The design of methane activation catalysts

The goal of Sandia's methane activation program is to use computer-aided-design (CAD) techniques to guide the synthesis of catalysts for the direct conversion of methane. Several enzymes, such as cytochrome P/sub 450/ and methane monooxygenase, catalyze the oxidation of alkanes to alcohols at low temperatures and pressures. we are attempting to design catalysts that mimic these enzymes. Our CAD studies on porphyrins, which are the active sites in many enzymes, are being combined with 1) structural characterization of naturally occuring catalysts; 2) the development of activity and selectivity tests; and 3) the synthesis and characterization of designed catalysts. Results of CAD studies on enzymes that carry out alkane activation or perform C/sub 1/ chemistry and on unique synthetic porphyrins have shown that the synthetic porphyrins can have site configurations analogous to these enzymes. The CAD work also uses molecular-energy minimization and dynamics calculations to evaluate methane interactions with the synthetic porphyrins. Activity tests have been set up for cyclohexane, hexane and butane with additional tests being developed for methane and ethane. Synthesis of designed porphyrins is currently underway. 9 refs., 4 figs.