonium O,O′-diethyl dithiophosphate . Acta Crystallogr. E . 67 . 7 . o1749–o1750 . 10.1107/S1600536811022811 . 21837134 . 3151957 .
4. H. Spikes "The history and mechanisms of ZDDP" Tribology Letters, Vol. 17, No. 3, October 2004. .