Thermodynamic Analysis of Indirect Ethanol Synthesis from Syngas

The dependence of chemical equilibrium constant on the reaction temperature and pressure and the feed molar ratio were theoretically calculated for indirect ethanol synthesis from syngas through the coupling of CO with methyl nitrite (MN) to dimethyl oxalate (DMO) and the hydrogenation of DMO to ethanol. It shows that the coupling process and the hydrogenation of DMO to ethanol are highly favorable at all temperatures and pressures, especially at low temperature. The hydrogenation of DMO to ethylene glycol (EG) and the further reaction of ethanol with H2 to high alcohol are thermodynamically favorable at low temperatures, below 630 and 450 K, respectively. Additionally, high reaction pressure is facilitated to EG and high alcohol formation. Accordingly, moderate reaction temperature (up 538 K) and low reaction pressure (below 1 MPa) are beneficial to ethanol production.