Hexamethylene glycol (CAS NO.: ), which is also known as , could be produced through the following synthetic routes.

In a steel reaction vessel, capable of withstanding high pressures with an adequate safety factor and having a capacity of 400 cc. or more, are placed 252 g. (1.25 moles) of ethyl adipate (b.p. 144–145°/29 mm.) (p. 264) and 20 g. of copper chromite catalyst, prepared either with or without the addition of barium (p. 142). The reaction vessel is closed, made gas tight, and secured in a suitable agitating device. After connection is made with the hydrogen supply, hydrogen is introduced until a pressure of 2000 to 3000 lb. per sq. in. is reached.

Agitation is started, and the reaction system is heated as rapidly as possible to 255°. The temperature is maintained at 255°, and hydrogenation is continued until hydrogen absorption is complete. The agitation is now stopped, the vessel cooled, and the pressure released. With the aid of four 25-cc. portions of 95 per cent alcohol the reaction mixture is transferred to a 600-cc. beaker. The catalyst is removed by filtering or centrifuging, and is washed with four more 25-cc. portions of alcohol. To the reaction product, 50 cc. of 40 per cent sodium hydroxide solution is added, and the alcoholic solution is boiled for two hours under a reflux condenser. The mixture is transferred to a 1-l. distilling flask and the alcohol removed by distilling to a vapor temperature of 95°. The hot residue is transferred to an apparatus for the continuous extraction of liquids (p. 615), using 50 cc. of water to rinse the flask, and the solution is exhaustively extracted with ether. The ether is distilled, and, after the removal of water and alcohol, the glycol is distilled under reduced pressure in a 250-cc. Claisen flask. The yield is 125–132 g. (85–90 per cent of the theoretical amount). Hexamethylene glycol boils at 143–144° (bath at 160°) under 4 mm. pressure and melts at 41–42°.