摘要
在正己胺体系下,采用晶种辅助法合成了系列高硅ZSM-5分子筛,通过XRD、ICP、SEM、NH3-TPD和N2吸附-脱附等方法对分子筛进行了表征,考察了不同形貌的ZSM-5分子筛与传统丝光沸石的甲苯歧化反应性能。与丝光沸石相比,ZSM-5分子筛在抑制C9+重芳烃副产物的生成上具有明显优势,是潜在的高二甲苯收率的甲苯歧化催化剂。此外,ZSM-5分子筛的形貌对甲苯歧化反应性能及产物分布有明显的影响。长片状ZSM-5分子筛(2μm×100 nm×20 nm)具有典型的短b轴结构,能有效提高(010)孔道方向的扩散性能,抑制二甲苯深度反应生成C9+重芳烃。相同反应条件下,与硅铝比相近的块状ZSM-5分子筛相比,长片状ZSM-5分子筛的初始甲苯转化率由46.6%提高到50.0%,产物中二甲苯含量由21.4%(w)提高到23.0%(w),且稳定性较好。
A series of high silicon ZSM-5 zeolite with different morphologies were synthesized by using the seed-assisted method with n-hexylamine as a template,and characterized by XRD,ICP,SEM,NH3-TPD and N2 adsorption-desorption methods.Catalytic performances for toluene disproportionation over ZSM-5 and traditional mordenite zeolites were investigated.Compared with MOR,ZSM-5 shows obvious advantage over inhibiting the formation of C9+aromatics by-product and is a potential catalyst for toluene disproportionation with a high yield of xylene.Furthermore,the morphology of ZSM-5 exhibits great influence on the catalytic activity and product distribution for the toluene disproportionation reaction.The long-flake ZSM-5(2μm×100 nm×20 nm)with a typical short b-axis structure can efficiently improve the diffusion performance of(010)channel direction and inhibit the deep reaction of xylene to generate C^+9 aromatics.Under the same reaction conditions,compared with the bulk ZSM-5 under the similar silicon-alumina ratio,the toluene conversion of the long-flake ZSM-5 increases from 46.6%to 50.0%,while the xylene content in the product increases from 21.4%(w)to 23.0%(w),with an obviously improved catalytic stability.
作者
李华英
丁键
石张平
李经球
孔德金
Li Huaying;Ding Jian;Shi Zhangping;Li Jingqiu;Kong Dejin(State Key Laboratory of Green Chemical Engineering and Industrial Catalysis,Sinopec Shanghai Research Institute of Petrochemical Technology,Shanghai 201208,China;School of Chemistry and Molecular Engineering,East China Normal University,Shanghai 200241,China)
出处
《石油化工》
CAS
CSCD
北大核心
2020年第6期529-537,共9页
Petrochemical Technology
关键词
ZSM-5分子筛
正己胺
孔道
甲苯歧化
ZSM-5 zeolite
n-hexylamine
pore structure
toluene disproportionation
