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.

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

References

  1. ^ International Union of Pure and Applied Chemistry (2014). Nomenclature of Organic Chemistry: IUPAC Recommendations and Preferred Names 2013. The Royal Society of Chemistry. p. 926. doi:10.1039/9781849733069. ISBN 978-0-85404-182-4.
  2. ^ a b c Quin, L. D. A Guide to Organophosphorus Chemistry; Wiley IEEE: New York, 2000; pp 44-69. ISBN 0-471-31824-8
  3. ^ 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.
  4. ^ Lin, Shaoquan; Otsuka, Yasunari; Yin, Liang; Kumagai, Naoya; Shibasaki, Masakatsu (2017). "Catalytic Enantioselective Addition of Diethyl Phosphite to N-Thiophosphinoyl Ketimines: Preparation of (R)-Diethyl (1-Amino-1-phenylethyl)phosphonate". Organic Syntheses. 94: 313–331. doi:10.15227/orgsyn.094.0313.
  5. ^ 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.
  6. ^ 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.
  7. ^ O. Kühl "Phosphorus-31 NMR Spectroscopy" Springer, Berlin, 2008. ISBN 978-3-540-79118-8
Allikas: http://en.wikipedia.org/wiki/Chlorodiphenylphosphine
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