On the effect of mesoporosity of FAU Y zeolites in the liquid-phase catalysis
On the effect of mesoporosity of FAU Y zeolites in the liquid-phase catalysis
复制标题
DOI：
10.1016/j.micromeso.2018.12.003
复制
发表时间：
2019-04
影响因子：
5.2
通讯作者：
Rongxin Zhang;Shaojun Xu;D. Raja;Nor Binti Khusni;Jinmin Liu;Jiaoyu Zhang;Samer Abdulridha;Huan Xiang;Songshan Jiang;Yanan Guan;Yilai Jiao;Xiaolei Fan
中科院分区：
文献类型：
--
作者：
Rongxin Zhang;Shaojun Xu;D. Raja;Nor Binti Khusni;Jinmin Liu;Jiaoyu Zhang;Samer Abdulridha;Huan Xiang;Songshan Jiang;Yanan Guan;Yilai Jiao;Xiaolei Fan
采用N2物理吸附、汞孔率测定、氨程序升温脱附（NH_3-TPD）和吡啶傅里叶变换红外（吡啶-IR）分析等方法，对HY-2.6和脱铝HY-15/-30三种工业用FAU Y分子筛的孔率和酸性进行了综合研究。N2物理吸附和Hg孔隙率测定是评价脱铝样品中分级介孔性的有用工具，揭示HY-15和HY-30在5-10 nm的介孔范围内具有>50%的开放介孔性。脱铝后Y型分子筛的酸性比HY-2.6分子筛的酸性明显降低，如HY-2.6分子筛经脱铝后，其布氏酸性降低了69倍。甲醇与羧酸的Fischer酯化反应和苯甲醛与正庚醛的羟醛缩合反应的催化结果表明，脱铝Y型分子筛的介孔性在液相反应中起着关键作用。例如，在月桂酸与甲醇的酯化反应中，具有分级介孔的HY-15和HY-30表现出比HY-2.6（4.0%）更好的催化活性（即月桂酸的转化率分别为7.9%和24.5%）。催化结果的分析沿着酸性性质表明，酸性的影响小于沸石催化剂的孔隙率。这一结果解释了中孔沸石在液相催化中高活性的原因。
The porosity and acidity of three commercial FAU Y zeolites (including the original HY-2.6 and dealuminated HY-15/-30 zeolites) were studied comprehensively using nitrogen (N2) physisorption, and mercury (Hg) porosimetry, ammonia temperature-programmed desorption (NH3-TPD) and pyridine Fourier transform infrared (pyridine-IR) analyses. The combined N2physisorption and Hg porosimetry is a useful tool to evaluate the hierarchical mesoporosity in the dealuminated samples, revealing that HY-15 and HY-30 possess >50% open mesoporosity in the mesopores range of 5–10 nm. The acidity of the dealuminated Y zeolites has been reduced significantly in comparison to that of the original HY-2.6,e.g.Brønsted acidity decreased byca.69 folds by dealuminating HY-2.6 to HY-30. Catalytic results of Fischer esterification of methanol with carboxylic acids and aldol condensation of benzaldehyde with 1-heptanal have evidenced that the critical role of mesoporosity of the dealuminated Y zeolites in liquid-phase reactions. For example, in the esterification of lauric acid with methanol, HY-15 and HY-30 with hierarchical mesopores showed better catalytic activity (i.e.conversion of lauric acid: 7.9% and 24.5%, respectively) than HY-2.6 (4.0%). The analysis of the catalytic results along with the acidic property suggests that the acidity is less influential than the porosity of zeolite catalysts. Results from this study allow us to explain the origin of the high activity of zeolites with mesoporosity in the liquid-phase catalysis.