添加剂有机胺对丙烯选择性氧化制丙烯醛催化剂活性的影响

摘要

The catalysts for selective oxidation of propene to acrolein were prepared by coprecipitation method.The effects of organic amine addition on the performance of the catalysts for propene selective oxidation to acrolein were investigated.The results showed that with the addition of organic amine,the activity of the catalyst was stable whereas the selectivity was enhanced greatly.The catalysts were characterized by means of scanning electron microscope,X-ray diffraction,pyridine adsorbed infrared spectrum and N2-physisorption techniques.The results showed that though the surface area of the catalyst decreased slightly,the amount of L-acid sites on the catalyst surface increased obviously,which had little influence on the catalyst activity.On the other hand,the decrease of MoO3 crystallinity and the increase of (Co0.7 Fe0.3)(MoO4) crystallinity were positive factors to the selectivity of the catalyst.Meanwhile,the decreased pore volume and the increased ratio of large pores of the catalyst were attributed to the faster removal of the products from the catalyst surface and the inhibition of the formation of deep oxides.%采用共沉淀法制备丙烯选择性氧化制丙烯醛催化剂,考察有机胺的加入对丙烯选择性氧化制丙烯醛催化性能的影响.结果表明,添加有机胺后,催化剂活性在维持不变的情况下,选择性显著提高.采用扫描电镜、X射线衍射、吡啶吸附红外光谱和N2物理吸附表征等对不同催化剂的物化性能进行表征.结果发现,添加有机胺后,催化剂比表面积略有下降,但催化剂表面的L酸性中心强度明显增加,对催化剂活性影响不大；另一方面,MoO3结晶度的下降与(Co0.7 Fe0.3)(MoO4)结晶度的上升对催化剂选择性均是积极因素.同时孔容的减小以及大孔比例增加更有利于主反应产物的脱附,能抑制深度氧化物的生成.