Chementator: Another one-step route to phenol emerges
By Chemical Engineering |
A single-step process for making phenol from benzene and carbon monoxide has been developed by Daicel Chemical Industries, Ltd. (Tokyo; edlinks.chemengonline.com/5826-543) with cooperation from Yasutaka Ishii, professor of applied chemistry at Kansai University (Osaka, Japan; edlinks.chemengonline.com/5826-544). Other attempts to make phenol directly, such as the reaction of benzene with hydrogen and oxygen over a palladium-membrane reactor (CE, March 2002, p. 15), suffer from poor yields (below 15%), says the firm (see CE, September 2004, p. 17, for other phenol technology).
Normally, three reaction steps are required to make phenol. First, benzene is reacted with propylene to form cumene. The cumene is then oxidized to cumene hydroperoxide, which is subsequently decomposed into phenol and byproduct acetone. In the new process, phenol is directly synthesized in the presence of air (5–10 bars partial pressure) using CO (10–15 bar partial pressure) as a reducing agent. The reaction takes place in an aqueous acetic acid solution at about 90°C using a heteropolyacid catalyst, such as molybdovanado phosphoric acid. In the laboratory, a 25–30% single-pass conversion with 90% selectivity for phenol was achieved. The…