纳米ZSM-5分子筛的酸脱铝改性及其催化萘和甲醇的烷基化反应性能  

Dealumination of ZSM-5 Nanocrystals With Different Acids and Their Catalytic Performances in Methylation of Naphthalene With Methanol

作　　者：王文静[1] 武光[1] 吴伟[1] 王高亮[1] 昝望[1] 戚鑫[1] 

机构地区：[1]黑龙江大学催化技术国际联合研究中心、高效转化的化工过程与技术黑龙江普通高校重点实验室、化学化工与材料学院,黑龙江哈尔滨150080

出　　处：《石油学报（石油加工）》2014年第4期620-628,共9页Acta Petrolei Sinica(Petroleum Processing Section)

基　　金：国家自然科学基金项目(21276067)资助

摘　　要：分别采用盐酸、草酸、柠檬酸对晶种引导的无模板剂合成的纳米ZSM-5分子筛进行脱铝改性,利用XRD、N2吸附-脱附、27 Al NMR、XRF、NH3-TPD、Py-IR等方法对其进行表征,并考察了不同种类的酸脱铝对ZSM-5分子筛的结构、酸性及其催化萘与甲醇的烷基化反应性能的影响。结果表明,盐酸、柠檬酸与草酸均可脱除分子筛的骨架铝和非骨架铝,但3种酸对分子筛的脱铝程度不同。纳米ZSM-5分子筛经酸脱铝后,在脱除了部分强酸中心的同时产生了一定比例的二次介孔,有效地改善了反应物和产物的扩散性能,使催化萘与甲醇的烷基化反应的萘转化率、2,6-二甲基萘(2,6-DMN)选择性和产物中n(2,6-DMN)/n(2,7-DMN)均有不同程度的提高,并且表现出更强的抗失活能力。The dealumination of ZSM-5 nanocrystals synthesized by the preset crystal seed-induced method without any organic template was carried out with aqueous solutions of hydrochloric acid, oxalic acid and critic acid, respectively. The ZSM-5 nanocrystal samples before and after dealumination were characterized by XRD, N2 adsorption-desorption,27 A1 MAS NMR, XRF, NH3- TPD, Py-IR. The effects of dealumination on the structure, acidity and catalytic performance of ZSM-5 nanocrystals in the alkylation of naphthalene were investigated. The results showed that the framework A1 and extra-framework A1 could be synchronously removed by hydrochloric acid, oxalic acid and critic acid, respectively, but with different extent of dealumination. Part of the strong acid centers in ZSM-5 nanocrystals was removed and several secondary mesopores were formed, which effectively improved the diffusion performance of the reactants and products. The alkylation of naphthalene catalyzed by dealuminated ZSM-5 nanocrystals got higher conversion of naphthalene, higher selectivity of 2,6-DMN, higher n （2, 6-DMN）/n （2, 7-DMN） and stronger resistance to inactivation, compared to that catalyzed by parent sample.

关 键 词：纳米分子筛 ZSM-5 酸脱铝 烷基化 2 6-二甲基萘 

分 类 号：TQ426.94[化学工程]