Thiophosphoryl chloride

Thiophosphoryl chloride
IUPAC name Phosphorothioic trichloride
Other names Thiophosphoryl chloride
Identifiers
CAS number	3982-91-0
PubChem	19883
ChemSpider	18729 Y
Jmol-3D images	Image 1
SMILES P(=S)(Cl)(Cl)Cl
InChI InChI=1S/Cl3PS/c1-4(2,3)5 Y Key: WQYSXVGEZYESBR-UHFFFAOYSA-N Y InChI=1/Cl3PS/c1-4(2,3)5 Key: WQYSXVGEZYESBR-UHFFFAOYAE
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
Y chloride (verify) (what is: Y/N?) 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.