Thiophosphoryl chloride

Thiophosphoryl chloride
Names
IUPAC name
Phosphorothioic trichloride
Other names
Thiophosphoryl chloride
Identifiers
3982-91-0 
ChemSpider 18729 Yes
Jmol-3D images Image
PubChem 19883
Properties
Cl3PS
Molar mass 169.4 g/mol
Appearance Colorless liquid
Density 1.67 g/cm3
Melting point −35 °C (−31 °F; 238 K)
Boiling point 125 °C (257 °F; 398 K)
Reacts
Solubility Soluble in benzene, Chloroform, CS2 and CCl4.
Hazards
MSDS Magnesium chloride MSDS
Main hazards Violent hydrolysis
Except where noted otherwise, data is given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
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Infobox references

Thiophosphoryl chloride is an inorganic compound with the formula PSCl3.[1] It is a colorless liquid with a pungent odor that fumes in moist air. It is synthesized from phosphorus chloride and used to thiophosphorylate organic compounds, such as to produce insecticides.

Synthesis

Thiophosphoryl chloride can be generated by several reactions starting from phosphorus trichloride. The most common and practical synthesis, hence used in industrial manufacturing, is directly reacting phosphorus trichloride with excess sulfur at 180 °C.[2]

PCl3 + S → PSCl3

Using this method, yields can be very high after purification by distillation. Catalysts facilitate the reaction at lower temperatures, but are not usually necessary. Alternatively, it is obtained by combining phosphorus pentasulfide and phosphorus pentachloride.[3]

3 PCl5 + P2S5 → 5 PSCl3

Reactions

PSCl3 is soluble in benzene, carbon tetrachloride, chloroform, and carbon disulfide.[1] However, it hydrolyzes rapidly in basic or hydroxylic solutions, such as alcohols and amines, to produce thiophosphates.[2] In water PSCl3 reacts, and contingent on the reaction conditions, produces either phosphoric acid, hydrogen sulfide, and hydrochloric acid or dichlorothiophosphoric acid and hydrochloric acid.[4]

PSCl3 + 4 H2O → H3PO4 + H2S + 3 HCl
PSCl3 + H2O → HOP(S)Cl2 + HCl

PSCl3 is used to thiophosphorylate, or add P=S, organic compounds.[2] This conversion is widely applicable for amines and alcohols, as well as amino alcohols, diols, and diamines.[1] Industrially, PSCl3 is primarily used to produce insecticides, like parathion.[4]

PSCl3 + 2 C2H5OH → (C2H5O)2PSCl + 2 HCl
(C2H5O)2PSCl + NaOC6H4NO2 → (C2H5O)2PSOC6H4NO2 + NaCl

PSCl3 reacts with tertiary amides to generate thioamides.[1] For example:

C6H5C(O)N(CH3)2 + PSCl3 → C6H5C(S)N(CH3)2 + POCl3

When treated with methylmagnesium iodide, it give tetramethyldiphosphine disulfide ([Me2P(S)].2.[5]

References

  1. 1.0 1.1 1.2 1.3 Spilling, C. D. "Thiophosphoryl Chloride" in Encyclopedia of Reagents for Organic Synthesis John Wiley & Sons, Weinheim, 2001. doi: 10.1002/047084289X.rt104. Article Online Posting Date: April 15, 2001.
  2. 2.0 2.1 2.2 Betterman, G.; Krause, W.; Riess, G.; Hofmann, T. “Phosphorus Compounds, Inorganic” Ullmann’s Encyclopedia of Industrial Chemistry, 2005, Wiley-VCH, Weinheim. doi: 10.1002/14356007.a19_527.
  3. Martin, D. R.; Duvall, W. M. “Phosphorus(V) Sulfochloride” Inorganic Syntheses, 1953, Volume IV, p73. doi: 10.1002/9780470132357.ch24.
  4. 4.0 4.1 Fee, D. C.; Gard, D. R.; Yang, C. “Phosphorus Compounds” Kirk-Othmer Encyclopedia of Chemical Technology. John Wiley & Sons: New York, 2005. doi: 10.1002/0471238961.16081519060505.a01.pub2
  5. G. W. Parshall "Tetramethylbiphosphine Disulfide" Org. Synth. 1965, volume 45, p. 102. doi:10.15227/orgsyn.045.0102