Oxiranes Oxidation with Organic Hydroperoxides

Epoxidation with hydroperoxides is the basis for the large-scale indirect production of propylene oxide by a process that has been called the Oxirane or Halcon processes. Early work was reported by Smith in a patent issued in 1956 [457], which described soluble heteropoly acids containing transition metals such as chromium, molybdenum, and tungsten that could be employed as homogeneous catalysts for the reaction of olefins with organic hydroperoxides and hydrogen peroxide. 

Styrene, one of the world s major organic chemicals, is derived from ethylene via ethylbenzene. Several recent developments have occurred with respect to this use for ethylene. One is the production of styrene as a co-product of the propylene oxide process developed by Halcon International (12). In this process, benzene is alkylated with ethylene to ethylbenzene, and the latter is oxidized to ethylbenzene hydroperoxide. This hydroperoxide, in the presence of suitable catalysts, can convert a broad range of olefins to their corresponding oxirane compounds, of which propylene oxide presently has the greatest industrial importance. The ethylbenzene hydroperoxide is converted simultaneously to methylphenyl-carbinol which, upon dehydration, yields styrene. Commercial application of this new development in the use of ethylene will be demonstrated in a plant in Spain in the near future. 

Sumitomo developed a recirculation process for manufacture of PO using CHP as oxidant (196). The company developed both a new catalyst and a new process for PO production. The production method is fundamentally similar to known methods involving organic peroxides as oxidants the major difference is that cumene is used as the reaction medium and hence the process is referred to as the cumene PO-only process. Laboratory tests started in 2000 and pilot plant testing in 2001. A plant was completed in 2002 and started up in 2003. This commercial plant was the first PO-only plant in Japan, producing PO by oxidation of propylene with cumene hydroperoxide without a significant formation of coproducts. The plant is located in the Chiba prefecture, operated by a joint venture between Nihon Oxirane Co. and Lyondell, and produces aroimd 200,000 t of PO/year. A second plant was started in May 2009 in Saudi Arabia, as a joint project of Sumitomo with Saudi Arabian Oil Co. 

---