Catalytic Performance of Chromium Oxide Supported on Al₂O₃ in Oxidative Dehydrogenation of Isobutane to Isobutene

Abstract

In this study, the performance of chromium oxide catalysts supported on Al 2 O 3 was evaluated. The effects of the percent loading of Cr on Al 2 O 3 and the pretreatment conditions on the activity and the selectivity of the catalysts in the oxidative dehydrogenation of i-C 4 H 10 to i-C 4 H 8 were also tested. Different types of Al 2 O 3 were tested as supports for chromium oxide, and the activity and selectivity of these samples were correlated with the alumina properties. The obtained results show that the optimum loading of Cr on Al 2 O 3 lies between 5 and 15%. Also, it has been observed that the calcination temperature affects the conversion at lower reaction temperatures, whereas its influence on product selectivity is limited by O 2 availability in the reaction mixture. The catalyst samples were characterized by FTIR and XPS measurements. The XPS analysis confirmed the presence of Cr 6+ and Cr 3+ on the surface of the catalyst. Cr 3+ was dominant in the spent catalyst.

Behavior of active sites on Cr-MCM-41 catalysts during the dehydrogenation of propane with CO2

“…The reaction is endothermic and inevitably controlled by the thermodynamic equilibrium, requiring substantial energy consumption. Supported chromium oxides have also been investigated for the oxidative dehydrogenation of lower alkanes [5][6][7][8][9][10][11] or oxidation of other organic compounds with oxygen [12,13]. However, the use of oxygen as an oxidant is frequently accompanied by deep oxidation, resulting in a decrease in product selectivity.…”

CrHZSM-5 Zeolites – Highly Efficient Catalysts for Catalytic Cracking of Isobutane to Produce Light Olefins

“…The utilization of C4 in chemical industry was mainly olefins, and C4 alkanes were primarily used as fuel. Isobutane was one of the main components of C4 alkanes which is often used for alkylation reaction to produce high octane number gasoline [7,8], and dehydrogenation to produce isobutene [9][10][11].…”

Oxidative Dehydrogenation of Propane over Supported Chromia Catalysts: Influence of Oxide Supports and Chromia Loading

“…Supported chromia catalysts have also been successfully studied for dehydrogenation and oxidative dehydrogenation reactions (11)(12)(13)(14)(15). For example, Grzybowska et al (16) and Al-Zahrani et al (17) studied the influence of chromia loading and preparation methods on the structurereactivity properties of Cr 2 O 3 /Al 2 O 3 catalysts for the ODH of isobutane. They observed an optimum chromium loading on Al 2 O 3 (surface area = 245 m 2 /g) between 5 and 15 wt% of Cr 2 O 3 , where the ODH activity was the highest.…”