The effect of MgO and preparation techniques of the FeMnO_δ/MgO–Al₂O₃ catalyst used for the vapor phase oxidation of cyclohexane

Abstract

Magnesia modified alumina with varying content of MgO was synthesized by impregnation technique and used as support for the synthesis of supported Iron-Manganese oxide catalysts. The effect of synthesis technique...

Spectroscopic and Kinetic Study of Cyclohexane Oxidation Reaction in Vapor Phase over the Catalyst 20FeMnOδ/(3CeAl)

“…The XRD patterns revealed the diffraction peaks (2θ) at 19.5°, 32.7°, 37.2°, 39.5°, 46°, 60.5°, 67°, and 85°, which corresponded to the crystalline phase of γ-Al 2 O 3 . 11,36 The incorporation of 3 wt % of ceria resulted in the formation of a new phase AlCeO 3 (JCPDS 98−011−7997) which was confirmed by the diffraction peaks at 33°, 47.5°, 56.5°, 77°, and 79.5°. Additionally, the diffraction peaks at 28.7°, 47°, and 56.5°were attributed to the presence of CeO 2 in the catalyst.…”

“…46 All the reduction peaks are described in detail elsewhere. 11 The addition of ceria-promoted catalysts resulted in the ease of reducibility of various oxides on the surface of the catalysts.…”

“…In situ diffuse reflectance Fourier transform spectroscopy (DRIFTS) analysis is a widely used technology to establish a direct relationship between the structure of the catalyst and its performances by diffuse reflectance of IR radiations through the catalyst’s particles and collecting valuable information such as nature, the evolution of new surface species and its concentration, and adsorption geometry of the reactants, products, intermediate, and spectator species adsorbed on to the surface during the reactive environment. − The in situ DRIFTS is used to investigate the adsorbed methanol in partial methane oxidation, surface characteristics of catalysts MoVTeO and MoVTeNbO, and their catalytic behavior . Furthermore, the spectroscopic study is used to find the surface-adsorbed species in determining the type of oxy-functional groups, reaction pathways, and reaction kinetics approaches for the selective photo-oxidation of cyclohexane. ,,− …”

“…It is reported that the oxidation of Cy-H in the vapor phase passed through the formation of cyclohexanolate as an intermediate species. 10,11 However, its functional chemistry remains poorly understood for vapor phase cyclohexane oxidation in a heterogeneous catalytic environment. Kinetics for various reactions in heterogeneous catalysis based on heterogeneous catalytic models such as Langmuir−Hinshelwood-Hougen-Watson (LHHW) and Eley−Rideal (ER) have been reported.…”

“…Therefore, attention has been paid to the continuous production of KA oils via vapor phase cyclohexane oxidation at low pressure to meet the increasing demand for KA oils. Supported mixed metal oxide catalysts have shown better performance in the oxidation of hydrocarbons. − High conversion of cyclohexane with more than 80% selectivity of desired products using various catalysts, such as Ce–Mn 7 , CeAlPO5, 13X zeolite supported cobalt oxide, ceria nanocomposite supported on graphene oxides, mixed oxides of Fe–Mn supported on alumina, and MgO modified alumina, in vapor phase cyclohexane oxidation have been reported so far. The ceria-promoted alumina is also a good choice as a catalyst support, enhancing the percent conversion and product selectivity of various reactions.…”