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.]
