METHANOL SYNTHESIS CATALYSTS DERIVED FROM COPPER INTERMETALLIC PRECURSORS - TRANSIENT-RESPONSE TO PULSES OF CARBON-DIOXIDE, OXYGEN AND NITROUS-OXIDE

The transient response of alloy-derived catalysts for the synthesis of methanol upon exposure to pulses of oxidizing gases (CO2, O2, N2O) has been investigated. The catalysts were prepared by in situ activation of copper/rare earth (RE) binary alloys and ternary alloys [(Cu-RE(x)-M(y)): M = Bi, Zr] in the CO/H-2 process gas. In all cases, pulsed injection of the oxidant led to a significant transient increase in the exit methanol concentration with the effectiveness decreasing in the order O2 greater-than-or-similar-to N2O > CO2. No deactivation was evident upon repeated pulsing even though, in the case of CO2, time averaged levels of the oxidant were such that they would cause a strong poisoning effect if present in the form of a continuous feed. An oxidative displacement of preformed methanol (or a direct precursor) from the catalyst surface is proposed to account for these observations.