Thermodynamic Analysis of CO₂Hydrogenation to Higher Alcohols (C_2-4OH): Effects of Isomers and Methane

Synthesis of higher alcohols (C2-4OH) by CO2 hydrogenation presents a promising way to convert CO2 into value-added fuels and chemicals. Understanding the thermodynamics of CO2 hydrogenation is of great importance to tailor the reaction network toward synthesis of higher alcohols; however, the thermodynamic effects of various alcohol isomers and methane in the reaction system have not yet been fully understood. Thus, we used Aspen Plus to perform thermodynamic analysis of CO2 hydrogenation to higher alcohols, studying the effects of alcohol isomers and methane. Thermodynamically, methane is the most favorable product in a reaction system containing CO, CO2, and H2, as well as C1-4 alkanes, alkenes, and alcohols. The thermodynamic favorability of alcohol isomers varies significantly. The presence of methane generally deteriorates the formation of higher alcohols. However, low temperature, high pressure, high H2/ CO2 ratio, and formation of alcohols with a longer carbon chain can reduce the effects of methane. Our current study, therefore, provides new insights for enhancing the synthesis of higher alcohols by CO2 hydrogenation.