作　　者： ; ; ; ; ; ;

机构地区： 中国石油大学北京化学化工学院CNPC催化重点实验室

出　　处： 《物理化学学报》 2009年第3期539-544,共6页

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%. 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 cm^3·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^3·g^-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.

关 键 词： 沸石 多级孔结构 混合 烃 催化裂解 氟矿化体系

领　　域： [理学] [理学]