Development of non-petroleum feedstocks: The role of catalysis.

摘要

The utilization of natural gas and coal feedstocks was initiated in the 1970s' in response to volatility in availability and price of petroleum. This concerted effort led to the development of processes based on C(sub 1), chemistry (2) through which synthesis gas (a mixture of CO and H(sub 2)) could be catalytically converted to hydrocarbons and oxygenates. The catalytic conversion to hydrocarbons via the Fischer-Tropsch (F-T) reaction continues to be of commercial interest (1) but further improvements in reaction rates and product selectivity are sought. To this effect, recently a liquid phase Fe (slurry) F-T catalyst has replaced the traditional solid Fe. For oxygenates synthesis the utilization of organometallic complexes is established. Examples include homogeneously catalyzed commercial synthesis of acetic acid (Monsanto process) and acetic anhydride (Eastman Kodak process) catalyzed presumably by Rh(CO)(sub 2)I(sub 2)(sup (minus)) species at (approximately)180(degrees)C and (degrees)50 atm. These examples indicate that organometallic complexes will find increasing applications as catalysts in new and improved processes. Since economical processes for direct conversions of coal (direct liquefaction) and natural gas (direct methane conversion) are yet to be targeted for commercial applications, synthesis of oxygenates via the ''Indirect Route,'' i.e. through synthesis gas, is carried out. The stoichiometry of synthesis gas produced from these two sources is of interest. Thus, the H(sub 2)/CO ratio varies from < 1 for coal-derived syngas to 3 for syngas from steam-reforming of natural gas. In order to maximize C utilization, the Catalyst-By-Design (CBD) approach for synthesis of methanol and higher oxygenates is ongoing under the ''BNL Catalyst Development'' program.