Chlorodiphenylphosphine

Chlorodiphenylphosphine

Names
Preferred IUPAC name Diphenylphosphinous chloride
Other names chlorodiphenylphosphine p-chlorodiphenylphosphine diphenyl phosphine chloride diphenylchlorophosphine
Identifiers
CAS Number	1079-66-9 Y
3D model (Jmol)	Interactive image
ChemSpider	59567 Y
ECHA InfoCard	100.012.813
UNII	WO975PJK1Y Y
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
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Y verify (what is YN ?)
Infobox references

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.^[1] Like other halophosphines, Ph₂PCl is reactive with many nucleophiles such as water and easily oxidized even by air.

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). Redistribution of PhPCl₂ in the gas phase at high temperatures results in chlorodiphenylphosphine.^[1][2]

2 PhPCl₂ → Ph₂PCl + PCl₃

Alternatively such compounds are prepared by redistribution reactions starting with triphenylphosphine and phosphorus trichloride. Synthesis of Ph₂PCl by the direct reaction of phenylmagnesium bromide and phosphorus trichloride is not practiced. On the other hand, PCl₃ can be usefully converted to its monoamide, which in turn undergoes alkylation or arylation. Subsequent removal of the amide gives :^[3]

PCl₃ + 2 (iPr)₂NH → (iPr)₂NH₂Cl + (iPr)₂NPCl₂

(iPr)₂NPCl₂ + 2 PhMgBr → (iPr)₂NPPh₂ + 2 MgBrCl

(iPr)₂NPPh₂ + 2 HCl → (iPr)₂NH₂Cl + PPh₂Cl

Unlike the synthesis of chlorodiisopropylphosphine, reaction of two equivalents of the phenyl Grignard reagents with PCl₃ does not efficiently afford the monochloride.

Chlorodiphenylphosphine hydrolyzes to give diphenylphosphine oxide. With amines, it forms the amides Ph₂PNR₂.

Uses

Ph₂PCl, along with other chlorophosphines, is used in the synthesis of various phosphines. A typical route uses Grignard reagents:^[2]

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.^[1][2]

Precursor to diphenylphosphido derivatives

Chlorodiphenylphosphine is used in the synthesis of sodium diphenylphosphide via its reaction with sodium metal in refluxing dioxane.^[4]

Ph₂PCl + 2 Na → Ph₂PNa + NaCl

Diphenylphosphine can be synthesized in the reaction of Ph₂PCl and LiAlH₄, the latter usually used in excess.^[5]

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.^[6]

References