Catalytic dehydrogenation process chemistry

Not only the linear Cl0-Cl8 a-olefins but also the linear C10-Cl8 olefins with internal double bonds, the so-called -v /-olefins, are of great importance in surfactant chemistry, n-a-Olefins and n-y-olefins have the same suitability for the manufacture of linear alkylbenzenes, the most important synthetic anionic surfactants, by alkylation of benzene. Nowadays medium molecular weight n- /-olefins are industrially produced by two processes the catalytic dehydrogenation of the corresponding n-alkanes [4,28] and the cometathesis of low and high molecular weight n-v /-olefins, obtained by double-bond isomerization of the isomeric n-a-olefins [29]. 

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]. 

In this chapter, we have discussed the application of metal oxides as catalysts. Metal oxides display a wide range of properties, from metallic to semiconductor to insulator. Because of the compositional variability and more localized electronic structures than metals, the presence of defects (such as comers, kinks, steps, and coordinatively unsaturated sites) play a very important role in oxide surface chemistry and hence in catalysis. As described, the catalytic reactions also depend on the surface crystallographic structure. The catalytic properties of the oxide surfaces can be explained in terms of Lewis acidity and basicity. The electronegative oxygen atoms accumulate electrons and act as Lewis bases while the metal cations act as Lewis acids. The important applications of metal oxides as catalysts are in processes such as selective oxidation, hydrogenation, oxidative dehydrogenation, and dehydrochlorination and destructive adsorption of chlorocarbons. 

Metal oxide-based materials are widely employed as catalysts for a wide number of applications, particularly in processes such as dehydrogenation and oxidation, where redox chemistry is important The structure of metal oxides facilitates these reactions through the transfer of oxygen, or the removal of hydrogen. In order to fully understand the structural dependence of these processes, and hence to refine existing catalysts and catalytic processes and to develop new active materials, it is... 

The characteristics of dehydrogenation coking vary with the chemistry of the catalytic process. Important features are best considered with three important examples (1) catalytic reforming, (2) hydrotreating, and (3)... 

Dehydrocyclisation of alkanes to aromatic compounds is one of the basic reactions of naphtha reforming, which is one of the most important industrial catalytic processes. IThe nature of the ring closure step is one of the main questions of understanding the chemistry of dehydrocyclisation. Sharan reviewed earlier work on tracer studies of this reaction.[ 1 An excellent discussion on the development of ideas and the role of [ C] isotope in elucidating reaction pathways has been published by Davis.Two basic ideas have competed in Scheme 2. One assumed stepwise dehydrogenation of open-chain alkanes then cyclisation as one of... 

Whereas the appropriate forms of zeolites and related solids are widely used in acid-catalysed industrial processes, microporous solids are not currently of importance in commercial base-catalysed conversions. Instead, high-surface-area forms of alkali metal and alkaline earth metal oxides and hydroxides, often supported on alumina, fulfil the need for solid base catalysts. Nevertheless, interest remains in characterising basic sites in cationic zeolites and in developing routes to more strongly basic sites in microporous solids." Routes to the latter include the introduction of metallic forms of alkali metals or nanoparticles of metal oxides and the partial replacement of amine groups at the sites of framework oxygen atoms. Porous solid bases have been shown to exhibit a varied catalytic chemistry, particularly for reactions such as dehydrogenations,... 

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