Growing the Bioeconomy through Catalysis: A Review of Recent Advancements in the Production of Fuels and Chemicals from Syngas-Derived Oxygenates

Synthesis gas (syngas), composed primarily of H2 and CO, can be produced from fossil resources, municipal solid waste, biogas, and terrestrial biomass and can be converted into oxygenated intermediates such as alcohols and aldehydes through both catalytic and biological routes. These oxygenates serve as precursors for the downstream production of fuels and chemicals. However, since these processes all proceed through syngas regardless of the feedstock, renewable resources do not offer any inherent chemical advantage over fossil resources, and the process economics is largely dictated by (i) the spread between feedstock cost and the cost of petroleum (the dominant existing feedstock for fuel and chemical production) and (ii) the conversion efficiency, in terms of both energy and carbon, normalized by capital costs. Thus, lower-cost renewable feedstocks and improved conversion efficiencies combined with policy incentives could enable increased incorporation of biocontent into fuels and chemicals through syngas-derived oxygenates. To that end, this review assesses recent advancements in heterogeneous catalysis for the downstream conversion of syngas-derived oxygenates (i.e., methanol, ethanol/C2+ alcohols, and aldehydes) to fuels and chemicals, specifically seeking to link how these advancements improve the overall conversion efficiency. In the long term, these catalysis advancements can expand the window of market conditions over which these syngas pathways are economically viable, creating an opportunity to "piggyback" on existing and future natural gas to liquids installations by cofeeding renewable feedstocks.