Churipard Sathyapal R, Kanakikodi Kempanna S, Choudhuri Jyoti Roy, Maradur Sanjeev P
Materials Science and Catalysis Division, Poornaprajna Institute of Scientific, Research (PPISR) Bidalur Post, Devanahalli Bangalore-562164 Karnataka State India
Graduate Studies, Manipal Academy of Higher Education Manipal - 576104 Karnataka India.
RSC Adv. 2020 Sep 30;10(59):35988-35997. doi: 10.1039/d0ra07178a. eCollection 2020 Sep 28.
Selective oxidation of alcohols is an attractive organic transformation and has received tremendous attention from the scientific community over the years. Herein, a mesoporous polymer (MP) was synthesized by a template-free solvothermal approach. The surface of the MP was functionalized with quaternary ammonium groups and polyoxotungstate anion (PWO ) was subsequently supported on the MP as a counter anion to the ammonium cation by a simple ion-exchange procedure. The structure of PW and PW complexes was confirmed by P NMR and FTIR analysis. The surface properties of all the catalysts synthesized were explored by various characterization techniques such as nitrogen sorption, TGA, contact angle measurement, and ICP-OES analysis. The synthesized PW/MP catalysts were employed for selective oxidation of alcohols. Among the various PW supported catalysts, PW/MP (80 : 20) demonstrated excellent catalytic activity for the oxidation of alcohols using aqueous HO. The PW/MP (80 : 20) catalyst showed good catalytic activity for oxidation of a wide range of alcohols including substituted, heterocyclic and secondary alcohols. The superior catalytic activity of PW/MP (80 : 20) is attributed to an optimum balance in the hydrophilicity/hydrophobicity in the mesoporous environment, better catalyst wettability, and enrichment of reactants in the catalytic active sites.
醇的选择性氧化是一种引人注目的有机转化反应，多年来一直受到科学界的广泛关注。在此，通过无模板溶剂热法合成了一种介孔聚合物（MP）。MP的表面用季铵基团进行了功能化，随后通过简单的离子交换程序将多金属氧酸盐阴离子（PWO）作为铵阳离子的抗衡阴离子负载在MP上。通过P NMR和FTIR分析证实了PW和PW配合物的结构。通过各种表征技术，如氮吸附、热重分析（TGA）、接触角测量和电感耦合等离子体发射光谱（ICP-OES）分析，对合成的所有催化剂的表面性质进行了探究。所合成的PW/MP催化剂用于醇的选择性氧化。在各种负载PW的催化剂中，PW/MP（80∶20）对使用过氧化氢水溶液氧化醇表现出优异的催化活性。PW/MP（80∶20）催化剂对包括取代醇、杂环醇和仲醇在内的多种醇的氧化显示出良好的催化活性。PW/MP（80∶20）的优异催化活性归因于介孔环境中亲水性/疏水性的最佳平衡、更好的催化剂润湿性以及反应物在催化活性位点的富集。
