Some Zn-Cr-O-based catalysts for the synthesis of methylpyrazine from ethylenediamine and propylene glycol were prepared through the sol-gel technique, from aqueous nitrates and polyacrylic acid. The oxide mixtures so obtained were analysed by several techniques, including scanning electron microscopy, electron probe microanalysis, X-ray diffraction, electron spin resonance (ESR), sorption-desorption of nitrogen, etc. The catalytic activity was tested by the pulse-reactor technique and with a temperature-programmed desorption-reaction apparatus. All the data were compared with those previously collected on similar catalysts prepared either by the wet-mixing procedure or by coprecipitation. It was found that the structure of the solid depends strongly on the method of preparation, besides the chemical composition. The selectivity to the desired product peaked for Zn/Cr=3 and the smaller the crystal size of the powder, the better the catalyst was found to perform. The ESR signal generated by the Cr3+ ions may constitute a useful tool for monitoring both the intimate structure and the catalytic behaviour of the material.
|Titolo:||Structural analysis and catalytic activity of sol-gel-prepared Zn-Cr-O|
FORNI, LUCIO (Primo)
OLIVA, CESARE (Secondo)
|Settore Scientifico Disciplinare:||Settore CHIM/02 - Chimica Fisica|
|Data di pubblicazione:||1993|
|Digital Object Identifier (DOI):||http://dx.doi.org/10.1007/BF00354249|
|Appare nelle tipologie:||01 - Articolo su periodico|