cyanohydrin (CAS NO.: ), with other name of β-hydroxypropionitrile, could be produced through the following synthetic routes.

In a 5-l. flask is placed 612 g. (12.5 moles) of finely powdered sodium cyanide (passed through a meat grinder and then sifted through a 20-mesh sieve); the flask is equipped with a thermometer in a well, an efficient stirrer, and a reflux condenser. The whole vessel is then set in a water bath into which warm and cold water can be run at will and if necessary rapidly removed.

A mixture of 250 cc. of water and 1 kg. (807 cc., 12.4 moles) of pure ethylene chlorohydrin (b.p. 126–127°) is then added, the stirring is started, and the temperature of the mixture raised to 45° by external application of warm water. At this point the warm water is rapidly removed and the temperature of the contents of the flask carefully held at 45° by jacketing with water at a suitable temperature (33–35°). After the mixture has been held at 45° for one hour it is allowed to warm up to 48° by allowing the temperature of the water bath to rise about 2°. After an hour at 48° the temperature is raised to 50° and held at this point until the reaction is over; it is necessary to raise the temperature of the bath gradually, and the end of the reaction is noted when the bath temperature reaches 50°. A period of four and one-half to five hours is necessary for this last stage.

Cold water is now placed in the water bath, while the stirrer is kept always in motion, and the temperature of the mixture is reduced to 20–22°. The mass is then filtered by suction and the sodium chloride sucked as dry as possible. This is then washed with about 800 cc. of acetone in small quantities, the washings being collected separately, and then transferred to a flask from which the acetone and water are distilled off with the use of a short fractionating column until the temperature of the vapor reaches 90°. The residue in the flask is then cooled and again filtered from a further small quantity of sodium chloride which separates during the distillation, the filtrate being added to the main product.

This is then distilled under reduced pressure from an oil bath, and the fraction boiling at 107–109°/12 mm. (116–118°/20 mm.) is collected as pure material. The yield is 700–705 g. (79–80 per cent of the theoretical amount). There is practically no residue beyond a little salt; the foreruns consist of water, a small amount of unchanged ethylene chlorohydrin, and some ethylene cyanohydrin.