Imidazolized Activated Carbon Anchoring Phosphotungstic Acid as a Recyclable Catalyst for Oxidation of Alcohols With Aqueous Hydrogen Peroxide

Min Zheng; Huiting He; Xiangzhou Li; Dulin Yin

doi:10.3389/fchem.2022.925622

Imidazolized Activated Carbon Anchoring Phosphotungstic Acid as a Recyclable Catalyst for Oxidation of Alcohols With Aqueous Hydrogen Peroxide

Front Chem. 2022 Jun 29:10:925622. doi: 10.3389/fchem.2022.925622. eCollection 2022.

Authors

Min Zheng^{1

2}, Huiting He³, Xiangzhou Li¹, Dulin Yin³

Affiliations

¹ College of Material Science and Engineering, Central South University of Forestry and Technology, Changsha, China.
² College of Physics and Chemistry, Hunan First Normal University, Changsha, China.
³ National & Local Joint Engineering Laboratory for New Petro-chemical Materials and Fine Utilization of Resources, College of Chemistry and Chemical Engineering, Hunan Normal University, Changsha, China.

Abstract

Keggin-type phosphotungstic acid (HPW) supported on imidazolyl-activated carbon (AC-COIMI-HPW) catalysts was prepared, which was used to catalyze the oxidation of benzyl alcohol with aqueous H₂O₂. In the presence of AC-COIMI-HPW, the benzyl alcohol conversion of 90.2% with 91.8% selectivity of benzaldehyde was obtained at 90°C for 6 h in an acetonitrile aqueous solution. The catalyst exhibited an outstanding performance for the oxidation of various benzyl alcohols and aliphatic alcohols. In addition, the catalyst could be easily recovered and reused five times without significant deactivation. The characterization results showed that HPW was chemically bonded on the surface of the carbon material through an ionic bond. It is proposed that the combination of the imidazole cation with the HPW anion could not only tune the redox catalytic properties of the PW anion but also enhance the compatibility of the catalyst in the reaction medium, thereby improving the catalytic performance.

Keywords: 2-methylimidazole; activated carbon; benzyl alcohol; oxidation; phosphotungstic acid.