Targeted synthesis of a copper catalyst with a nanostructured active component

Abstract

The effect of the hydrodynamic regime in the stirring of a copper carbonate–ammonia suspension containing an alumina–silica support on the chemical and phase composition of an active component (AC) precursor for a catalyst of cyclohexanol dehydrogenation to cyclohexanone is studied. By means of X-ray diffraction, differential thermal analysis, and adsorption, the precursor is found to precipitate in a developed turbulent regime, predominantly in the form of nanostructured hydroxocarbonate structures strongly bonded to the support. Some catalytic and textural properties of CAS-C (copper–alumina–silica for caprolactam) samples are studied with AC contents of 20 to 30 wt % (on a copper oxide basis). The laboratory technology is scaled up to industrial conditions. CAS-C samples and commercial H3-11 catalyst (BASF) are subjected to catalytic tests (in a flow-type reactor with a fixed catalyst bed 40 cm³ in volume at a temperature of 250°C and atmospheric pressure). The CAS-C catalyst is shown to be similar to the H3-11 catalyst in terms of selectivity, and to considerably surpass it in activity and thermal stability.