硅羟基对二氧化硅固载有机锡酯交换催化性能的影响

发布时间：2018-06-03 20:57

  本文选题：有机锡 + 固载　； 参考：《化工学报》2017年05期

【摘要】：采用新方法制备了二氧化硅固载有机锡。以无机Sn Cl4为锡源,在合成有机锡的同时制备有机锡硅烷试剂,再将其固载到二氧化硅上,用于碳酸二甲酯与苯酚酯交换合成碳酸二苯酯的反应。通过不同的制备方法和处理方法,制得不同硅羟基含量的二氧化硅载体;研究硅羟基对锡固载量及固载有机锡催化性能的影响。TG与ICP表征显示,锡固载量与二氧化硅载体的硅羟基含量正相关。29Si MAS NMR表征发现,制备的固载有机锡中含有较多的T2和T3物种,利于有机锡的稳定固载。二氧化硅硅羟基含量越高,催化剂的锡固载量越高,活性越好。介孔二氧化硅为载体制备的Sn-MSiO_2表现出最好的催化活性:用量1.0 g,在150～180℃反应9 h,苯酚转化率达50.4%,酯交换选择性高于99.9%;用0.5 g考察重复使用性能,重复使用5次,苯酚转化率由41.2%降低到35.0%。锡流失是活性下降的主要原因。
[Abstract]:Silica supported organotin was prepared by a new method. Organotin silane reagents were synthesized from inorganic Sn Cl4 as tin source and immobilized on silica to synthesize diphenyl carbonate by transesterification of dimethyl carbonate with phenol. Silica carriers with different silica hydroxyl contents were prepared by different preparation and treatment methods, and the effects of silica hydroxyl groups on tin immobilization capacity and catalytic properties of organotin were investigated by TG and ICP. The results showed that there were more T _ 2 and T _ 3 species in the supported organotin, which was beneficial to the stable fixation of organotin. The higher the hydroxyl content of silica, the higher the tin immobilization capacity and the better the activity of the catalyst. The Sn-MSiO_2 prepared by mesoporous silica as carrier showed the best catalytic activity: dosage 1.0 g, reaction at 150 鈩，

本文编号：1974155