Indian Journal of Chemistry Vol. 53A, April-May 2014, pp. 493-498 Molybdenum oxide supported on COK-12: A novel catalyst for oxidative dehydrogenation of ethylbenzene using CO 2 Ramudu Pochamoni a , Anand Narani a , Venkata Ramesh Babu Gurram a , Murali Dhar Gudimella b , P. S Sai Prasad Potharaju a , David Raju Burri a & Kamaraju Seetha Rama Rao a, * a Catalysis Laboratory, CSIR-Indian institute of Chemical Technology, Hyderabad 500 607, India Email: ksramarao@iict.res.in b Chemical Engineering Department, Gayatri Vidya Parishad College of Engineering, Visakhapatnam, India Received 6 December 2013; revised and accepted 13 February 2014 P6m-type mesoporous silica (COK-12) prepared at quasi-neutral pH in a buffered medium using sodium silicate as a silica source has been used as a support to prepare a series of MoO 3 /COK-12 catalysts with variable MoO 3 loadings by wet impregnation technique. Among these catalysts, 14 wt% MoO 3 /COK-12 with small particle size of MoO 3 shows superior activity for the oxidative dehydrogenation of ethylbenzene to styrene in the presence CO 2 . Keywords: Catalysts, Supported Catalysts, Dehydrogenation, Oxidative dehydrogenation, Ethylbenzene, Styrene, Molybdenum oxide, Mesoporous silica, Silica Selective dehydrogenation of alkanes to the corresponding olefins is an important catalytic process. For reactions limited by thermodynamic equilibrium (e.g., mostly, dehydrogenation reactions), one of the challenge is to achieve a high conversion with high selectivity towards the products. Among the equilibrium constrained dehydrogenation reactions, styrene from ethylbenzene (EB) is important. Styrene is industrially produced by dehydrogenation of ethylbenzene in vapor phase on several iron oxide catalysts promoted with alkaline metal ions, especially K + , in the temperature range of 873-974 K. However, presently these catalysts are in disuse as the formation of carbonaceous deposits causes a rapid deactivation 1 . KFeO 2 has been identified as the active phase for the dehydrogenation 2–4 wherein potassium enhances the activity of iron oxide and reduces the formation of coke deposits that deactivates the catalysts 5,6 . Co-feeding of steam along with ethylbenzene suppresses the coke formation on the catalyst 7, 8 . An iron oxide-chromium oxide-potassium carbonate based catalyst is used in the industry and improvement of this catalyst is achieved with addition of various metal oxides such as vanadium, cerium, molybdenum, and manganese compounds 9,10 . Wu et al. 11 indicated that TiO 2 -Fe 2 O 3 , ZrO 2 -Fe 2 O 3 , and TiO 2 -Fe 2 O 3 -ZrO 2 showed higher activities than the conventional K-promoted iron catalysts. Jabarathinam et al. 12 have reported that basic sites and acidic sites present in the spinel oxides containing Ni, Cr, Zn, Cu, Fe, and Al catalysts influence the ethyl benzene conversion. On the other hand, the catalytic activities of various metal oxides were investigated for the oxidative dehydrogenation of ethylbenzene to styrene. Oganowski et al. 13 reported that the activity of the V-MgO mixed catalysts could be promoted by Cr, Co, and Mo doping. Moran et al. 14 investigated the dehydrogenation of ethylbenzene to styrene using Pt, Mo, and Pt-Mo catalysts supported on clay nanocomposites. Moronta et al. 15 reported that dehydrogenation of ethylbenzene to styrene catalyzed by Co, Mo and Co-Mo catalysts supported on natural and aluminum-pillared clays, gave low conversions (<20%) and cracking products in the dehydrogenation of ethylbenzene. Burri et al. 16 reported the dehydrogenation of ethylbenzene to styrene was carried out by using CO 2 gas over TiO 2 -ZrO 2 bifunctional catalyst. Many research groups are developing new mesoporous materials that have applications as catalysts, adsorbents, or catalyst supports that minimize the deposition of carbon on surface of catalyst and increase the conversion of ethylbenzene as well as styrene selectivity. Burri et al. 17 reported the influence of SBA-15 support on CeO 2 -ZrO 2 catalyst for the dehydrogenation of ethylbenzene to styrene under CO 2 flow. Liu et al. 18 have investigated