Styrene development dehydrogenation

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." ... 

Rhenium oxides have been studied as catalyst materials in oxidation reactions of sulfur dioxide to sulfur trioxide, sulfite to sulfate, and nitrite to nitrate. There has been no commercial development in this area. These compounds have also been used as catalysts for reductions, but appear not to have exceptional properties. Rhenium sulfide catalysts have been used for hydrogenations of organic compounds, including benzene and styrene, and for dehydrogenation of alcohols to give aldehydes (qv) and ketones (qv). The significant property of these catalyst systems is that they are not poisoned by sulfur compounds. 

Because much toluene is demethylated for use as benzene, considerable effort has been expended on developing processes in which toluene can be used in place of benzene to make directiy from toluene the same products that are derived from benzene. Such processes both save the cost of demethylation and utilize the methyl group already on toluene. Most of this effort has been directed toward manufacture of styrene. An alternative approach is the manufacture of i ra-methylstyrene by selective ethylation of toluene, followed by dehydrogenation. Resins from this monomer are expected to displace... 

The Cu+/zeolite-catalyzed cyclodimerization of 1,3-butadiene at 100°C and 7 atm was found to give 4-vinylcyclohexene [Eq. (13.12)] with high (>99%) selectivity. Subsequent oxidative dehydrogenation over an oxide catalyst in the presence of steam gives styrene. The overall process developed by Dow Chemical113 offers an alternative to usual styrene processes based on ethylation of benzene (see Section 5.5.2). 

Another interesting recent development in styrene technology which will affect future consumption of ethylene relates to new methods for increasing conversion in the dehydrogenation of ethylbenzene. Several years ago, Scientific Design pioneered a technique for increasing conversion in this reaction. The net result was a marked decrease in the capital investment required for styrene plants. The present trend is to-... 

Butadiene (bpi.oi3= —4.413 C, 44 =0.6211) has become a major petrochemical product thanks to the development of its copolymers with styrene and acrylonitrDe. The earliest processes for manufacturing butadim started with acetylene and formaldehyde (Germany, the Reppe process), or produced it by the alUnited States Unwn Carbide). 

Styrene is manufactured nearly entirely by the direct dehydrogenation of ethylbenzene. Smaller amounts are obtained indirectly, as a co product, from the production of propy. lene oxide by the Oxirane and Shell technologies, industrialized in the United States, the Netherlands and Spain, and whose essential intermediate step is the formation of ethylbenzene hydroperoxide, or from the production of aniline, by a technique develop jn the USSR, which combines the highly exothermic hydrogenation of nitrobenzene with the highly endothermic dehydrogenation of ethylbenzene. 

Central to Germany s development of polystyrene technology was Herman F. Mark (Figure 1.4). Mark worked at I. G. Farben Industrie for 6 years from 1927 to 1932, first as a research chemist (1927-28), then as Group Leader (1928-30) and finally as Assistant Research Director (1930-32). Because of the changing political climate, Mark moved to the University of Vienna, where he became Professor of Chemistry and Director of the First Chemical Institute (1932-38). While at I. G. Farben Industrie, Mark played a major role in the development of styrene monomer and PS. Mark patented a process in 1929 for the production of styrene from ethylbenzene via catalytic dehydrogenation [8]. 

Commercially, the best way to prepare 1,1-DPE is probably to react styrene and benzene with one another and then to dehydrogenate the resulting 1,1-diphenylethane to 1,1-diphenylethylene. This has been developed to the pilot plant stage in BASF [7]. 

Aside from EB dehydrogenation, the only other commercial-scale production of styrene is through a propylene oxide/styrene process that produces roughly 15% of worldwide styrene. This technology was developed as an alternative to the chlorohydrin method for producing propylene oxide. 

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