A
500-ml. flask is charged with
318 g. (3 moles) of 1,2,4-trihydroxybutane (Note
1) and
3 g. of p-toluenesulfonic acid monohydrate. A few
Carborundum boiling chips are added, the flask is equipped with a
30.5-cm. Vigreux column, condenser, and
receiver arranged for vacuum distillation, and the contents are heated, with swirling, to dissolve the acid (Note
2). The flask is then heated in a bath held at 180–220° so that 300–306 g. of distillate, b.p. 85–87°/22 mm., is collected over a period of 2–2.5 hours (Note
3). The colorless liquid obtained is refractionated, the same apparatus being used, and two fractions are collected: the first, 50–60 g., b.p. 42–44°/24 mm.,
nD25 1.3343, is mainly water. After a negligible intermediate fraction,
215–231 g. (
81–88%) of pure
3-hydroxytetrahydrofuran, b.p.
93–95°/26 mm.,
nD25 1.4497,
d420 = 1.095, is collected (Note
4).