摘要
在400-550℃的不同焙烧温度下,制备了氟改性的纳米HZSM-5分子筛催化剂。利用XRD、N2吸附/脱附和NH3-TPD技术对氟改性前后催化剂的结构和酸性进行了表征,并在固定床反应器上考察了其催化甲醇制丙烯反应的催化性能。结果表明,氟改性可明显降低酸中心的数量及强度,从而显著提高丙烯的选择性和催化剂的稳定性。由于在450℃下焙烧的催化剂出现了新的强酸,使催化剂的稳定性和丙烯的选择性都略有下降。当焙烧温度达到550℃时,由于比表面积和孔体积大大降低,导致催化剂的稳定性显著下降。
A series of fluorinated nanoscale HZSM-5 zeolite catalysts were prepared by calcining at different temperatures in the range of 400-550 ℃.The structures and acidic properties of the samples before and after fluorination were investigated by XRD,N2 adsorption/desorption and NH3-TPD techniques.The performances of the catalysts in the reaction of methanol to propylene were evaluated in a fixed-bed micro-reactor.The results showed that the amount and intensity of the acid sites decreased after fluorination,which resulted in the significant increase of propylene selectivity and catalytic stability.It was found that new strong acid sites appeared in the sample calcined at 450 ℃.As a result,both the selectivity of propylene and stability of catalyst decreased slightly.When the calcination temperature was increased to 550 ℃,the stability of the fluorinated sample decreased distinctly due to the significant decrease of the surface area and pore diameter.
出处
《上海应用技术学院学报（自然科学版）》
2009年第4期310-313,共4页
Journal of Shanghai Institute of Technology: Natural Science
基金
上海市教委重点科研项目(06ZZ81)
上海应用技术学院引进人才科研启动项目(YJ2005-16)
关键词
纳米HZSM-5分子筛
氟改性
焙烧温度
甲醇
丙烯
nanosized HZSM-5 zeolite
fluorine modification
calcination temperature
methanol
propylene
