A
2-l. round-bottomed flask containing
284 g. (113 ml., 2 moles) of methyl iodide2 is fitted with an
efficient water-cooled condenser and a
dropping funnel which is charged with
416 g. (453 ml., 2 moles) of triisopropyl phosphite (Note
1). A few pieces of porous plate are added to the
methyl iodide, and about
50 ml. of the phosphite is introduced. The mixture is heated over a gauze with a free flame until an exothermic reaction begins. The flame is then withdrawn and the remainder of the phosphite is added at such a rate that the mixture keeps boiling briskly. Towards the end of the addition it may be necessary to reapply heat. After the addition is complete, the mixture is boiled under reflux for 1 hour. The condenser is replaced by a
50–75 cm. Vigreux column attached to a
condenser set for distillation, and the bulk of the
isopropyl iodide is distilled at
85–95° (atmospheric pressure). The residue is transferred to a
pear-shaped flask for distillation through a 75-cm. Vigreux column under reduced pressure. The remainder of the
isopropyl iodide is distilled at water-pump pressure, a
Dry Ice trap being interposed between the
receiver and the pump in order to effect complete condensation. A total of
310 g. (
91%) of
isopropyl iodide is thus recovered. The residue is then fractionated at vacuum-pump pressure. Except for a small fore-run and residue, the product distils almost entirely at
51°/1.0 mm. (
46°/0.8 mm.). The yield of colorless product is
308–325 g. (
85–90%);
nD20 1.4101,
nD25 1.4081;
d424 0.985,
d410 0.997 (Note
2).