A 1-l. round-bottomed flask is fitted with a 30-cm. Vigreux column (Note 1) connected to a condenser. The condenser leads to an automatic separator arranged so that the lighter liquid is returned to the flask.¹ In the flask is placed a mixture of 189 g. (167 ml., 2 moles) of trimethylene chlorohydrin,² 180 g. (172 ml., 3 moles) of glacial acetic acid, 300 ml. of benzene, and 2 g. of p-toluenesulfonic acid monohydrate. The mixture is refluxed at such a rate that the temperature at the top of the column remains at 69° (boiling point of benzene-water azeotrope) during the time the greatest amount of water is distilling, and rises gradually to 80° (boiling point of benzene-acetic acid azeotrope) as the last of the water is removed. The volume of the aqueous layer collected varies with the temperature of the vapors and the length of time required for distillation, but it is approximately 50 ml. at the end of the reaction; the time required is 7–9 hours (Note 2).

The solution is cooled, then washed successively with two 500-ml. portions of 10% sodium carbonate solution, one 500-ml. portion of water, and one 100-ml. portion of saturated sodium chloride solution. The wash solutions are extracted successively with one 100-ml. portion of benzene, which is added to the main benzene solution. After removal of the benzene the ester is distilled at atmospheric pressure through a 30-cm. asbestos-wrapped Vigreux column, the fraction boiling at 166–170°, n_D2 1.4295, being collected. The yield of colorless product is 257–260 g. (93–95%).