【摘要】 对β-分子筛(n(Si)∶n(Al)=15∶1)分别进行酸洗、碱洗改性,制备出孔结构、酸性等性质不同的分子筛催化剂。通过扫描电子显微镜(SEM)、X射线衍射(XRD)、N2吸附-脱附、NH3-TPD和Py-FTIR等表征手段对分子筛催化剂的结构、性能及其在苯的烷基化反应中的应用进行了研究。结果表明,盐酸浸洗对β-分子筛的孔径、比表面积及孔容均有扩大作用,但在酸性上有所减弱; Na OH溶液浸洗造成了分子筛骨架的崩塌,对其酸性与孔结构均造成了破坏;尿素改性不仅改善了分子筛的孔结构性质,而且对分子筛酸性影响较小,是一种温和、有效的改性方式。尿素改性β-分子筛催化剂催化苯与煤基冷阱油的烷基化反应活性最好,烯烃转化率达91. 2%,且重烷基苯2位异构体(2-HAB)和3位异构体(3-HAB)在产物中含量最高,选择性分别为50. 1%和33. 5%,占整个烷基化产物的84%。更多还原

【Abstract】 Molecular sieve catalysts with different pore structures and acidity were prepared by acid pickling and alkali washing modification of β-molecular sieve with n( Si) ∶ n( Al) = 15 ∶ 1. The structure,properties,and the application of β-molecular sieve catalysts in alkylation of benzene were investigated by scanning electron microscopy( SEM),X-ray diffraction( XRD),N2 adsorption-desorption,NH3-TPD( temperature programmed desorption) and Py-FTIR( Fourier transform infrared spectroscopy). The results show that hydrochloric acid leaching can enlarge the pore size,specific surface area and pore volume of β-molecular sieve,but weaken the acidity,while the sodium hydroxide solution leaching results in the collapse of molecular sieve skeleton,leading to the destruction of the acidity and the pore structure. Modification by urea not only improves the pore structure of molecular sieve,but also has little effect on the acidity of molecular sieve. It is a mild and effective way to modify the molecular sieve. β-molecular sieve catalyst modified with urea has the best activity in alkylation of benzene with coal-based cold trap oil: the conversion of olefin is91. 2%,and the selectivities of 2-HAB( heavy alkylbenzene) and 3-HAB isomers are 50. 1% and 33. 55%,respectively,accounting for 84% of the total alkylation product.更多还原