CO-Free Methyl Formate from Methanol: the Control of the Selectivity of the Process on Cu-Based Catalysts
T. P. Minyukova, N. V. Shtertser, L. P. Davydova, I. I. Simentsova, A. V. Khasin and T. M. Yurieva
G. K. Boreskov Institute of Catalysis, Siberian Branch of the Russian Academy of Sciences,
Pr. Akademika Lavrentyeva 5, Novosibirsk 630090 (Russia), E-mail: min@catalysis.nsk.su
Страницы: 189-196
Аннотация
The influence of the structure and composition of precursor (which is used as support after treatment) and the structure of copper particles formed in the course of activation of copper containing catalysts by hydrogen on their catalytic properties in methanol dehydrogenation and reactivity towards hydrogen adsorption has been studied. The reactivity of catalyst towards hydrogen adsorption was investigated by means of Thermal Desorption Spectroscopy (TDS). Two catalysts preserving the structure of their precursor-oxide after reduction (CuZnSi and CuCr) and having strong bonds of metal particles with the surface are characterized by hydrogen adsorption at elevated temperatures. This type of adsorption is not observed for usual unsupported metal copper and for two other catalysts Cu/SiO2 and Cu/Cr2O3. Methanol dehydrogenation proceeds via successive reactions 2CH3OH = CH3OOCH + 2H2 (I) and CH3OOCH = 2CO + 2H2 (II). The catalyst activity in reaction (II) greatly depends on the state of metal copper in the catalyst. It was assumed that catalyst activity in methyl-formate conversion to CO and H2 and, hence, the selectivity of methanol dehydrogenation in respect to methylformate at moderate methanol conversion depends on the character of interaction between metal copper particles and catalyst oxide surface, which is determined by the composition and structure of oxide precursor.
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