Chlorodiphenylphosphine

Chlorodiphenylphosphine
Preferred IUPAC name Diphenylphosphinous chloride
Other names chlorodiphenylphosphine p-chlorodiphenylphosphine diphenyl phosphine chloride diphenylchlorophosphine
Identifiers
CAS number	1079-66-9 Y
ChemSpider	59567 Y
Jmol-3D images	Image 1
SMILES ClP(c1ccccc1)c2ccccc2
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
Properties
Molecular 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 with water
Y (verify) (what is: Y/N?) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
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 ligand.^[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

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 (EPN or ethyl p-nitrophenyl thionobenzenephosphonate), 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 + AlCl₄

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]

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

References

1. ^ ^{a b c} Quin, L. D. A Guide to Organophosphorus Chemistry; Wiley IEEE: New York, 2000; pp 44-69. ISBN 0471318248
2. ^ ^{a b c} Svara, J.; Weferling, N.; Hofmann, T. "Phosphorus Compounds, Organic," In 'Ullmann's Encyclopedia of Industrial Chemistry, 7th ed.; Wiley-VCH: 2008; doi:10.1002/14356007.a19_545.pub2; Accessed: February 18, 2008.
3. ^ A. Bollmann, K. Blann, J. T. Dixon, F. M. Hess, E. Killian, H. Maumela, D. S. McGuinness, D. H. Morgan, A. Neveling, S. Otto, M. Overett, A. M. Z. Slawin, P. Wasserscheid, S. Kuhlmann, “Ethylene Tetramerization: A New Route to Produce 1-Octene in Exceptionally High Selectivities” J. Am. Chem. Soc. 2004, 126, 14712-14713 plus supporting information. doi: 10.1021/ja045602n
4. ^ Roy, Jackson W; Thomson, RJ; MacKay.m.f, . (1985). "The Stereochemistry of Organometallic Compounds. XXV. The Stereochemistry of Displacements of Secondary Methanesulfonate and p-Toluene-sulfonate esters by Diphenylphosphide Ions. X-ray Crystal Structure of (5α-Cholestan-3α-yl)diphenylphosphine Oxide". Australian Journal of Chemistry 38 (1): 111–18. doi:10.1071/CH9850111. 
5. ^ Stepanova, Valeria A.; Dunina, Valery V.; Smoliakova, Irina P. (2009). "Reactions of Cyclopalladated Complexes with Lithium Diphenylphosphide". Organometallics 28 (22): 6546–6558. doi:10.1021/om9005615. 
6. ^ O. Kühl "Phosphorus-31 NMR Spectroscopy" Springer, Berlin, 2008. ISBN 978-3-540-79118-8