Rapid scan FTIR reveals propane (am)oxidation mechanisms over vanadium based catalysts

Abstract

Rapid scan FTIR coupled with Mass Spectrometry (MS) has been used to determine the role of spectroscopically observed species in the reaction media during propane dehydrogenation over a V/Al catalyst, and propane ammoxidation on a Sb-V-O sample. During the propane dehydrogenation reaction, it was shown that oxygenates are not formed during the first minutes and propylene is formed directly from propane via dehydrogenation on a V-O site. Oxygenates may form though secondary reactions due to further propylene oxidation. Propane dehydrogenation is the first step during the propane ammoxidation reaction. This is followed by the transformation of propylene into acrylonitrile, which is the rate limiting step. Rapid scan FTIR/MS is shown to be a useful technique for monitoring chemical reactions in order to identify or eliminate observed surface species as potential reaction intermediates. Understanding of the reaction mechanism is necessary in order to improve the chemical process design and the catalytic material.

Photothermal Propane Dehydrogenation Catalyzed by VOx-Doped TiO2 Nanoparticles

“…The bands at 2919 and 2974 cm −1 in Figure 7c could be ascribed to C 3 H 8 adsorption. 36 When light was introduced, 2919 and 2974 cm −1 bands disappeared quickly. It demonstrates the fast conversion of the adsorbed C 3 H 8 .…”

Light hydrocarbon conversion to acrylonitrile and acetonitrile – a review

“…Guerrero-Pérez et al used a rapid-scan FTIR equipped with a mass spectrometer to elucidate the mechanism of propane ammoxidation and oxidation reactions. 66 They found that the oxygenates were not formed at the outset of the reaction. They stated that propylene promptly evolved from propane, and oxygenates may be produced by the subsequent reactions (e.g., propylene ammoxidation to AN).…”