微波加热下苯的催化氧化性能研究

研究考察了微波加热与传统电炉加热两种不同加热方式下苯的催化氧化性能,同时考察了微波加热下铜锰质量比,铈掺杂量及焙烧温度变化对铜-锰-铈/分子筛催化剂催化氧化苯性能的影响,并对催化剂进行了SEM和XRD表征.结果表明,微波加热下苯的催化氧化性能优于电炉加热,微波的"局部热点"效应、偶极极化作用与稳定的床层反应温度保证了苯的高效催化氧化;铜∶锰∶铈质量比1∶1∶0.33和焙烧温度500℃下催化剂的活性最高,苯的起燃温度与完全燃烧温度分别为165℃和230℃.催化剂表征分析可知,铜、锰氧化物及铜锰尖晶石固溶物等活性相的存在保证了催化剂的高活性;稀土元素铈的掺杂促进了活性组分在催化剂表面的分散与规整化;高温焙烧可导致催化剂表面的烧结与活性组分的团聚,从而降低其催化氧化苯的活性.

Study on Catalytic Oxidation of Benzene by Microwave Heating

The performance in catalytic oxidation of benzene was investigated in two different heating modes,microwave heating and conventional electric furnace heating.The effects of copper(Cu)-manganese(Mn) mass ratio,doping dose of cerium(Ce) and calcination temperature on the catalytic activity of Cu-Mn-Ce/molecular sieve catalyst were also checked in catalytic oxidation of benzene with microwave heating,and the catalysts were subsequently characterized by scanning electron microscope(SEM) and X-ray diffraction(XRD).The results showed that the catalyst had better catalytic activity for the oxidation of benzene under microwave heating than electric furnace heating,and high oxidation efficiency for benzene was reached due to the "local hot spots" and dipole polarization effect of microwave and stable bed reaction temperature.Under the conditions of Cu,Mn and Ce mass ratio 1∶1∶0.33 and calcination temperature 500℃,the catalyst had the optimal catalytic activity for benzene oxidation,and its light-off temperature and complete combustion temperature were 165℃ and 230℃,respectively.It was indicated by characteristics of XRD and SEM that the presence of copper and manganese oxides and Cu1.5Mn1.5O4 with spinel crystal improved the catalytic activity of the catalyst,and the doping of Ce promoted the dispersion and regularization of active components.High calcination temperature led to the sintering of the catalyst surface and agglomeration of active components,which decreased the catalytic activity of the catalyst in the catalytic oxidation of benzene.