Methanol synthesis via methylformate in a slurry reactor

The synthesis of methanol from CO and H2 using a reaction sequence in which methanol is first carbonylated to methylformate and then hydrogenated to methanol was studied. The reaction occurred concurrently in a single mechanically agitated slurry reactor using the usual homogeneous formate synthesis catalyst (CH3OK) and a heterogeneous catalyst (copper-chromite) at temperatures of 140 to 180°C and pressures of 38 to 62 bar. The concurrent operation is not a simple summation of the two individual reactions. It is likely that the CH3OK is adsorbed on the copper-chromite. The rate of formation of methanol is significantly higher than predicted from the individual reactions and the deleterious effect of CO2 on the CH3OK catalyzed carbonylation of methanol and on the hydrogenolysis of methyl formate is reversible. The carbonylation reaction is in equilibrium under the conditions studied. A progressive reduction in reaction rate with time was found and is attributed to the effect of CO on the hydrogenolysis catalyst. Comparisons are made of the concurrent methanol synthesis in a slurry reactor with alternative methods of methanol synthesis.