The increasing demand for light olefins and the insufficient capacity from current production by steam and catalytic cracking are the driving forces to seek alternative ways to manufacture these chemicals. The most feasible processes on a commercial scale at present are catalytic dehydrogenation (DH) and oxidative dehydrogenation (ODH) of light alkanes. Raman spectroscopy was used to investigate the structural changes of surface VOx and the coke formation process during butane DH over V/δ-Al2O3 catalysts with various surface VOx densities. A better understanding of coke formation chemistry and the role of different VOx species in coke formation could facilitate optimization of catalysts and possible reduction of side reactions leading to coke. Raman spectra from 1,3-butadiene DH on 1.2 V sample showed some different features from other olefins and butane at reaction temperatures below 573 K. These two bands were readily formed upon room temperature adsorption of 1,3-butadiene on the 1.2 V sample and persisted from reaction temperature ≤ 773 K. The two bands observed at room temperature could be removed after heating in He at 573 K, suggesting they were due to adsorbed 1,3-butadiene on the V/δ-Al2O3 sample. The two bands at ∼ 850 and 1006/cm observed upon the reaction of C4 olefins and butane on VOx samples were related to a -CH=CH2 structure but not exactly 1,3-butadiene. Coke species formed on polymerized VOx were more easily removed than on isolated VOx. This is an abstract of a paper presented at the ACS Fuel Chemistry Meeting (San Diego, CA Spring 2005).
|Number of pages||2|
|Journal||ACS Division of Fuel Chemistry, Preprints|
|Publication status||Published - Jul 26 2005|
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