Chemical Properties
Colorless liquid; characteristic odor. Miscible with most common
organic solvents; insoluble in water; hydrolyzes
slowly in water; exposure to air should be minimum;
high thermal stability. Combustible.
Uses
Triisopropyl phosphite can be used as a reactant:
- With Ru-based indenylidene complexes to form 1st generation complexes for metathesis reactions.
- In Perkow-type reaction to synthesize compounds containing polarized carbon-carbon double bonds.
- For the synthesis of phosphonohydrazines by reacting with arylamines and isoamyl nitrite.
It can also be used as an alternative to triphenylphosphine in Mitsunobu reaction to facilitate the isolation of products.
Uses
Intermediate for insecticides, component of
vinyl stabilizers, lubricant additive, specialty solvent.
Synthesis
A solution of 180.3 g (3 mol) of anhydrous isopropyl alcohol and 447 g (477 ml, 3 mol) of freshly distilled diethylaniline in 1 l of dry petroleum ether (b.p. 40–60°) is placed in a 3-l three-necked flask fitted with a sealed stirrer, an efficient reflux condenser, and a 500-ml dropping funnel, which is charged with a solution of 137.5 g (87.5 ml, 1 mol) of freshly distilled phosphorus trichloride in 400 ml of dry petroleum ether (b.p. 40–60°). The flask is cooled in a cold-water bath. With vigorous stirring, the phosphorus trichloride solution is introduced at such a rate that the mixture boils gently towards the end of the addition. After the addition, which requires about 30 minutes, the mixture is heated under gentle reflux for about 1 hour with stirring. The suspension, containing a copious precipitate of diethylaniline hydrochloride, is then cooled and filtered with suction through a sintered glass funnel. The cake of the amine salt is well compressed and washed with five 100-ml. portions of dry petroleum ether (b.p. 40–60°). The filtrate and washings are combined and concentrated by distillation at water-bath temperature through a 75-cm. Vigreux column. The residue is transferred to a pear-shaped flask and distilled under a water-pump vacuum through a 75-cm. Vigreux column. After a small fore-run, the product Triisopropyl phosphite is collected. It has the following properties: b.p. 43.5°/1.0 mm; nD25 1.4080; d417 0.917.
Purification Methods
Distil it from sodium, under vacuum, through a column packed with glass helices. (This removes any dialkyl phosphonate.) [Ford-Moore & Williams J Chem Soc 1465 1947, Arbuzov Chem Ber 38 1171 1905, see Verkade & Coskren in Organo Phosphorus Compound (Kosolapoff & Maier eds) Wiley Vol 2 pp 1-187 1972, Beilstein 1 IV 1476.]
