Dehydrogenation Of Ethane With Carbon Dioxide To Ethene

The processes of catalytic conversion of alkanes into their corresponding alkenes by oxidative or nonoxidative dehydrogenation are of increasing importance because of growing demand for alkenes. Ethane is an abundant component in natural gas; however, its utilization in these processes receives the least attention due to the existence of traditional thermal cracking process. The oxidative dehydrogenation of ethane by oxygen into ethylene has been proposed as an alternative to the process of thermal cracking of ethane because it possesses several advantages, such as lower reaction temperature operation and less catalyst deactivation due to coking. Carbon dioxide as one of the major greenhouse gases has recently been considered as a source of carbon. In fact, carbon dioxide can also act as a mild oxidant. Utilization of carbon dioxide in some partial oxidation reactions, such as CO₂ reforming of methane, oxidative coupling of methane, and oxidative dehydrogenations of ethane, propane, and isobutane, has been reported. In this investigation, several supported Co, Cr oxide and cobalt-substituted MCM-41 catalysts were prepared and their catalytic behavior in the oxidative dehydrogenation of ethane with carbon dioxide over these catalysts, were studied. Supported chromium and cobalt oxides are well known to be active catalysts for dehydrogenation of alkanes. Firstly, a series of Co-Cr/SiO₂ and Co-Cr/Al₂O₃ catalysts with different Co/Cr ratios was prepared by impregnation method. We investigated the catalytic activity of these catalysts in the oxidative dehydrogenation of ethane, and found that these catalyst systems showed high selectivity to ethylene but low conversion of ethane and carbon dioxide. 1%Co-5%Cr/ Al₂O₃ was found to be the best catalyst for the topic reaction. At 973K, the conversion of C₂H₆ and CO₂ were 25.57% and 13.72% respectively; the selectivity of C₂H₄ was 94.28%. The effects of...