Modification by SiO2 of Alumina Support for Light Alkane Dehydrogenation Catalysts

Abstract

Due to the continuously rising demand for C 3 -C 5 olefins it is important to improve the performance of catalysts for dehydrogenation of light alkanes. In this work the effect of modification by SiO 2 on the properties of the alumina support and the chromia-alumina catalyst was studied. SiO 2 was introduced by impregnation of the support with a silica sol. To characterize the supports and the catalysts the following techniques were used: low-temperature nitrogen adsorption; IR-spectroscopy; magic angle spinning 29 Si nuclear magnetic resonance; temperature programmed desorption and reduction; UV-Vis-, Raman-and electron paramagnetic resonance (EPR)-spectroscopy. It was shown that the modifier in amounts of 2.5-7.5 wt % distributed on the support surface in the form of SiO x -islands diminishes the interaction between the alumina support and the chromate ions (precursor of the active component). As a result, polychromates are the compounds predominantly stabilized on the surface of the modified support; under thermal activation of the catalyst and are reduced to the amorphous Cr 2 O 3 . This in turn leads to an increase in the activity of the catalyst in the dehydrogenation of isobutane.

Pd-membrane Integration in a Propane Dehydrogenation Process for Highly Selective Propylene Production

“…The critical issue is catalyst deactivation; research is mainly focused on finding more stable formulations starting from chromium-and platinum-based catalysts that are the most commercially used in industrial processes [6]. Surely, Pt-based catalyst arouses more interest not only for its eco-friendly properties but also for its higher catalytic performances: it is able to activate easier C-H bonds than C-C in PDH reaction [7].…”