氨气改性对USY分子筛的结构及催化性能的影响  

EFFECT OF AMMONIA MODIFICATION ON STRUCTURE AND CATALYTIC PERFORMANCE OF USY

作　　者：李悦[1] 李英霞[1] 陈标华[1] 

机构地区：[1]北京化工大学化工资源有效利用国家重点实验室,北京100029

出　　处：《精细石油化工》2010年第5期17-21,共5页Speciality Petrochemicals

基　　金：国家杰出青年科学基金(20625621)

摘　　要：实验以NH_3对USY分子筛进行改性,以X射线衍射、N_2吸附-脱附、固体核磁共振和氨程序升温脱附等方法对改性前后的USY分子筛进行表征。考察了NH_3改性对USY分子筛的孔结构、酸性以及催化二异丙苯烷基转移反应性能的影响。结果表明,NH_3改性可在保持USY分子筛骨架结构的同时,有效地改善四配位骨架铝的畸变环境。改性后的USY分子筛的BET比表面积增大,介孔孔容增加。改性产生的二次介孔改善了反应物的扩散性能。催化剂性能评价表明,当反应温度为180℃,反应压力为3 MPa,质量空速为12h,n(苯):n(二异丙苯)=6:1时,经NH_3改性6 h的USY分子筛的催化性能最佳,其催化二异丙苯烷基转移反应的转化率由67.37%升至81.51%,三异丙苯含量由0.026 4%降至0.016 5%。USY zeolite was modified by NH3. The USY samples before and after NH3 modification were characterized by X-ray diffraction, N2 adsorption-desorption, solid state NMR, and NH3 temperature-programmed desorption. The effects of NHa modification on the structure, acidity, and catalytic performance of USY zeolite in the transalkylation of diisopropylbenzene were investigated. The re- sults showed that NHa modification could maintain the USY zeolite framework structure, and at the same time, effectively improve the distortion environment of four-coordinated framework aluminum, which resulted in promoting the crystallinity of the USY zeolite. With the extension of NH3 modification time, mesopore volume and specific surface areas of USY zeolite increased. Furthermore, the additional mesopores generated by NH3 modification process improved the diffusion of the reactants and products. The USY zeolite modified by NH3 for 6 h had the maximum acidity and the best catalytic performance, which increased the conversion of diisopropylbenzene by nearly 10%, and significantly improved the selectivity of the reaction, decreasing the content of triisopropylbenzene from 0. 026 4 to 0. 016 5%.

关 键 词：USY分子筛 氨气改性 畸变环境 烷基转移 

分 类 号：TQ314.24[化学工程—高聚物工业]