Role of Cobalt Oxide-Based Catalysts for Styrene Production: A Review on Significance of Various Promoters, Calcination Temperature, Chemical Behavior of Support Materials and Synthesis Procedure

The direct CO2 oxidative dehydrogenation of ethyl benzene (ODH-EB) is a great potential for the production of valuable styrene monomer. In contrast, past/present styrene (ST) synthesis is mainly obtained from oxidative dehydrogenation of ethyl benzene (EB) and being transformed into pilot scale under CO2 atmosphere. It was due to few unresolved restrictions existed in the synthesis of styrene monomer using the steam assisted process and commercial ST production technology. These problems are being rectified by ODH-EB process using CO2 as a soft oxidant. Therefore, ODH of EB is well-known high temperature process to convert the EB (petroleum by product) into valuable ST monomer through the utilizing of CO2. Present study clearly explains the concise history of dehydrogenation process used to convert EB to ST monomer, which is essential feedstock in the wide range of industrial commodities production. In this discussion we majorly devoted to design, development and synthesis of different Co based catalysts by applying different support materials such as SiO2, MgO, MgAl2O4 and gamma-Al2O3 respectively. Moreover, this study extensively deals with chemical behavior of oxidants, utilization of viable active promoters and its characteristics features in the oxidative dehydrogenation process. Different reaction mechanisms in the ODH of EB process to describe CO2 utilization as well as surface styrene monomer formation and evaluation of other by products were discussed widely in this review paper. The surface acidic and basic chemistry of various support materials, its preparation, utilization and its catalytic activity applications have been discussed. Acidic-basic textural properties of different solid oxide support materials have been extensively illustrated through incorporation of variety active metallic oxide and promoters. The catalyst activity evaluation in ODH of EB process as well as plausible reaction mechanism of styrene monomer formation has been explained.