Selective Oxidation of 5-Hydroxymethylfurfural to 2,5-Furandicarboxylic Acid Using O 2 and a Photocatalyst of Co-thioporphyrazine Bonded to g-C 3 N 4

作者：Shuai Xu, Peng Zhou, Zehui Zhang, Changjun Yang, Bingguang Zhang, Kejian Deng, Steven E. Bottle, Huaiyong Zhu · 发表于：Journal of the American Chemical Society · 年份：2017 · DOI：10.1021/jacs.7b08861 · 被引用次数：449 · 研究领域：Polyoxometalates: Synthesis and Applications、Catalysis for Biomass Conversion、Electrocatalysts for Energy Conversion

Selective oxidation of 5-hydroxymethylfurfural (HMF) to 2,5-furandicarboxylic acid (FDCA) is one of the key reactions for producing chemical commodities from biomass and their derivatives. The challenge for this reaction is to develop an efficient catalytic process that can be conducted under mild conditions (room temperature and atmospheric pressure, using oxygen molecules in air as the oxidant) and a recyclable catalyst. Herein we report a photocatalyst of cobalt thioporphyrazine (CoPz) dispersed on g-C 3 N 4 (abbreviated as CoPz/g-C 3 N 4 ), which exhibits excellent catalytic activity toward the selective oxidation of HMF into FDCA under simulated sunlight using oxygen molecules in air as a benign oxidant. For example, an FDCA yield of 96.1% in an aqueous solution at pH = 9.18 is achieved at ambient temperature and air pressure. At lower pH (4.01), the product generated is 2,5-diformylfuran. Hence, it is possible to control the reaction outcome by control of the pH of the reaction system. g-C 3 N 4 itself is not a suitable catalyst for the selective oxidation because under the experimental conditions g-C 3 N 4 generates hydroxyl radicals that initiate processes that oxidize HMF directly to CO 2 and H 2 O. CoPz on the other hand activates O 2 to give singlet oxygen ( 1 O 2 ), which more controllably oxidizes HMF to FDCA albeit at a more moderate yield (36.2%). The strong interaction between the CoPz and g-C 3 N 4 in the CoPz/g-C 3 N 4 catalyst is experimentally evidenced, w...