Ethane to aromatic hydrocarbons: Past, present, future

Ranking high in the current challenges of catalysis, direct transformations of lower lower saturated hydrocarbons (alkanes) have been investigated for a long time. However, unsaturated hydrocarbons (e.g., aromatics and olefin s) have always been the more important feedstocks to produce basic and inte rmediate chemicals because of their wide variety of possible reaction pathw ays. This article focuses on the conversion of one representative of lower alkanes-ethane, which is an important constituent of natural gas, accompany ing gases and waste effluents of petrochemical processes-to aromatic compou nds. Following general considerations on the aromatization of ethane, efficient modification methods of MFI-type zeolites to obtain active and selective ca talysts will be presented. The nature of active sites, including the promot ing effects of zinc, gallium,or noble metals, will be discussed. Single pat hways in the reaction network from ethane toward aromatic hydrocarbons are explored based on experiments under steady-state and transient-state condit ions. Finally, an outlook for possible transformations of the fundamental k nowledge to full-scale industrial application will be given.