Oxidative Dehydrogenation of Propane to Propene

Fig. 42. Catalyst screening for the oxidative dehydrogenation of propane to propene. T = 823 K molar ratios C3H8/02/N2/H20 = 5/25/25/45 GHSV = 1300 h-1 mcat = 1.4 - 8.0 g vcat = 5 ml [from Schuster et al. (259)].

Vanadia catalysts exhibit high activity and selectivity for numerous oxidation reactions. The reactions are partial oxidation of methane and methanol to formaldehyde, and oxidative dehydrogenation of propane to propene and ethane to ethcnc.62 62 The catalytic activity and selectivity of... 

Fic . 2. Selectivity for oxidative dehydrogenation of propane to propene. Data taken from Table 4. Solid line denotes selectivity-conversion relationship for kA = kt. ... 

Ramos, R. Pina, M.P. Menendez, M. Santamaria, J. Patience, G.S. Oxidative dehydrogenation of propane to propene simulation of a commercial inert membrane reactor immersed in a fluidized bed. Can. J. Chem. Eng. 2002, 79, 902-912. 

An alternative approach is to combine the two steps, that is, the oxidative dehydrogenation of propane to propene and the epoxidation of propene to PO, in a single reactor, with two sequential catalytic beds, but with similar reaction conditions for the two steps [45b]. The problem is that most of the active and selective catalysts in propane ODH operate at temperatures that are too high for propene epoxidation. 

The catalytic dehydrogenation of lower alkanes was first developed more than fifty years ago using chromia/alumina systems [1]. Although there has been development of new processes [2 - 6], the catalyst technology has tended to remain with either modified chromia/alumina or modified platinum/alumina catalysts. Therefore it seemed appropriate to re-examine the possibility of using oxide systems other than chromia to effect the alkane to alkene transition. Supported vanadium pentoxide has been extensively studied for the oxidative dehydrogenation of propane to propene [7-10] but rarely for the direct dehydrogenation reaction [6]. 

Buyevskaya, O., Bruckner, A., Kondratenko, E., et al. (2001). Fundamental and Combinatorial Approaches in the Search for and Optimisation of Catalytic Materials for the Oxidative Dehydrogenation of Propane to Propene, Catal. Today, 67, pp. 369-378. 

Buyeskaya, O.V., Bruckner, A., Kondratenko, E.V., Wolf, D., and Baerns, M. Fundamental and combinatorial approaches in the search for optimisation of catalytic materials for the oxidative dehydrogenation of propane to propene. Catal. 

Liu, Y, Wang, J., Zhou, G., Mo Xian, Bi, Y, and Zhen, K. Oxidative dehydrogenation of propane to propene over barium promoted Ni-Mo-O catalyst. React Kinet. Catal. Lett. 2001, 73, 199. 

A rectangular area R with borders perpendicular to axes, defining the consequence (the THEN... part) of a rule to extract, has to be chosen in advance in the output space of a trained multilayer perceptron. T q)ically, this is specified by means of an inequality constraint on some of the output variables, e.g., yi > 9%, or by means of a combination of such constraints, e.g., ji > 8% y2>i.5%. For illustration, assume that an MLP has two output neurons corresponding to the output variables yi and j2 such thatyi records the yield of propene in an oxidative dehydrogenation of propane to propene, andj2 records the yield of ethylene in the reaction. Then the former condition reads... 

FIGURE 10.1 A summary of reported selectivity-conversion relationships in the oxidative dehydrogenation of propane to propene. Solid line is the relationship for a sequential reaction of propane to propene to CO if the first-order reaction constants for the two steps are identical. Open circles are data for homogeneous noncatalytic reaction. 

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