Oxidative dehydrogenation of butane

Figure 3. Differential heat of reoxidation and selectivity for oxidative dehydrogenation of butane on V2O5/Y-AI2O3 samples, a 8.2 V/nm sample, reaction at 400°C and b 2.9 V/nm sample, reaction at 480°C.

Figure 4. Dependence of selectivity for oxidative dehydrogenation of butane over orthovanadates on the reduction potential of the cations. Reaction conditions 500°C, butane/Oz/He = 4/8/88, butane conversion = 12.5%.

The data in Figs. 3 and 4 show that the ease of removal of a lattice oxygen, which can also be expressed in terms of the reducibility of the neighboring cations, has a strong effect on the selectivity for oxidative dehydrogenation of butane. If this is the only factor that determines selectivity, then a catalyst that is selective for dehydrogenation of butane, such as Mg3(V04)2, will be selective for other alkanes as well. Likewise, any catalyst that contains bonds will not be... 

There are fewer studies of oxidative dehydrogenation of butane, and even fewer for cyclohexane than ethane or propane. The performance of the better catalysts in these two reactions are summarized in Table VII and Fig. 5. Because of the larger number of secondary carbon atoms in these molecules, they are more reactive with gaseous oxygen than the smaller alkanes. In ex-... 

Fig. 7. Differential heat of reoxidation and selectivity for oxidative dehydrogenation of butane on V2Ov y -AFO, samples. For the 2.9 V/nm2 sample, the selectivity was calculated for the detected gaseous products, (a) 8.2 V/nm2 sample, reaction at 400°C (b) 2.9 V/ntn2 sample, reaction at 480°C (c) 8.2 V/nm2 sample, reduction by CO at 530°C, butane reaction at 400°C and (d) 2.9 V/nm2 sample, reduction by CO at 400°C, butane reaction at 480°C. (a) and (b) are from Ref. 50 (c) and (d) and from P. J., Andersen, Ph D. thesis, Northwestern University, 1992.

Spinel oxides with a general formula AB2O4 (i.e. the so-called normal spinels) are important materials in industrial catalysis. They are thermally stable and maintain enhanced and sustained activities for a variety of industrially important reactions including decomposition of nitrous oxide [1], oxidation and dehydrogenation of hydrocarbons [2], low temperature methanol synthesis [3], oxidation of carbon monoxide and hydrocarbon [4], and oxidative dehydrogenation of butanes [5]. A major problem in the applications of this class of compound as catalyst, however, lies in their usually low specific surface area [6]. 

Catalysts based on transition metal molybdates, typically bismuth, cobalt and nickel molybdates [2-6], have received recent attention. Of the transition metal molybdates, those based on nickel, and in particular the stoichiometric NiMo04, have attracted the greatest interest. NiMo04 presents two polymorphic phases at atmospheric pressure a low temperature a phase, and a high temperature P phase [2,7]. Both phases are monoclinic with space group dim. These phases differ primarily in the coordination of molybdenum which is distorted octahedral in the a phase and distorted tetrahedral in the P phase. The P phase has been shown to be almost twice more selective in propene formation than the a phase for comparable conversion at the same temp>erature [2]. A similar effect has been noted for oxidative dehydrogenation of butane, with the P phase being approximately three times more selective in butene formation than the a phase [8]. The reason for the difference in selectivities is unknown, but the properties of the phases are known to be dependent on the precursors from which they are derived. Typically, nickel molybdates are prepared by calcination of precipitated precursors. 

At present there are a few industrial alkane oxidation processes, for example, the synthesis of maleic anhydride by oxidation of butane [32], and the synthesis of butenes and 1,3-butadiene by oxidative dehydrogenation of butane [33]. The most difficult problem with alkanes is to stop the oxidation at the stage of a necessary product, since oxidation of gaseous hydrocarbon on a solid... 

Oxidative Dehydrogenation of Butane Using Membrane Reactors. AIChE Journal, 43(3) 777-784. 

Oxidative dehydrogenation of butanes and butenes. Since dehydrogenation is endothermic the above process requires reduced pressure and high temperature to be effective. In order to drive the reaction towards completion an oxidative system is used to react with the hydrogen and yields per pass as high as 80% have been claimed. 

Tellez C., Mendndez M. and Santamarfa J. (1997). Oxidative dehydrogenation of butane using membrane reactors, AIChE J., 43, pp. 777-784. 

Owens, L. and Kung, H. (1992). Effects of Loading and Cesium Modifier on Silica-Supported Vanadia in Oxidative Dehydrogenation of Butane, Preprints-American Chemical Society, Division of Petroleum Chemistry, 37(4), pp. 1194-1200. 

Ge, S., Liu, C., Wang, L.J. (2001). Oxidative Dehydrogenation of Butane Using Inert Membrane Reactor with a Non-Uniform Permeation Pattern, Chem. Eng. J., 84, pp. 497-502. 

Ge S, Liu C, Zhang S, Li Z (2003) Effect of carbon dioxide on the reaction performance of oxidative dehydrogenation of -butane over V-Mg-O catalyst. Chem Eng J 94 121-126... 

Chaar, M.A., Patel, D., Kung, M.C., and Kung, H.H. Selective oxidative dehydrogenation of butane over V-Mg-O catalysts. J. Catal 1987,105, 483. Kung, M.C. and Kung, H.H. The effect of potassium in the preparation of magnesium orthovanadate and pyrovanadate on the oxidative dehydrogenation of propane and butane. J. Catal 1992, 134, 668. 

Owen, O.S. and Kung, H.H. Effect of cation reducibihty on oxidative dehydrogenation of butane on orthovanadates. J. Mol Catal 1993, 79, 265. 

Vidal-Michel, R. and Hohn, K.L. Effect of crystal size on the oxidative dehydrogenation of butane on V/MgO catalysts. 7. Catal. 2004, 221,127. 

Madeira, L.M., Maldonado-Hodar, F.J., Portela, M.F., Freire, F., Martm-Aranda, R.M., and Oliveira, M. Oxidative dehydrogenation of -butane on Cs doped nickel molybdate kinetics and mechanism. Appl. Catal A Gen. 1996,135,137. 

Alfonso, M.J.,Menendez, M. and Santamaria, J. (2002) Oxidative dehydrogenation of butane on V/MgO catalytic membranes. Chemical Engineering Journal, 90,131-138. 

Ge, S.H., Liu, C.H. and Wang, L.J. (2001) Oxidative dehydrogenation of butane using inert membrane reactor with a non-uniform permeation pattern. Chemical Engineering Journal, 84,497-502. 

Figure 9.5 Schematic network of the oxidative dehydrogenation of -butane. Reproduced from [19], With permission from Elsevier.

Figure 9.6 Schematic diagram of the PBMR for oxidative dehydrogenation of butane.

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