Thiophosphoryl chloride is an inorganic compound with the chemical formula PSCl3.[5] 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.
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| Names | |||
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| IUPAC name
Phosphorothioic trichloride
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Other names
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3D model (JSmol)
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| ECHA InfoCard | 100.021.476 | ||
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| UN number | 1837 | ||
CompTox Dashboard (EPA)
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| Properties | |||
| PSCl3 | |||
| Molar mass | 169.38 g·mol−1 | ||
| 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. | ||
| Structure | |||
| Tetrahedral at the P atom | |||
| Hazards | |||
| Occupational safety and health (OHS/OSH): | |||
Main hazards
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Violent hydrolysis; releasing HCl on contact with water,[2] maybe corrosive to metals and skin | ||
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| Danger | |||
| H302, H314, H330 | |||
| P260, P264, P270, P271, P280, P284, P301+P317, P301+P330+P331, P302+P361+P354, P304+P340, P305+P354+P338, P316, P320, P321, P330, P363, P403+P233, P405, P501 | |||
| Flash point | none[3] | ||
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Related compounds
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Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Synthesis
editThiophosphoryl 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.[6]
- 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.[7]
- 3 PCl5 + P2S5 → 5 PSCl3
Structure
editThiophosphoryl chloride has tetrahedral molecular geometry and C3v molecular symmetry, with the structure S=PCl3. According to gas electron diffraction, the phosphorus–sulfur bond length is 189 pm and the phosphorus–chlorine bond length is 201 pm, while the Cl−P−Cl bond angle is 102°.[8]
Reactions
editPSCl3 is soluble in benzene, carbon tetrachloride, chloroform, and carbon disulfide.[5] However, it hydrolyzes rapidly in basic or hydroxylic solutions, such as alcohols and amines, to produce thiophosphates.[6] 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.[9]
- PSCl3 + 4 H2O → H3PO4 + H2S + 3 HCl
- PSCl3 + H2O → HO−P(=S)Cl2 + HCl
An intermediate in this process appears to be tetraphosphorus nonasulfide.[10]
PSCl3 is used to thiophosphorylate organic compounds (to add thiophosphoryl group, P=S, with three free valences at the P atom, to organic compounds).[6] This conversion is widely applicable for amines and alcohols, as well as aminoalcohols, diols, and diamines.[5] Industrially, PSCl3 is used to produce insecticides, like parathion.[9]
- PSCl3 + 2 CH3CH2OH → (CH3CH2−O−)2P(=S)−Cl + 2 HCl
- (CH3CH2−O−)2P(=S)−Cl + Na+[−O−C6H4−NO2] → (CH3CH2−O−)2P(=S)−O−C6H4−NO2 + NaCl
PSCl3 reacts with tertiary amides to generate thioamides.[5] For example:
- C6H5−C(=O)−N(−CH3)2 + PSCl3 → C6H5−C(=S)−N(−CH3)2 + POCl3
When treated with methylmagnesium iodide, it give tetramethyldiphosphine disulfide (H3C−)2P(=S)−P(=S)(−CH3)2.[11]
References
edit- ^ Thiophosphoryl chloride: trade names
- ^ Thiophosphoryl chloride: main hazards
- ^ Thiophosphoryl chloride: flash point
- ^ "Thiophosphoryl chloride". pubchem.ncbi.nlm.nih.gov.
- ^ 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
- ^ a b c Betterman G, Krause W, Riess G, Hofmann T (2005). "Phosphorus Compounds, Inorganic". Ullmann’s Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a19_527. ISBN 3527306730.
- ^ Martin, D. R.; Duvall, W. M. “Phosphorus(V) Sulfochloride” Inorganic Syntheses, 1953, Volume IV, p73. doi:10.1002/9780470132357.ch24.
- ^ Kuchitsu, Kozo; Moritani, Tohei; Morino, Yonezo (1971). "Molecular structures of phosphoryl fluoride, phosphoryl chloride, and thiophosphoryl chloride studied by gas electron diffraction". Inorganic Chemistry. 10 (2): 344–350. doi:10.1021/ic50096a025.
- ^ a b 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
- ^ Almasi, Lucreţia (1971). "The Sulfur–Phosphorus Bond". In Senning, Alexander (ed.). Sulfur in Organic and Inorganic Chemistry. Vol. 1. New York: Marcel Dekker. p. 69. ISBN 0-8247-1615-9. LCCN 70-154612.
- ^ G. W. Parshall "Tetramethylbiphosphine Disulfide" Org. Synth. 1965, volume 45, p. 102. doi:10.15227/orgsyn.045.0102