Vicinal hydroxyl group-inspired selective oxidation of glycerol to glyceric acid on hydroxyapatite supported Pd catalyst

作     者：Difan Li Xiuge Zhao Qingqing Zhou Bingjie Ding Anna Zheng Qingpo Peng Zhenshan Hou Difan Li;Xiuge Zhao;Qingqing Zhou;Bingjie Ding;Anna Zheng;Qingpo Peng;Zhenshan Hou

作者机构：Key Laboratory for Advanced MaterialsResearch Institute of Industrial CatalysisSchool of Chemistry and Molecular EngineeringEast China University of Science and TechnologyShanghai200237China 

出 版 物：《Green Energy & Environment》 (绿色能源与环境（英文版）)

年 卷 期：2022年第7卷第4期

页      面：691-703页

核心收录：

学科分类：0830[工学-环境科学与工程（可授工学、理学、农学学位）] 081702[工学-化学工艺] 08[工学] 0817[工学-化学工程与技术] 0807[工学-动力工程及工程热物理] 0805[工学-材料科学与工程（可授工学、理学学位）] 080502[工学-材料学] 

基　　金：support from the National Natural Science Foundation of China(21773061,21978095) Innovation Program of Shanghai Municipal Education Commission(15ZZ031) the Fundamental Research Funds for the Central Universities。 

主　　题：Hydroxyapatite Palladium Glycerol oxidation Glyceric acid Vicinal hydroxyl group 

摘      要：Selective oxidation of glycerol provides a feasible route towards the sustainable synthesis of high value-added chemicals.Herein,the hydroxyapatite(HAP)supported palladium(Pd)species were fabricated by impregnation and subsequent calcination.The as-obtained heterogeneous Pd catalyst afforded not only excellent selectivity to glyceric acid(GLA)up to 90%with 59%conversion of glycerol but also good recyclability by using molecular oxygen as an oxidant under mild conditions.The characterization of catalysts indicated that both the surface basicity and Pd sites on the catalyst played a crucial role in promoting glycerol oxidation.Notably,it demonstrated that the presence of the vicinal hydroxyl group of glycerol molecule can assist the oxidation reaction via forming a coordination between the vicinal hydroxyl group and Ca^(2+) sites on HAP-derived catalysts.In this catalytic process,the secondary hydroxyl of glycerol kept untouched and the primary hydroxyl of glycerol was converted into carboxyl group,while the Pd species acted as active centers for cooperatively promoting the subsequent oxidation to generate GLA.Additionally,this catalytic system can be extended widely for the oxidative conversion of other vicinal diols into the corresponding a-hydroxycarboxylic acids selectively.Isotope labeling experiment using H_(2)^(18)O confirmed that H_(2)O not only acted as solvent but also was involved in the catalytic cycles.On the basis of the results,a possible reaction mechanism has been proposed.The HAP-supported Pd catalytic system has been shown to serve as an effective approach for the upgrading of bio-derived vicinal diols to high value-added chemicals.