Propene oxide technology

Examples for necessary process improvements through catalyst research are the development of one-step processes for a number of bulk products like acetaldehyde and acetic acid (from ethane), phenol (from benzene), acrolein (from propane), or allyl alcohol (from acrolein). For example, allyl alcohol, a chemical which is used in the production of plasticizers, flame resistors and fungicides, can be manufactured via gas-phase acetoxylation of propene in the Hoechst [1] or Bayer process [2], isomerization of propene oxide (BASF-Wyandotte), or by technologies involving the alkaline hydrolysis of allyl chloride (Dow and Shell) thereby producing stoichiometric amounts of unavoidable by-products. However, if there is a catalyst... 

It has recently been found that NEt3 is a gas-phase promoter for propene epoxidation by supported gold catalysts [245]. In more recent studies, Hughes et al. reported that catalytic amounts of peroxides could initiate the oxidation of alkenes with 02, without the need for sacrificial H2 [243]. The process worked for a range of substrates (cyclohexene, ds-stilbene, styrene and so on) and even in the absence of solvent hence, we may refer to this as green technology. 

The oxidation of propene to acrolein has been applied in industry since 1958, when Shell introduced a gas-phase oxidation based on a Cu20/SiC/l2 catalyst system. This process made acrolein a commodity product. A more efficient technology, still state-of-the-art, was subsequently developed by Standard Oil of Ohio (from 1957 onward), using bismuth molybdate and bismuth phosphatecatalysts... 

Currently, the industrial production of PO mainly comes from the oxidation of propene with other chemicals. The main technologies employed in its production are outlined below [2]. 

Several companies are working on the direct oxidation of propene for instance Lyondell is operating a pilot plant in Newtown Square, PA, and intends to commercialize the technology by 2010. Shell Chemical is also working on a direct route to PO production, based on variations of the gold and silver catalysts it uses to make ethene oxide. 

The catalytic dehydrogenation of lower alkanes was first developed more than fifty years ago using chromia/alumina systems [1]. Although there has been development of new processes [2 - 6], the catalyst technology has tended to remain with either modified chromia/alumina or modified platinum/alumina catalysts. Therefore it seemed appropriate to re-examine the possibility of using oxide systems other than chromia to effect the alkane to alkene transition. Supported vanadium pentoxide has been extensively studied for the oxidative dehydrogenation of propane to propene [7-10] but rarely for the direct dehydrogenation reaction [6]. 

Propene gives acetone and a small amount of propionaldehyde on oxidation under Wacker conditions, that is, in the presence of PdCl2 and CuClj. A commercial process has been developed by Hoechst AG, and two plants have been erected in Japan. The process is carried out by the two-stage technology. A regeneration step is also used to decompose copper oxalate thermally. Propionaldehyde is removed by distillation together with the light ends and isolated by a separate distillation step [37, 38]. 

Epoxide- and Diol-Building Blocks (ChiRex). The latest technology for producing chiral epoxides and 1,2-diols is Jacobsen s hydroljdic kinetic resolution, technically developed by ChiRex for resolving propene and styrene oxide as well as epichlorohydrin on a multi-lOO-kg scale Qh,63). The technology was licensed to Daiso Co. for epichlorohydrin resolution on a multitons per year scale (64). 

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