Catalytic Dehydrogenation on Carbon
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lytic Dehydrogenation on Carbon O. A. Knyazhevaa,*, O. N. Baklanovaa,**, and A. V. Lavrenova,*** a
Center of New Chemical Technologies, Boreskov Institute of Catalysis, Siberian Branch, Russian Academy of Sciences, Omsk, 644040 Russia *e-mail: [email protected] **e-mail: [email protected] ***e-mail: [email protected] Received February 14, 2020; revised April 29, 2020; accepted July 15, 2020
Abstract—The formation of hydrocarbon dehydrogenation catalysts whose active centers are determined by the presence of oxygen-containing functional groups located on the surface of a porous carbon material rather than by their nontransition metal or metal oxide constituents was considered. The prospects of using carbon catalysts instead of traditional metal/metal oxide systems in the direct and oxidative dehydrogenation reactions of propane and ethylbenzene were shown. Keywords: carbon, functional groups, carbon catalysts, hydrocarbon dehydrogenation DOI: 10.3103/S0361521920060051
Carbon materials are widely used in heterogeneous catalysis, primarily, as supports for metal and oxide catalysts for various redox processes. In order to reduce the cost, increase the selectivity of action, and minimize environmental pollution, a number of researchers are engaged in the research and development of solid systems that do not contain transition metals or their oxides but are efficient for practical use, in particular, in hydrocarbon dehydrogenation reactions [1]. Carbon materials with a functionalized surface are also considered as a basis for alternatives to traditional systems [1–3]. Along with the dehydrogenation of hydrocarbons, carbon materials with oxygen-containing groups on the surface can participate in the dehydration of alcohols and the reduction of nitrogen oxides [4] (Table 1). Graphite, carbon black, multiwalled carbon nanotubes, and activated carbons are used for the production of carbon catalysts [2, 3]. The most important advantages of carbon to be used for the preparation of catalysts are its stability and resistance to aggressive media, developed porosity, and the possibility of embedding heteroatoms directly into the structure of a carbon material. This paper briefly considers the functionalization of carbon materials by the formation of oxygen-containing groups on their surfaces and exemplifies the effects of functional groups on the manifestation of catalytic properties. Methods for the surface functionalization of carbon materials. Oxidation is the most common method for applying oxygen-containing functional groups onto
the surface of a carbon material. Figure 1 shows acidic oxygen-containing (phenolic, carboxyl, lactone, and anhydride) groups and basic oxygen-containing (ether, carbonyl, quinone, and pyrone) groups formed on the carbon surface as a result of oxidative treatment [4, 5]. The traditional way of oxidizing carbon materials is liquid-phase functionalization with the use of oxidizing systems such as mineral acids and their mixtures based on HNO3, HNO3 + H2SO4, HClO4, KMnO4, etc. [6–14]. It is well known tha
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