Direct Conversion of Renewable CO<sub>2</sub>-Rich Syngas to High-Octane Hydrocarbons in a Single Reactor
Claire T. Nimlos, Connor P. Nash, Daniel P. Dupuis, Anh T. To, Anurag Kumar, Jesse E. Hensley, Daniel A. Ruddy
Abstract
The synthesis of branched hydrocarbons for high-octane gasoline and sustainable aviation fuel directly from CO2-rich syngas in a single reactor holds potential to decrease capital and operating costs and increase overall energy and carbon efficiencies in a biorefinery. Here, we report the cascade chemistry of syngas to hydrocarbons under mild reaction conditions in a single reactor with C4+ single-pass yields of 13.7–44.9%, depending on the relative catalyst composition employing our dimethyl ether homologation catalyst, Cu/BEA zeolite. With co-fed CO2 at a concentration representative of biomass-derived syngas, 2.5:1:0.9 for H2:CO:CO2, a hydrocarbon yield of 12.2% was observed with similar selectivity to C4+ products compared to the CO2-free feed. Definitive evidence of CO2 incorporation into the hydrocarbon products was demonstrated with isotopically labeled 13CO2 co-feed experiments, where mass spectrometry confirmed the propagation of 13C into the C4+ hydrocarbons, highlighting the feasibility to co-convert CO and CO2 in this single reactor approach.