Chlorodiphenylphosphine

Chlorodiphenylphosphine is an organophosphorus compound with the formula (C₆H₅)₂PCl, abbreviated Ph₂PCl. It is a colourless oily liquid with a pungent odor that is often described as being garlic-like and detectable even in the ppb range. It is useful reagent for introducing the Ph₂P group into molecules, which includes many ligands.^[2] Like other halophosphines, Ph₂PCl is reactive with many nucleophiles such as water and easily oxidized even by air.

Chlorodiphenylphosphine

Names
Preferred IUPAC name Diphenylphosphinous chloride[1]
Other names chlorodiphenylphosphine p-chlorodiphenylphosphine diphenyl phosphine chloride diphenylchlorophosphine
Identifiers
CAS Number	1079-66-9 Y
3D model (JSmol)	Interactive image
ChemSpider	59567 Y
ECHA InfoCard	100.012.813
EC Number	214-093-2
PubChem CID	66180
UNII	WO975PJK1Y N
CompTox Dashboard (EPA)	DTXSID7038789
InChI InChI=1S/C12H10ClP/c13-14(11-7-3-1-4-8-11)12-9-5-2-6-10-12/h1-10H Y Key: XGRJZXREYAXTGV-UHFFFAOYSA-N Y InChI=1/C12H10ClP/c13-14(11-7-3-1-4-8-11)12-9-5-2-6-10-12/h1-10H Key: XGRJZXREYAXTGV-UHFFFAOYAM
SMILES ClP(c1ccccc1)c2ccccc2
Properties
Chemical formula	C12H10ClP
Molar mass	220.63776 g mol−1
Appearance	clear to light yellow liquid
Density	1.229 g cm−3
Boiling point	320 ˚C
Solubility in water	Reacts
Solubility	Reacts with alcohols highly soluble in benzene, THF, and ethers
Hazards
GHS labelling:
Pictograms
Signal word	Danger
Hazard statements	H290, H302, H314, H412
Precautionary statements	P234, P260, P264, P270, P273, P280, P301+P312, P301+P330+P331, P303+P361+P353, P304+P340, P305+P351+P338, P310, P321, P330, P363, P390, P404, P405, P501
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). N verify (what is YN ?) Infobox references

Synthesis and reactions

Chlorodiphenylphosphine is produced on a commercial scale from benzene and phosphorus trichloride (PCl₃). Benzene reacts with phosphorus trichloride at extreme temperatures around 600 °C to give dichlorophenylphosphine (PhPCl₂) and HCl. Redistribution of PhPCl₂ in the gas phase at high temperatures results in chlorodiphenylphosphine.^[2][3]

2 PhPCl₂ → Ph₂PCl + PCl₃

Alternatively such compounds are prepared by redistribution reactions starting with triphenylphosphine and phosphorus trichloride.

PCl₃ + 2 PPh₃ → 3 Ph₂PCl

Chlorodiphenylphosphine hydrolyzes to give diphenylphosphine oxide. Reduction with sodium affords tetraphenyldiphosphine:

2 Ph₂PCl + 2 Na → [Ph₂P]₂ + 2 NaCl

With ammonia and elemental sulfur, it converts to the thiophosphorylamide:^[4]

Ph₂PCl + 2 NH₃ + S → Ph₂P(S)NH₂ + NH₄Cl

Uses

Chlorodiphenylphosphine, along with other chlorophosphines, is used in the synthesis of various phosphines. A typical route uses Grignard reagents:^[3]

Ph₂PCl + MgRX → Ph₂PR + MgClX

The phosphines produced from reactions with Ph₂PCl are further developed and used as pesticides (such as EPN), stabilizers for plastics (Sandostab P-EPQ), various halogen compound catalysts, flame retardants (cyclic phosphinocarboxylic anhydride), as well as UV-hardening paint systems (used in dental materials) making Ph₂PCl an important intermediate in the industrial world.^[2][3]

Precursor to diphenylphosphido derivatives

Chlorodiphenylphosphine is used in the synthesis of sodium diphenylphosphide via its reaction with sodium metal in refluxing dioxane.^[5]

Ph₂PCl + 2 Na → Ph₂PNa + NaCl

Diphenylphosphine can be synthesized in the reaction of Ph₂PCl and LiAlH₄, the latter usually used in excess.^[6]

4 Ph₂PCl + LiAlH₄ → 4 Ph₂PH + LiCl + AlCl₃

Both Ph₂PNa and Ph₂PH are also used in the synthesis of organophosphine ligands.

Characterization

The quality of chlorodiphenylphosphine is often checked by 31P NMR spectroscopy.^[7]

Compound	31P chemical shift (ppm vs 85% H3PO4)
PPh3	-6
PPh2Cl	81.5
PPhCl2	165
PCl3	218