Chemistry:Thiophosphoryl chloride

Thiophosphoryl chloride

Names
IUPAC name Phosphorothioic trichloride
Other names Phosphoric sulfochloride (1:3) Phosphorus(V) sulfochloride Thiophosphoryl chloride
Identifiers
CAS Number	3982-91-0 Y
3D model (JSmol)	Interactive image
ChemSpider	18729 Y
EC Number	223-622-6
PubChem CID	19883
RTECS number	XN2930000
UNII	II99F8594N Y
UN number	1837
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
SMILES P(=S)(Cl)(Cl)Cl
Properties
Chemical formula	PSCl 3
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)
Solubility in water	Reacts
Solubility	Soluble in benzene, chloroform, CS 2 and CCl 4.
Structure
Molecular shape	Tetrahedral at the P atom
Hazards
Main hazards	Violent hydrolysis; releasing HCl on contact with water, maybe corrosive to metals and skin
GHS pictograms
GHS Signal word	Danger
GHS hazard statements	H302, H314, H330
GHS precautionary statements	P260, P264, P270, P271, P280, P284, P301+317Category:GHS errors, P301+330+331, P302+361+354Category:GHS errors, P304+340, P305+354+338Category:GHS errors, P316Category:GHS errors, P320, P321, P330, P363, P403+233, P405, P501
Flash point	none
Related compounds
Related compounds	Phosphoryl chloride Thiophosphoryl fluoride Thiophosphoryl bromide Thiophosphoryl iodide Phosphorothioic chloride difluoride
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

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Thiophosphoryl chloride is an inorganic compound with the chemical formula PSCl
3. 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.

PCl
3 + S → PSCl
3

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 PCl
5 + P
2S
5 → 5 PSCl
3

Structure

Thiophosphoryl chloride has tetrahedral molecular geometry and C_3v molecular symmetry, with the structure S=PCl
3. 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°.

Reactions

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

PSCl
3 + 4 H
2O → H
3PO
4 + H
2S + 3 HCl

PSCl
3 + H
2O → HO–P(=S)Cl
2 + HCl

PSCl
3 is used to thiophosphorylate organic compounds (to add thiophosphoryl group, P=S, with three free valences at the P atom, to organic compounds). This conversion is widely applicable for amines and alcohols, as well as aminoalcohols, diols, and diamines. Industrially, PSCl
3 is used to produce insecticides, like parathion.

PSCl
3 + 2 CH
3CH
2OH → (CH
3CH
2–O–)
2P(=S)–Cl + 2 HCl

(CH
3CH
2–O–)
2P(=S)–Cl + Na+
[−
O–C
6H
4–NO
2] → (CH
3CH
2–O–)
2P(=S)–O–C
6H
4–NO
2 + NaCl

PSCl
3 reacts with tertiary amides to generate thioamides. For example:

C
6H
5–C(=O)–N(–CH
3)
2 + PSCl
3 → C
6H
5–C(=S)–N(–CH
3)
2 + POCl
3

When treated with methylmagnesium iodide, it give tetramethyldiphosphine disulfide (H
3C–)
2P(=S)–P(=S)(–CH
3)
2.