Production of methanol and isobutyl alcohol mixtures over double-bed cesium-promoted Cu/ZnO/Cr2O3 and ZnO/Cr2O3 catalysts

Utilization of a Cs-promoted Cu/ZnO/Cr2O3 catalyst as a first low-temperature bed and a Cs-promoted ZnO/Cr2O3 catalyst as a second high-temperature bed significantly promoted the productivity of 2-methyl-1-propanol (isobutyl alcohol) from H-2/CO synthesis gas mixtures. While the conversion of CO to C-2+ oxygenates over the double-bed configuration was comparable to that observed over the single Cu-based catalyst, major changes in the product distribution occurred by the coupling to the zinc chromite catalyst; i.e., the productivity of the C-1-C-3 alcohols decreased dramatically and 2-methyl-branched alcohols were selectively formed. The desirable methanol/2-methyl oxygenates molar ratios close to 1 were obtained in the present double-bed system that provide the feedstock for the synthesis of high octane and high cetane ethers.