PdCl_2/Cu-HMS催化乙醇氧化羰基化合成碳酸二乙酯

制备了含Cu的介孔杂原子分子筛Cu-HM S和PdC l2/Cu-HM S催化剂,考察了其催化乙醇氧化羰基化合成碳酸二乙酯(DEC)的反应性能。通过X射线衍射、X射线光电子能谱、电感耦合等离子体原子发射光谱、红外光谱的表征表明,Cu离子以高度分散的状态进入HM S分子筛骨架,并保持了良好的介孔结构的有序性,同时PdC l2的负载在一定程度上提高了Cu-HM S分子筛的介孔规整度。通过催化剂活性的考察发现,载体表面的Pd与骨架中Cu之间的协同作用有利于该反应体系活性中心的形成,PdC l2/Cu-HM S催化剂表现出较佳的活性,DEC选择性达100.0%、乙醇转化率为5.1%、DEC时空收率达到110.50g/(L.h)。助剂的加入在不同程度上提高了PdC l2/Cu-HM S催化剂的活性,其中四乙基溴化胺(TEAB)的效果最佳,TEAB的最佳负载量为n(TEAB)∶n(Pd)=12∶1,产物DEC的时空收率达到187.93g/(L.h)。

Synthesis of Diethyl Carbonate by Oxidative Carbonylation of Ethanol over PdCl2/Cu-HMS Catalyst

Synthesis of diethyl carbonate(DEC)by gas phase oxidative carbonylation of ethanol over PdCl_2/Cu-HMS catalyst was investigated.The modified support Cu-HMS,synthesized through neutral templating route,could keep mesoporous structure even after it was calcined repeatedly to remove template.HMS,Cu-HMS and PdCl_2/Cu-HMS were characterized by means of XRD,XPS,ICP and IR.Results indicated that copper fully and highly dispersed into HMS framework.Degree of order of molecular sieves was improved after PdCl_2 was loaded on Cu-HMS.Interaction between Pd~(2+) loaded on Cu-HMS surface and Cu~(2+) in Cu-HMS framework showed synergistic effect and facilitated the producing of active centers in PdCl_2/Cu-HMS catalyst.The catalyst exhibited excellent selectivity((100.0%))to DEC,ethanol conversion(5.1%)and space time yield(STY)of DEC(110.50(g/(L·h)).)Performance of PdCl_2/Cu-HMS catalyst was greatly enhanced by addition of tetraethyl ammonium bromide(TEAB)as promoter.Under n(TEAB) ∶n(Pd)12 ∶1,STY of DEC was 187.93g/(L·h).