N-甲基咪唑配体络合金属Cu(I)催化剂对水中2,4-二甲氧基溴苯还原脱溴

Catalytic dehalogenation of 1-bromo-2,4-dimethoxybenzene in water by SBA-15 immobilized Cu( I)-NHC

合成了以N-甲基咪唑为配体,Cu为活性中心的络合金属多相催化剂Cu(I)-NHC-SBA-15。通过1H-NMR、13CNMR、有机元素分析和FTIR对各步合成反应产物结构经行了鉴定;用SEM、N2吸附脱附等方法对催化剂进行了表征;用ICP测定了催化剂Cu含量。对催化剂催化2,4-二甲氧基溴苯还原脱溴活性进行了测试。在反应时间为24 h,通过正交实验和单因素实验,考察了催化剂用量、反应温度、还原剂用量等因素对脱溴率的影响,并确定了最佳反应条件:催化剂用量为0.05 g、水合肼用量为2 m L、反应温度为80℃,脱溴效果较好,脱溴率达到98.5%。对催化剂重复使用进行了初步研究。对催化反应动力学进行了初步研究,结果表明,该多相催化反应是由表面反应速度控制,并符合一级动力学反应。对反应机理进行了初步探讨。

Heterogeneous metal complex catalyst Cu( I)-NHC-SBA-15 was synthesized in four-component reactions among N-methylimidazole,Cu I,( 3-chloro-propyl) triethoxysilane and SBA-15. The product of each step was detected by1H-NMR,13C-NMR,organic elemental analysis and FTIR. The catalyst was characterized by SEM and N2adsorption-desorption. The copper in the catalyst was detected by ICP. The activity of catalyst was tested.The effects of catalyst amount,reaction temperature and hydrazine hydrate amount on catalytic debromination of 1-Bromo-2,4-dimethoxybenzene in the water were studied. In 24 hours,the optimal reaction conditions were obtained via the orthogonal and single factor experiments as follows: the catalyst dosage of 0. 05 g,hydrazine hydrate dosage of 2 ml and at 80℃. The efficiency of catalytic debromination reached 98. 5%. The reuse of catalyst was studied. The catalytic reaction dynamics was also studied. The results indicated that the catalytic debromination reaction was determined by the surface reaction and followed the first order kinetics. The possible mechanism of catalytic debromination was proposed.