两步晶化法合成SAPO-34分子筛及其催化氯甲烷制低碳烯烃研究  

Synthesis of SAPO-34 with small crystallite by stepwise crystallization method and its catalytic performance in chloromethane to light olefin reaction

作　　者：孔令涛[1] 沈本贤[1] 蒋章[1] 

机构地区：[1]华东理工大学化学工程联合国家重点实验室,上海200237

出　　处：《现代化工》2015年第7期73-77,共5页Modern Chemical Industry

摘　　要：以吗啡啉为模板剂,考察了晶化条件对SAPO-34分子筛粒径的影响,利用XRD、SEM、BET和NH3-TPD等方法对所合成的SAPO-34分子筛结构性质进行了一系列表征。结果表明,当晶化温度为200℃时,降低晶化时间可以将SAPO-34分子筛的粒径从10μm左右减小到约3μm;随SAPO-34分子筛粒径减小,其硅元素质量分数略有增加,比表面积及孔体积均有所增大;NH3-TPD结果表明,减少粒径使分子筛弱酸及强酸中心的数目增加。在420℃,空速为1.89 h-1的条件下,考察了SAPO-34的粒径对其催化氯甲烷的反应影响,结果表明,减小粒径可以延缓SAPO-34分子筛失活,同时增加积碳含量,然而并未对低碳烯烃的选择性产生明显影响。Morpholine is employed as an inexpensive template for the synthesis of SAPO-34 with small crystallite by stepwise crystallization method. The physicochemical properties of SAPO-34 samples have been characterized by XRD, SEM, BET, NH3-TPD and TG. The results show that the reduction in crystallization time can decrease the particle size of SAPO-34 from 10 μm to about 3 μm at 200℃. By decreasing the size of SAPO-34 crystallite,the increase in Si content, specific surface area and pore volume of SAPO-34 sample have been observed. At the same time, NH3-TPD analysis indicates that the weak and strong acid sites are slightly increased with decreasing the size of SAPO-34 crystallite The effect of crystalline size of SAPO-34 on the catalytic performance in chloromethane conversion is investigated under 420℃ （ 1.89 h-1 ）. The results demonstrate that decreasing the size of SAPO-34 crystallite leads to the enhanced catalytic activity of SAPO-34 and the increased carbon amount, while the selectivities of light olefins are not clearly changed.

关 键 词：两步晶化法 SAPO-34 粒径 氯甲烷 低碳烯烃 

分 类 号：TQ426.94[化学工程]