Thiophosphoryl chloride

Thiophosphoryl chloride
IUPAC name

Phosphorothioic trichloride
Other names

Thiophosphoryl chloride
Identifiers
CAS number 3982-91-0 Y
PubChem 19883
ChemSpider 18729 Y
Jmol-3D images Image 1
Properties
Molecular formula Cl3PS
Molar mass 169.4 g/mol
Appearance Colorless liquid
Density 1.67 g/cm3
Melting point

−35 °C (987 K)
Boiling point

125 °C (1685 K)
Solubility in water Reacts
Solubility Soluble in benzene, Chloroform, CS2 and CCl4.
Hazards
MSDS Magnesium chloride MSDS
Main hazards Violent hydrolysis
Flash point  ?°C
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Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

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

Synthesis

Thiophosporyl 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 can further the reaction at lower temperatures, but are not necessary. Alternatively, the reaction of phosphorus pentasulfide and phosphorus pentachloride also affords thiophosporyl chloride in yields around 70%. [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]

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

References

  1. ^ a b c d 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. ^ a b c Betterman, G.; Krause, W.; Riess, G.; Hofmann, T. “Phosphorus Compounds, Inorganic” Ullman’s Encyclopedia of Industrial Chemistry. John Wiley & Sons: New York, 2005. doi: 10.1002/14356007.a19_527.
  3. ^ Martin, D. R.; Duvall, W. M. “Phosphorus (V) Sulfochloride” Inorganic Syntheses, Volume IV. McGraw-Hill, 1953. doi: 10.1002/9780470132357.ch24.
  4. ^ 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.