【摘要】 采用水热晶化法合成了不同硅铝比和晶体粒径的ZSM-5分子筛，采用X射线衍射（XRD）、X射线荧光光谱（XRF）、扫描电子显微镜（SEM）、氨气程序升温脱附（NH₃-TPD）、氮气物理吸附等进行物化性质表征，在固定床微反装置上进行二甲苯异构化反应性能评价。结果表明，纳米ZSM-5分子筛呈聚集体形貌，晶体粒径为50～100 nm,聚集体尺寸随着硅铝比增加由约500 nm增大至约1μm。ZSM-5分子筛的硅铝比由32增加至127,其酸量由0.55 mmol/g逐渐降低至0.19 mmol/g,乙苯脱烷基及二甲苯分子间、乙苯与二甲苯的烷基转移反应活性均显著降低，二甲苯收率呈升高趋势；酸量为0.24～0.55 mmol/g时，二甲苯异构化活性稳定在24.08%～24.17%。减小ZSM-5分子筛晶体粒径有利于显著增加外表面积，从而获得更高的二甲苯异构化活性，但也会使降低二甲苯收率；不同晶体粒径的ZSM-5分子筛乙苯脱烷基反应性能变化不大。更多还原

【Abstract】 ZSM-5 zeolites with different n（SiO₂）/n（Al₂O₃） ratios and crystal sizes were hydrothermally synthesized. The physical and chemical properties of the samples were investigated by X-ray diffraction（XRD）, X-ray fluorescence spectrometer（XRF）, scanning electron microscope（SEM）, NH₃-temperature programmed desorption（NH₃-TPD） and N₂ physical adsorption. The xylene isomerization performance of the samples was evaluated on a fixed bed reactor. The results indicate that the nanoscale ZSM-5 zeolite exhibits an aggregated morphology, with individual nanocrystal sizes ranging from approximately 70 nm to 100 nm. When the n（SiO₂）/n（Al₂O₃） ratio increases from 32 to 127, the size of the aggregates increases from about 500 nm to about 1 μm, while the amount of the acid sites decrease from 0.55 to 0.19 mmol/g, resulting in a significantly decrease in the activity of ethylbenzene dealkylation and trans-alkylation reactions between the xylene isomers, as well as between the xylene isomers and ethylbenzene, but an increase in the yield of xylenes. The xylene isomerization activity maintained between 24.08%-24.17% when the amount of the acid sites ranged from 0.24-0.55 mmol/g. Reducing the crystal size of ZSM-5 molecular sieve is beneficial for significantly increasing the surface area, thereby obtaining higher isomerization activity of xylene, but it also reduces the yield of xylene. On the contrary, the use of ZSM-5 zeolites with different crystal sizes results in almost no change in ethylbenzene dealkylation activity.更多还原