Chapter 5. Catalytic conversion of syngas to i-butanol – Synthesis routes and catalyst developments: A review

Abstract

The interest in converting synthesis gas to alcohols and oxygenated fuel additives is growing rapidly due to the increasing demand for the compounds and the currently low cost of syngas from sources such as coal and natural gas. Among the potential end products, C2+ alcohols are desirable since they serve as clean alternative fuels, gasoline blends, and hydrogen carriers to supply fuel cells. There are a number of literature reports that focus on the synthesis of ethanol from syngas. However, compared to ethanol, C3+ alcohols may have wider use as gasoline substitutes due to their higher energy density, lower hygroscopicity and lower volatility. In addition, branched-chain alcohols (such as isobutanol) have higher octane numbers than their straight-chain linear counterparts. However, there are very few literature reports focusing on the synthesis of alcohols higher than ethanol. Hence this review focuses on the synthesis of higher alcohols, particularly isobutanol, by addressing current synthesis methods, thermodynamics of syngas conversion to these oxygenates, catalytic reaction mechanisms, catalysts, and future directions, which could serve as building blocks for further research in this area.