【摘要】 以非离子表面活性剂壬基酚聚氧乙烯醚(TX-15)为模板,设计氟化铵作为矿化剂,在近中性条件下直接合成了具有微孔-介孔复合孔道的铵型β沸石.合成样品采用粉末X射线衍射(PXRD),高分辨扫描电子显微镜(SEM),微分热重(DTG)以及氨程序升温脱附(NH3-TPD)等手段进行了表征.结果表明,氟离子及非离子表面活性剂的加入对沸石的孔结构、酸性质均起到了一定的调变作用.该沸石具有发达的呈梯级分布的多级孔结构,孔容高达0.67 cm3.g-1,且具有较强的Bronsted酸和适度分布的Lewis酸,大大改善了反应物和产物分子的扩散和反应性能.在混合C4烃的催化裂解反应中,该沸石与传统方法合成的β沸石相比,其转化率提高了约15%,烯烃(乙烯和丙烯)产率提高了近10%,芳烃(苯和甲苯)产率提高了3%.更多还原

【Abstract】 NH4-β zeolite with hierarchical porous structure was directly prepared in a nearly neutral synthetic system using nonionic compound(polyoxyethylene nonyl phenylether) as the mesoporogen and fluoride as a mineralizer.Samples were characterized by powder X-ray diffractometry(PXRD),scanning electron microscopy(SEM),NH3-temprature programmed desorption(NH3-TPD),N2 adsorption/desorption and differential thermogravimetry(DTG).N2 analysis results showed that the synthesized H-(NH4)-β zeolite contained stepwise distributed micro-mesoporous structure.The Barrett-Joyner-Halenda(BJH) method of analyzing the N2 adsorption isotherm showed that the mesopore volume was 0.67 cm3.g-1 and the most probable pore size was about 21.8 nm.This value was higher than that for the conventional H-β zeolite(0.37 cm.3g-1 and 3.8 nm).The large amount of Lewis acid and the moderate amount of Bronsted acid in the H-(NH4)-β zeolite was examined by means of Pyridine-IR spectroscopy.Compared to conventional H-β zeolite,the conversion in the catalytic cracking reaction of mixed C4 hydrocarbons using this H-(NH4)-β zeolite was improved by 15%.Yields for the olefins(ethene and propene) and aromatic hydrocarbons(benzene and toluene) increased by 10% and 3%,respectively.更多还原