The Preparation of the Catalysts for Methanol Synthesis and their Characteristics

Abstract

The compacting pressure to form a tablet up to 10 ton/cm 2 affected the greater pore size distributions than 200 Å of ZnO-Cr 2 O 3 catalyst to shift to smaller radii and this caused the reduction in the catalytic activity for CO shift conversion. The ZnO-Cr 2 O 3 - CuO catalyst has shown a markedly promoted catalytic activity for methanol synthesis even in a very small addition of copper. The optimum atomic ratio of Zn: Cr: Cu for both reactions was 1: 1: 0.3 and 1: 1: 1-2, respectively. According to the X-ray powder diffraction diagram a Cr-Cu compound disappeared in the drying step before reduction and zinc chromite was found together with excess zinc oxide and copper after use in the reaction. The Cu-ZnO-Al 2 O 3 catalyst, dependent upon the copper content with the optimum atomic ratio of Cu: Zn: Al = 1: 0.6: 0.08, exhibited a high catalytic activity at a lower reaction pressure, as generally known. It was suggested that metallic copper plays a dominating part in the catalytic activity. The mechanical strength of ZnO-Cr 2 O 3 -CuO catalyst before and after reduction depends upon the water content, in the latter case being appreciably lower. The different contribution of copper to the catalytic activity and the mechanical strength was suggested in consideration of the surface properties.