Oxydehydrogenation of ethylbenzene to styrene in the presence of CO2 on the catalysts obtained from [Li(Fe,Al)2(OH)6]CO3.xH2O precursors

Li-Fe,Al oxide system has been proposed as the effective catalysts for ethylbenzene (EB) dehydrogenation with CO2 used as an oxidant. All the samples were characterised by chemical and phase analysis. TPR-H-2 as well as TPD-NH3 and -CO2 were used to determine redox and acid/base properties of the samples. The best catalytic performance was found for the catalysts containing 15-45 wt.% of Fe. Reduction of iron in such materials occurred at higher temperatures. Moreover, the most active catalysts showed higher fraction of the strong acid/base sites, though their total number was diminished with increasing of Fe content. The activity and selectivity of the catalysts in the standard dehydrogenation of EB in the presence of water steam were much worse than those obtained with CO2 as an oxidant. Using CO2 instead of H2O results in decrease of acidic Bronsted centres concentration formed in the course of oxidative dehydrogenation of EB. (C) 2003 Elsevier B.V. All rights reserved.