以常见的非均相Schiff碱配合物Cr(salten)-MCM-41(salten:N,N-双水杨醛缩二乙烯三胺)的制备过程为例,考察了均相配合物制备过程中金属盐的种类、配位体系的pH值及固载过程中的偶联剂用量对所制备的非均相配合物的结构和催化性能的影响.结果表明,由阴离子配位能力较弱的氯化物和硝酸盐提供金属中心,保持配位体系处于中性环境,并使用适量的偶联剂制备非均相配合物,其结构完整且在苯甲醇选择性氧化反应中催化性能较高.在最佳条件下,苯甲醇转化率最高可达49.9%,苯甲醛的选择性为100%,所制备的催化剂重复使用6次后仍具有较高的催化性能.
As far as a typical preparation process of the immobilized Schiff base complex Cr(salten)-MCM-41 is concerned,the effect of the kinds of metal salts,the pH values of coordination system and the amount of linkers on its structure and catalytic performance in selective oxidation of benzyl alcohol was investigated in detail.The results revealed when the metal centers were provided by chlorides and nitrates with weak coordination ability,the coordination systems were kept neutral,and the amount of linkers was appropriate,the obtained immobilized Schiff base complexes exhibited complete coordination structure and also showed the best catalytic performance with the selectivity to benzaldehyde of 100% at a conversion of benzyl alcohol of 49.9%.In addition,the catalytic activity is remained after being recycled 6 times.