Characterization of H-FER and H-TON using temperature-programmed desorption of alkylamines

Simultaneous temperature-programmed desorption (TPD) and thermogravimetric analysis (TGA) measurements were performed with n-propylamine and isopropylamine in H-FER and H-TON in order to test whether the Brønsted-acid sites associated with the 10-ring, straight channels in H-FER could be distinguished from the acid sites in the side cavities. In H-TON, the saturation uptakes were identical for both amines, as were the acid-site densities determined from the amounts of amine which reacted to olefin and ammonia products above 600 K. By contrast, the saturation uptake for isopropylamine in H-FER was much lower than the uptake of n-propylamine and the site density determined from the amounts which react were also significantly lower. It is argued that the n-propylamine results for H-FER provide a measure of the total Brønsted-acid-site density, while the isopropylamine results provide a measure of the site density in the 10-ring channels.     

Catalytic Activities of Alcohol Transformations Over 8-Ring Zeolites

Aluminosilicate H/CHA and H/MTF zeolites show remarkably different catalytic activities in the methanol and ethanol transformations although they have similar pore size of 8-membered ring structures. Moreover, the produced ethylene is further converted on H/CHA, but H/MTF is not active for the ethylene transformation. The correlations between the distinct catalytic differences and their intrinsic structural properties, including topology and acidity, are discussed.     

CH3ONO 与 Br 自由基反应的机理研究

运用量子化学B3LYP方法,在6－311＋＋g（ d,p）基组水平上研究Br自由基和CH3 ONO的反应机理,优化得到了反应途径上反应物、过渡态和产物的几何构型;在B3LYP／6－311＋＋g（ d,p）优化的构型基础上,以CPCM模型得到了其在水溶液中各点的能量。研究结果表明：Br自由基与CH3 ONO有3种反应机制。第1种是Br自由基加成到CH3 ONO分子C原子上消除NO2的机制,第2种是Br自由基加成到CH3 ONO分子甲氧基O原子上消除NO的加成－消除机制,第3种是Br自由基对H直接夺取的机制。     

天然抗氧化剂的筛选

对７００余种中药和香辛料的抗氧化活性进行了大规模的筛选，发现有６４种植物有明显的抗氧化活性，２４种植物的抗氧化活性很强。其中有几种植物的抗氧化活性的筛选和研究，如荔枝草，降真香，紫草，血竭是以前未见报道过的。     

Effect of calcination temperature on the characteristics of SO<Emphasis Type="Italic">sk</Emphasis>4/2-/TiO<Subscript>2</Subscript> catalysts for the reduction of NO by NH<Subscript>3</Subscript>

The catalytic activity of sulfated titania (ST) calcined at a variety of temperatures has been investigated for selective catalytic reduction (SCR) of NO by NH₃. The NO removal activity of ST catalyst mainly depends on its sulfur content, indicating critical role of sulfur species on the surface of TiO₂. The role of sulfur is mainly the formation of acid sites on the catalyst surface. The presence of both BrØnsted and Lewis acid sites on the surface of sulfated titania has been identified by IR study with the adsorption of NH₃ and pyridine on ST. The reduction of the intensity of IR bands representing BrØsted acid sites is more pronounced than that revealing Lewis acid sites as the calcination temperature increases. It has been further clarified by IR study of ST500 catalyst evacuated at a variety of temperatures. The NO removal activity also decreases with the increase of the catalyst calcination temperature. It simply reveals that BrØnsted acid sites induced by sulfate on the catalyst surface are primarily responsible for the enhancement of catalytic activity of ST catalyst containing sulfur for NO reduction by NH₃.     

离子液体中间体1-丁基-3-甲基咪唑溴盐的合成

以N-甲基咪唑和1-溴代正定烷为原料合成1-丁基-3-甲基咪唑溴盐[Bmim]Br,研究了反应时间、反应温度、及N-甲基咪唑与1-溴代正丁烷的摩尔比(原料比)和溶剂对[Bmim]Br收率的影响,产物结构经过1H NMR及FT-IR确认.实验结果表明,反应温度在60℃,反应时间为24h,N-甲基咪唑与1-溴代正丁烷的摩尔比(原料比)为1:1.2时,收率为93.13%.     

Negative thermal quenching CsPbBr3 glass-ceramic based on intrinsic radiation and vacancy defect co-induced dual-emission

Halide perovskite glass-ceramic has recently moved into the center of the attention of perovskite research due to their potential for temperature sensing. However, quantum dots glass-ceramic with excellent luminescence performance still needs to be combined with rare-earth (RE) ions to accurately measure temperature. In this work, a novel non-RE doped dual-emission (460 nm and 512 nm) CsPbBr₃ quantum dots was obtained in telluride glass via the friction crystallization method, where 512 nm was derived from intrinsic luminescence of quantum dots, and 460 nm was originated from thermally induced bromine vacancy, which can be used for temperature sensing. Fluorescence intensity ratio results indicate that the relative sensitivity of dual-emission could reach 5.6 % K^?1 at 323 K. The discovery of non-RE doped CsPbBr₃ QDs glass-ceramic with negative thermal quenching uncovers a new optional sensing glass material that surpass traditional RE-doped QDs glass by their tunability and sensitivity.     

BrФnsted-Lewis双酸性离子液体催化大豆油制备生物柴油

设计合成了一系列BrФnsted–Lewis双酸性离子液体[Py(CH2)4SO3H][HSO4]/MCl X,将其用于催化酯交换制备生物柴油。考察了金属氯化物的种类及其与[Py(CH2)4SO3H][HSO4]的摩尔比对离子液体催化性能的影响。结果显示:离子液体[Py(CH2)4SO3H][HSO4]–2Fe Cl3具有最好的催化性能。在其作为催化剂时,考察了醇油摩尔比、催化剂用量、反应温度和反应时间对生物柴油收率的影响。结果表明:当醇油摩尔比为8∶1,催化剂用量为5%(相对于原料油质量),反应温度为130℃,反应时间为6 h时,生物柴油收率可达96.2%。离子液体具有较好的重复使用能力,重复使用6次后,生物柴油收率没有明显降低。     

采用能量色散X荧光仪同时测定Co,Mn,Br元素

建立了用能量色散X荧光仪同时测定Co,Mn,Br 3种共存元素的新方法。优化了操作条件,讨论了影响因素,考察了方法的精密度和准确度。其中Co回收率为95.3％-103.0％,Mn回收率为96.0％-104.0%,Br回收率为94.8％-105.0％。用于精对苯二甲酸化工装置试样中Co,Mn,Br的同时测定,结果满意。