Diethyl dithiophosphoric acid

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]

Diethyl dithiophosphoric acid

Names
Preferred IUPAC name O,O-Diethyl hydrogen phosphorodithioate
Other names O,O-Diethyl dithiophosphoric acid; Diethyl dithiophosphate; Diethyl phosphorodithioate; Diethyl ester of phosphorodithioic acid
Identifiers
CAS Number	298-06-6 Y
3D model (JSmol)	Interactive image
ChEMBL	ChEMBL1886492
ChemSpider	8917
ECHA InfoCard	100.005.506
EC Number	206-055-9
PubChem CID	9274
RTECS number	TD7350000
UNII	02C5XR639P Y
CompTox Dashboard (EPA)	DTXSID6027133
InChI InChI=1S/C4H11O2PS2/c1-3-5-7(8,9)6-4-2/h3-4H2,1-2H3,(H,8,9) Key: IRDLUHRVLVEUHA-UHFFFAOYSA-N InChI=1/C4H11O2PS2/c1-3-5-7(8,9)6-4-2/h3-4H2,1-2H3,(H,8,9) Key: IRDLUHRVLVEUHA-UHFFFAOYAW
SMILES CCOP(=S)(OCC)S
Properties
Chemical formula	C4H11O2PS2
Molar mass	186.22 g·mol−1
Appearance	colorless liquid
Melting point	< 0 °C (32 °F; 273 K)
Boiling point	66 °C (151 °F; 339 K) at 1 mmHg
Hazards
GHS labelling:
Pictograms
Signal word	Danger
Hazard statements	H301, H311, H314, H330
Precautionary statements	P260, P264, P270, P271, P280, P284, P301+P310, P301+P330+P331, P302+P352, P303+P361+P353, P304+P340, P305+P351+P338, P310, P312, P320, P321, P322, P330, P361, P363, P403+P233, P405, P501
NFPA 704 (fire diamond)	3 2 1
Flash point	82 °C (180 °F; 355 K)
Autoignition temperature	538 °C (1,000 °F; 811 K)
Lethal dose or concentration (LD, LC):
LD50 (median dose)	500 mg/kg (rabbit, dermal) 4510 mg/kg (rat, oral)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

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

P₂S₅ + 4 C₂H₅OH → 2 (C₂H₅O)₂PS₂H + H₂S

Reactions

Zinc dithiophosphate.

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

Oxidation of dialkoxydithiophosphoric acids with iodine gives the disulfides:^[5]

2 (RO)₂PS₂H + I₂ → (RO)₂P(S)S−SP(S)(OR)₂ + 2 HI

See also

• Dimethyl dithiophosphoric acid