Styrene: Ethylbenzene and Steam over a Magnesia-Iron Oxide Catalyst

Styrene is ethylbenzene with two hydrogen atoms taken off, the 'S' in ABS. Kearby's process (US 2,395,875, 1946) passes the hydrocarbon with plenty of steam over a catalyst of magnesia with iron oxide and a little potassium and copper oxide at 1100–1300 °F (about 590–700 °C). The steam dilutes the vapour and burns off coke, and the catalyst is regenerated every few hours. The patent's worked figures are for butene; for ethylbenzene it gives these general conditions, which we use. The picture: our diagram.