| Popis: |
Summary Thermography, EPR, IR spectroscopy and some other pertinent methods were applied to study various stages of the preparation process for a promoted chromium-zinc-manganese catalyst characterized by a high activity and selectivity with respect to vapour-phase aldehyde decarbonylation reactions. The catalyst preparation process comprises several stages, such as co-precipitation of zinc and manganese chromates, introduction of a promoting additive, pelletization, and reduction. The spinel structure is formed in the course of thermal treatment and hydrogen reduction. Alkali metal cations act as promotors, whereas adding aluminia and water leads to a higher mechanical strength of the pelletized catalyst. A commercial technology has been developed to manufacture the catalyst which has found an extensive practical use in a number of industrial processes. |
