Cerium Containing Siliceous MCM-22: Preparation, Characterization and its Potential Application towards Oxidation of Isoeugenol to Vanillin

Abstract

Aim: Preparation of cerium containing silicious MCM-22 zeolite material and explore its application for biomass conversion. Background: Zeolites and zeolite like microporous materials are well known as potential heterogeneous acid catalysts, whose discovery has made a significant impact in the petroleum, petrochemical and fine chemical industries. In recent years, zeolite, zeolites like molecular sieves, and inorganic oxide-based heterogeneous catalysts played a significant role in biomass valorization to receive value-added chemicals. Thus we focused on utilization of zeolite for biomass transformation. Objective: Preparation of cerium containing aluminium-free siliceous MCM-22 (AF-CeMCM- 22) by the in-situ hydrothermal method and explore its importance on biomass transformation. Methods: Powder XRD, FTIR and BET surface area were used to study the microstructure of the samples. SEM and FE-SEM were used to study morphology, TGA was used to evaluate the thermal stability, and 29Si NMR and DR-UV-Vis were used to study the environment of the MCM-22 framework. The prepared and confirmed material was used for the oxidation of levulinic acid over the liquid phase setup. Gas chromatography was used to evaluate the catalytic study, such as conversion and selectivity; also, GCMS was used for the confirmation of products. Results: The powder XRD pattern showed well distinguish MCM-22 framework structure with a uniform dispersion of cerium ions in the MCM-22 framework. SEM image of the cerium AFCeMCM- 22 showed platelet structure having flaky spherical morphology and the surface area in the range of about 175 m2g−1. 29Si NMR and DR-UV-Vis studies confirmed the well-condensed nature of the MCM-22 silica framework and the cerium ions present in both tetrahedral and octahedral extra-framework environments. Conclusion: The catalyst developed in the present studies was found to be a promising catalyst for the conversion of iso-eugenol to vanillin at 60°C, using H2O2 oxidant with the vanillin selectivity of 71 %.