Chemical Properties
Colorless Transparent Liquid
Uses
Triethylphosphine is used as a ligand for arylation. It is used in organic synthesis.
Uses
In organic syntheses.
Definition
ChEBI: Triethylphosphine is a tertiary phosphine.
Safety Profile
Highly flammable liquid. Reactswith oxygen at low temperatures to form an explosiveproduct. When heated to decomposition it emits toxicfumes of POx.
Synthesis
Triethylphosphine is prepared most conveniently by the reaction of excess Grignard reagent on phosphorus trichloride or triphenylphosphite.
3CH3CH2MgBr + PCl3 → (CH3CH2)3P + 3MgBrCl
3CH3CH2MgBr + P(OC6H5)3 → P(CH3CH2)3 + 3C6H5-OMgCl
Purification Methods
All operations should be carried out in an efficient fume cupboard because it is flammable, toxic and has a foul odour. Purify the phosphine by fractional distillation at atmospheric pressure in a stream of dry N2, as it is oxidised by air to the oxide. In 300% excess of CS2 it forms Et3PCS2 (m 118-120o crystallising from MeOH) which decomposes in CCl4 to give Et3PS as a white solid m 94o when recrystallised from EtOH. [Sorettas & Isbell J Org Chem 27 273 1962, Henderson & Streuli J Am Chem Soc 82 5791 1960, pK: Henderson & Streuli J Am Chem Soc 82 5791 1960, see also trimethylphosphine.] Store it in sealed vials under N2. Alternatively, dissolve it in Et2O and shake it with a solution of AgI and KI to form the insoluble complex. Filter off the complex, dry it over P2O5 and the Et3P is regenerated by heating the complex in a tube attached to a vacuum system. [Hewitt & Holliday J Chem Soc 530 1953, Schettas & Isbell J Org Chem 27 2573 1962, Kosolapoff Organophosphorus Compounds, Wiley p 31 1950, Beilstein 4 IV 3431.]
