Oxidative dehydrogenation of ethylbenzene

J.N. Michaels, and C.G. Vayenas, Kinetics of Vapor-Phase Electrochemical Oxidative Dehydrogenation of Ethylbenzene,/. Catal. 85, 477-488 (1984). 

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]. 

Selective partial oxidation of hydrocarbons poses considerable challenges to contemporary research. While by no means all, most catalytic oxidations are based on transition-metal oxides as active intermediates, and the oxidative dehydrogenation of ethylbenzene to styrene over potassium-promoted iron oxides at a scale of about 20 Mt/year may serve as an example [1]. Despite this... 

The central ions in (oxy)chloride metal complexes are in a high oxidation state that is preserved during anchoring (Eq. 5) and grafting. Therefore, these grafted catalysts are mainly used to catalyze oxidation reactions, e.g. oxidative dehydrogenation of ethylbenzene [31], oxidation of acrolein [29], methanol [10], and 0-xylene [30, 37],... 

Kito and Hattori et al. have described INCAP (IN-tegration of Catalyst Activity Patterns [21-23]), an expert system which rates the applicability of catalyst components for the desired reaction based on known activity patterns for different catalyst properties. The system was successfully applied for the selection of promoter components for the oxidative dehydrogenation of ethylbenzene to styrene. An improved version INCAP-MUSE (INCAP for MUlti-Componcnt catalyst SElcction [24-26]) selects as many catalyst components until all required catalyst properties are present. Although the system was successfully applied to oxidation reactions, more recently better results have been obtained by neural network methods (Section 2.6.2.2). 

In heterogeneous catalysis the applicability of this method has been demonstrated. The method is explained below for the acid-catalyzed oxidative dehydrogenation of ethylbenzene as used by Kito ct al. [37-41] aiming at maximizing the selectivity to styrene by promoting SnOi with various inorganic compounds. 

When applying a series of promoted and unpromoted SnO catalysts for the oxidative dehydrogenation of ethylbenzene, the artificial neural network was able to predict the observed sclcctivitics with an average absolute error of only 1.5% (Fig. 3). These results arc much better than those obtained by the expert system INCAP (see Section 2.6.2.1), where the average absolute error for the styrene selectivity was about 20 /,.. 

Other oxidation/reduction related reactions are also explored with ceria based catalysts. For example, Murugan and Ramaswamy (2007) reported the oxidative dehydrogenation of ethylbenzene on nanocrystal-line ceria using N2O as the oxidant Concepcion et al. (2004) reported the chemoselective hydrogenation of crotonaldehyde catalyzed by Ft on mesostructured Ce02 NPs embedded within layers of Si02 binder. 

The oxidation of intracrystalline ammonium cations has been reported 3, 65), but most oxidations over zeolites featuring molecular oxygen-hydrocarbon systems have featured transition metal zeolites. The oxidative dehydrogenation of ethylbenzene to styrene and selective oxidation of benzyl alcohol to benzaldehyde over MnY at 250°-370°C were reported earlier 62). Propylene has been oxidized to formaldehyde, COo, and minor quantities or acrolein and acetaldehyde over Cu( II)-exchanged Y-type zeolite (39). 

Tiscareno-Lechuga F, Hill Jr. G.C. and Anderson M.A., Experimental studies of the non-oxidative dehydrogenation of ethylbenzene using a membrane reactor, Appl. Catal. 96 33 (1993). 

Oxidative dehydrogenation of ethylbenzene with carbon dioxide over ZSM-5-supported iron oxide catalysts... 

The diversity of the important catalytic reactions used in industry and the difficulty of ensuring rigorous and detailed investigations for each reaction. In fact some important catalytic reactions have no published intrinsic kinetics (e.g. non-oxidative dehydrogenation of ethylbenzene to styrene) and others for which the literature offers only oversimplified power law kinetics. 

On the other hand, zeolites may serve as cocatalysts or as a carrier for oxidising cations. This is the case of R,Fe-Y zeolite an active catalyst in the oxidation of CO or NO (Aparicio et al. 1988) or Fe-Gd-K-O/mordenite and Fe-Tb-K—O/clinoptilolite catalysts which give a yield of 45-75% styrene from the oxidative dehydrogenation of ethylbenzene (Alimardanov and Addullayev 1996). 

The oxidative dehydrogenation of ethylbenzene (ODE) is an alternative route to styrene, which is currently produced by dehydrogenation (DE) ... 

Figure 6.3 Mechanism proposed for the oxidative dehydrogenation of ethylbenzene. (Adapted from ref. 46.)...

Recently, the remarkable properties of carbon nanotubes (CNTs) and related structures, such as carbon nanofibers (CNFs) and onionlike carbons, have attracted an increasing interest from the catalysis community [66], Although these materials are most often used as supports for active phases, some applications as catalysts have been reported, the oxidative dehydrogenation of ethylbenzene to styrene being the most frequently cited example [67-73], These reports basically confirm the mechanism proposed previously, based on a redox cycle involving the quinone surface groups. 

Then catalyzed oxidative dehydrogenation of ethylbenzene to afford styrene occurs. 

Grunewald, G. C., and R. S. Drago. 1990. Oxidative dehydrogenation of ethylbenzene to styrene over carbon-based catalysts. J. Mol. Catal. 58 227-233. 

Oxidative dehydrogenation of ethylbenzene Room-temperature CO oxidation... 

Catalytic activity of carbon nanotubes and other carbon materials for oxidative dehydrogenation of ethylbenzene to styrene... 

Murakami, Y., Iguayama, K., Huchida, H., Hattori, T., Tagawa, T. "Study of the oxidative dehydrogenation of ethylbenzene I. Catalytic behavior of Sn02-P20s" J. Catal., 71, 257 (1981). 

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