论文部分内容阅读
以2-吡啶甲醛与苯胺及其衍生物缩合制备了3个双氮席夫碱配体,对其结构进行了表征.研究了席夫碱配体与甲基三氧化铼(MTO)在催化反应体系中的原位配位作用对MTO催化30%H2O2环氧化烯烃反应的影响.结果表明,含吸电子基羧基的双氮席夫碱配体(I)由于具有适宜的配位能力和酸性,在较低温度下与MTO配位可显著提高烯烃环氧化反应选择性,而反应速率没有明显降低.例如,以30%H2O2为氧化剂环氧化环己烯,当I与MTO的摩尔比为2,反应温度10℃时反应4 h,环己烯的转化率达到94.6%,环氧化物选择性高达99.0%.不具羧基的双氮席夫碱配体与MTO配位,尽管可以提高环氧化物的选择性,但同时却降低了MTO的催化活性.
Three Schiff base ligands were synthesized by the condensation of 2-pyridinecarboxaldehyde with aniline and its derivatives, and their structures were characterized. The effects of Schiff base ligands and methyltin trioxide (MTO) System on the reaction of MTO catalyzed epoxidation of 30% H2O2 epoxidation olefins.The results show that the double nitrogen Schiff base ligands (I) containing electron-withdrawing carboxyl groups have the appropriate coordination ability and acidity , At lower temperature and MTO coordination can significantly improve the selectivity of olefin epoxidation reaction, and the reaction rate was not significantly reduced.For example, with 30% H2O2 as oxidant epoxidation of cyclohexene, when I and MTO molar ratio Was 2, the reaction temperature was 10 ℃ for 4 h, the conversion of cyclohexene reached 94.6% and the selectivity of epoxide was as high as 99.0% .The bis-Schiff base ligands without carboxyl group coordinated with MTO, Oxide selectivity, but at the same time it reduces the catalytic activity of MTO.