Selective Catalytic Synthesis of Branched C4-C7 Hydrocarbons by Low Temperature C1 Homologation Reactions over Medium and Large Pore Acidic Zeolites: A Mechanistic Study Aditya Bhan, University of Minnesota, Twin Cities The synthesis of larger hydrocarbons from C1 pre-cursors will have far reaching implications for the use of non-traditional carbon based feedstock such as coal, natural gas, and biomass for supplying the planet with energy carriers and other substitutes for petroleum products. The conversion of methanol-to-hydrocarbons (MTH) over zeolite catalysts represents the final step in upgrading any gasifiable feedstock to gasoline-range hydrocarbons. The active site in MTH catalysis is an organic-inorganic hybrid reaction center consisting of the inorganic zeolite and an entrapped organic compound that enables C-C bond formation reactions. Therefore, the catalytic behavior of MTH systems is determined not only by the structural and composition features of the inorganic molecular sieve but also by the organic co-catalyst that comprises the “hydrocarbon pool”. We show that by systematically manipulating the olefin and arene content of the hydrocarbon pool in MTH catalysis, we can control the selectivity of C-C bond formation reactions in MTH catalysis. Our results highlight the seminal role the organic co-catalyst plays in MTH chemistry and demonstrates a novel Methodology to control selectivity in MTH catalysis. Instead of changing the inorganic zeolite catalyst, we can “seed” the hydrocarbon pool by co-feeding olefin and aromatic compounds to tune selectivity