Styrene by dehydrogenation of ethylbenzene

In 1869 Berthelot- reported the production of styrene by dehydrogenation of ethylbenzene. This method is the basis of present day commercial methods. Over the year many other methods were developed, such as the decarboxylation of acids, dehydration of alcohols, pyrolysis of acetylene, pyrolysis of hydrocarbons and the chlorination and dehydrogenation of ethylbenzene." ... 

The production of styrene by dehydrogenation of ethylbenzene is a good example (121). When rates of reaction are high, short diffusion lengths are required, suggesting structured, thin-layered catalytic reactors. When selectivity is an issue, this is even more the case. 

Styrene manufacture by dehydrogenation of ethylbenzene is simple ia concept and has the virtue of beiag a siagle-product technology, an important consideration for a product of such enormous volume. This route is used for nearly 90% of the worldwide styrene production. The rest is obtained from the coproduction of propylene oxide (PO) and styrene (SM). The PO—SM route is complex and capital-iatensive ia comparison to dehydrogenation of ethylbenzene, but it stiU can be very attractive. However, its use is limited by the mismatch between the demands for styrene and propylene oxides (qv). 

Another appHcation for this type catalyst is ia the purification of styrene. Trace amounts (200—300 ppmw) of phenylacetylene can inhibit styrene polymerization and caimot easily be removed from styrene produced by dehydrogenation of ethylbenzene using the high activity catalysts introduced in the 1980s. Treatment of styrene with hydrogen over an inhibited supported palladium catalyst in a small post reactor lowers phenylacetylene concentrations to a tolerable level of <50 ppmw without significant loss of styrene. 

The generation of caibocations from these sources is well documented (see Section 5.4). The reaction of aromatics with alkenes in the presence of Lewis acid catalysts is the basis for the industrial production of many alkylated aromatic compounds. Styrene, for example, is prepared by dehydrogenation of ethylbenzene made from benzene and ethylene. 

Styrene is made by dehydrogenation of ethylbenzene at high temperature using... 

Styrene manufacture by dehydrogenation of ethylbenzene is used for nearly 90% of the worldwide styrene production. The rest is obtained from the coproduction of propylene oxide (PO) and styrene (SM). 

About 10 million tons of styrene and 3.5 million tons of propylene oxide are produced annually, worldwide. Most of the styrene is still produced by dehydrogenation of ethylbenzene and it is estimated that ca. 800,000 tons of styrene and 400,000 tons of propylene oxide are produced by the SMPO process. 

Styrene is produced by dehydrogenation of ethylbenzene in an adiabatic, fixed-bed reactor. Although Sheel and Crowe [29] list ten reactions and several products, the major reaction is the conversion of ethylbenzene to styrene, according to the following equation. 

Styrene (phenylethene, 10) is an important industrial chemical that is prepared by dehydrogenation of ethylbenzene at 600 °C over zinc oxide or chromium(III) oxide on alumina (Scheme 3.7). Ethylbenzene can be produced from benzene and ethene by a Friedel-Crafts reaction. 

Large amounts of styrene are commercially produced by dehydrogenation of ethylbenzene (EB) in the presence of steam using iron oxide-based catalysts. Carbon dioxide, small amounts of which are formed as a by-product in the ethylbenzene dehydrogenation, was known to depress the catalytic activity of commercial catalyst [7,8]. However, it has been recently reported that several examples show the positive effect of carbon dioxide in this catalytic reaction [5,9,10]. In this study, we investigated the effect of carbon dioxide in dehydrogenation of ethylbenzene over ZSM-5 zeolite-supported iron oxide catalyst. 

Fig. 4. Manufacture of styrene by adiabatic dehydrogenation of ethylbenzene A, steam superheater B, reactor section C, feed—effluent exchanger D,...

Other Technologies. As important as dehydrogenation of ethylbenzene is in the production of styrene, it suffers from two theoretical disadvantages it is endothermic and is limited by thermodynamic equiHbrium. The endothermicity requites heat input at high temperature, which is difficult. The thermodynamic limitation necessitates the separation of the unreacted ethylbenzene from styrene, which are close-boiling compounds. The obvious solution is to effect the reaction oxidatively ... 

Problem 16.21 Styrene, the simplest alkenylbenzene, is prepared commercially for use in plastics manufacture by catalytic dehydrogenation of ethylbenzene. How might you prepare styrene from benzene using reactions you ve studied ... 

Styrene (or viuylbenzene) is prepared technically by the cracking dehydrogenation of ethylbenzene ... 

An efficient oxidation catalyst, OMS-1 (octahedral mol. sieve), was prepared by microwave heating of a family of layered and tunnel-structured manganese oxide materials. These materials are known to interact strongly with microwave radiation, and thus pronounced effects on the microstructure were expected. Their catalytic activity was tested in the oxidative dehydrogenation of ethylbenzene to styrene [25]. 

Styrene is to be produced by the catalytic dehydrogenation of ethylbenzene according to the reaction ... 

Data for the process of dehydrogenation of ethylbenzene to styrene in a tubular packed reactor are given by Jenson Jeffreys (Mathematical Methods in Chemical Rngineering, 424, 1977). The energy and material balances are like... 

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