酸碱处理对Hβ分子筛催化甲苯与三甲苯烷基转移性能的影响
徐朵 , 宋月芹 , 李桂军 , 史玉竹 , 张颜馨 , 周晓龙
现代化工 ›› 2026, Vol. 46 ›› Issue (9) : 176 -181.
酸碱处理对Hβ分子筛催化甲苯与三甲苯烷基转移性能的影响
Effect of alkali-acid treatment on catalytic performance of Hβ zeolite in transalkylation of toluene with trimethylbenzene
采用柠檬酸、尿素及其顺序联合处理对Hβ分子筛进行改性,以调控其孔结构与酸性分布。通过X射线衍射(XRD)、N2物理吸附-脱附、氨气程序升温脱附(NH3-TPD)和红外吡啶吸附(Py-IR)等手段对样品结构与酸性进行表征,并考察了改性前后Hβ分子筛在甲苯与偏三甲苯烷基转移反应中的催化性能。研究结果表明,不同改性处理增加了β分子筛的介孔体积,并调变了酸性分布,有效地改善了反应物和产物的扩散性能,使烷基转移反应的转化率和二甲苯收率均有不同程度的提高。其中,二者顺序联合处理分子筛的提高幅度最大,转化率从43.9%提高到50.2%,二甲苯收率从26.7%提高到34%。
Hβ zeolites were modified by citric acid,urea,and their sequential combined treatments to regulate their pore structure and acidity distribution.The structural and acidic properties of the samples were characterized by X-ray diffraction (XRD),N2 adsorption-desorption,ammonia temperature-programmed desorption (NH3-TPD),and pyridine adsorption infrared spectroscopy (Py-IR).The catalytic performance of the zeolites before and after modification was evaluated in the transalkylation reaction of toluene with 1,2,4-trimethylbenzene (1,2,4-TMB).The results demonstrate that different modification treatments increased the mesopore volume of β zeolite and modulated the acidic distribution,which effectively enhanced the diffusion properties of reactants and products.These changes led to varying degrees of improvement in both the conversion of the transalkylation reaction and the xylene yield.Among these approaches,the sequential combined treatment exhibited the most significant enhancement,increasing the conversion from 43.9% to 50.2% and the xylene yield from 26.7% to 34%.
Hβ分子筛 / 烷基转移 / 柠檬酸处理 / 尿素处理 / 二甲苯
Hβ zeolite / transalkylation / citric acid treatment / urea treatment / xylene
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