What Is Triphenyl Phosphite?
Triphenyl phosphite is an organophosphorus compound consisting of three phenyl groups bonded to a phosphorus atom.
Among the various existing manufacturing processes, the Friedel-Crafts reaction of benzene and phosphorus trichloride is used industrially. In the Friedel-Crafts reaction, an alkyl or acyl group is substituted for an aromatic compound.
Uses of Triphenyl Phosphite
Triphenyl phosphite is used in a wide variety of chemical reactions, most of which involve organic compounds.
Examples of chemical reactions using triphenyl phosphite include the Appel reaction and the Wittig reaction. Other examples include the Staudinger reaction, the Mitsunobu reaction, and the Heck reaction.
Properties of Triphenyl Phosphite
At room temperature, triphenyl phosphite is a crystalline white solid. It has a melting point of 80°C, a boiling point of 377°C, a density of 1.1 g/cm3, and a flash point of 180°C. It is relatively stable in air and soluble in non-polar organic solvents.
Its chemical formula is C18H15P with a molar mass of 262.29 g/mol, and it is sometimes called triphenylphosphane. The molecule has a triangular pyramidal shape.
Other Information on Triphenyl Phosphite
1. Reaction of Triphenyl Phosphite
Triphenyl phosphite reacts with alkyl halides (R-X) to give phosphonium salts. Phosphonium salts can react with strong bases to yield ylides.
The Staudinger reaction of triphenyl phosphite with azide gives rise to nitrogen, which forms a P=N bond; compounds with a P=N bond liberate an amine when reacted with water and an imine when reacted with carbonyl compounds.
2. Organic Chemical Reactions Using Triphenyl Phosphite
In organic chemistry, triphenyl phosphite is used in various reactions. For example, the Appel reaction using triphenyl phosphite and carbon tetrachloride can alkylate almost all alcohols.
It is also used as a raw material for Wittig reagents. Today, the Wittig reaction is being used to develop various pharmaceuticals, particularly antibiotics.
In the Mitsunobu reaction, triphenyl phosphite can be used together with diethyl azodicarboxylate (DEAD) as a dehydration-condensation reaction.
3. Triphenyl Phosphite as a Precursor for Organophosphorus Compounds
Triphenyl phosphite is generally used as a precursor to organophosphorus compounds. Alkali metal diphenylphosphides can be obtained from triphenyl phosphite by reaction with alkali metals.
Alkali metal diphenylphosphides react with alkyl halides (R-X) to form RPh2P. Thus, diverse phosphine ligands can be synthesized, including methyl diphenylphosphine (MePh2P).
A similar reaction with alkyl dihalides yields bis(diphenylphosphino)alkanes. Specifically, the reaction of 1,2-dibromoethane with alkali metal diphenylphosphides yields 1,2-bis(diphenylphosphino)ethane.
On the other hand, a weaker acid such as ammonium chloride can be used to obtain diphenylphosphine from alkali metal diphenylphosphide.