Ethylbenzene: Ethylene Bubbled through Benzene over an Aluminium Chloride Complex

Ethylbenzene is benzene with an ethyl group added, the raw material for styrene. Dow's continuous plant (Amos, Williams and Winnicki, US 2,222,012, 1940) runs benzene down a packed tower against rising ethylene. The real catalyst is a brown liquid complex of aluminium chloride, made fresh by passing part of the circulating liquor over solid aluminium chloride held in a wire basket, so no solid chloride ever meets the gas. Part of the liquor is drawn off and distilled. The patent gives no temperatures or rates. The picture: the patent's drawing.