Thiophosphoryl chloride is an inorganic compound with the formula PSCl₃.Spilling, C. D. "Thiophosphoryl Chloride" in Encyclopedia of Reagents for Organic Synthesis John Wiley & Sons, Weinheim, 2001. . Article Online Posting Date: April 15, 2001. It is a colorless pungent smelling liquid that fumes in 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.. :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.Martin, D. R.; Duvall, W. M. “Phosphorus(V) Sulfochloride” Inorganic Syntheses, 1953, Volume IV, p73. . :3 PCl₅ + P₂S₅ → 5 PSCl₃

Structure

Thiophosphoryl chloride has tetrahedral molecular geometry and C_3v molecular symmetry. According to gas electron diffraction, the phosphorus–sulfur bond length is 1.89 Å and the phosphorus–chlorine bond length is 2.01 Å, while the Cl–P–Cl

bond angle Bond or bonds may refer to: Common meanings * Bond (finance), a type of debt security * Bail bond, a commercial third-party guarantor of surety bonds in the United States * Chemical bond, the attraction of atoms, ions or molecules to form chemical ...

is 102°.

Reactions

PSCl₃ is soluble in

benzene Benzene is an organic chemical compound with the molecular formula C6H6. The benzene molecule is composed of six carbon atoms joined in a planar ring with one hydrogen atom attached to each. Because it contains only carbon and hydrogen atoms ...

, carbon tetrachloride, chloroform, and

carbon disulfide Carbon disulfide (also spelled as carbon disulphide) is a neurotoxic, colorless, volatile liquid with the formula and structure . The compound is used frequently as a building block in organic chemistry as well as an industrial and chemical n ...

. However, it hydrolyzes rapidly in basic or hydroxylic solutions, such as alcohols and amines, to produce thiophosphates. In water PSCl₃ reacts, and contingent on the reaction conditions, produces either

phosphoric acid Phosphoric acid (orthophosphoric acid, monophosphoric acid or phosphoric(V) acid) is a colorless, odorless phosphorus-containing solid, and inorganic compound with the chemical formula . It is commonly encountered as an 85% aqueous solution, w ...

, hydrogen sulfide, and

hydrochloric acid Hydrochloric acid, also known as muriatic acid, is an aqueous solution of hydrogen chloride. It is a colorless solution with a distinctive pungent smell. It is classified as a strong acid Acid strength is the tendency of an acid, symbol ...

or dichlorothiophosphoric acid and hydrochloric acid.Fee, D. C.; Gard, D. R.; Yang, C. “Phosphorus Compounds” Kirk-Othmer Encyclopedia of Chemical Technology. John Wiley & Sons: New York, 2005. :PSCl₃ + 4 H₂O → H₃PO₄ + H₂S + 3 HCl :PSCl₃ + H₂O → HOP(S)Cl₂ + HCl PSCl₃ is used to thiophosphorylate (add P=S to) organic compounds. This conversion is widely applicable for amines and alcohols, as well as amino alcohols, diols, and diamines. Industrially, PSCl₃ is used to produce insecticides, like parathion. :PSCl₃ + 2 C₂H₅OH → (C₂H₅O)₂PSCl + 2 HCl :(C₂H₅O)₂PSCl + NaOC₆H₄NO₂ → (C₂H₅O)₂PSOC₆H₄NO₂ + NaCl PSCl₃ reacts with tertiary

amide In organic chemistry, an amide, also known as an organic amide or a carboxamide, is a compound with the general formula , where R, R', and R″ represent organic groups or hydrogen atoms. The amide group is called a peptide bond when it i ...

s to generate thioamides. For example: :C₆H₅C(O)N(CH₃)₂ + PSCl₃ → C₆H₅C(S)N(CH₃)₂ + POCl₃ When treated with

methylmagnesium iodide Methylmagnesium chloride is an organometallic compound with the general formula CH3MgCl. This highly flammable, colorless, and moisture sensitive material is the simplest Grignard reagent and is commercially available, usually as a solution in tet ...

, it give tetramethyldiphosphine disulfide ( e₂P(S)₂. G. W. Parshall "Tetramethylbiphosphine Disulfide" Org. Synth. 1965, volume 45, p. 102.

References

{{reflist Phosphorus halides Thiophosphoryl compounds Thiochlorides