利用红外光谱分析乙酸锌催化合成2,4-甲苯二氨基甲酸甲酯的反应机理

利用红外光谱技术研究了无水乙酸锌催化2,4-二氨基甲苯与碳酸二甲酯反应生成2,4-甲苯二氨基甲酸甲酯的甲氧基羰基化反应机理.结果表明,碳酸二甲酯羰基碳上的氧与无水乙酸锌中的Zn2+配位形成配合物,无水乙酸锌的结构由双齿型转变为单齿型,同时使DMC的羰基碳被活化.然后2,4-二氨基甲苯作为亲核试剂,其氨基进攻配合物中碳酸二甲酯上被活化的羰基碳原子,发生甲氧基羰基化反应,配合物中的Zn-O配位键断裂,生成2,4-甲苯二氨基甲酸甲酯和甲醇,并使无水乙酸锌的结构重新回到双齿型.     

甲酸钠增敏鲁米诺化学发光机理研究及应用

在表面活性剂十二烷基苯磺酸钠(SDBS)存在下,传统意义上的自由基清除剂甲酸钠反而对铬酸钾一鲁米诺-腺嘌呤化学发光体系表现出了很好的化学发光增敏效果,文章通过化学发光发射光谱,紫外可见光谱及化学反应等手段探讨了这一化学发光体系的增敏机理,结果表明:化学发光体系的增敏是由于反应体系中甲酸钠的存在使原有发光体系中的羟基自由基(OH·)转化为氧自由基(O2·)所致.以此为基础建立了流动注射化学发光法测定腺嘌呤的高灵敏方法,腺嘌呤在2.45×10-11～8.18×10-9 mol·L-1范围内成良好的线性关系(R2=0.999 3),检出限为8.72×10-12 mol·L-1.该法已成功用于测定维生素B4药品中的腺嘌呤的含量,结果令人满意.     

彩色负片印片颗粒指数的准确测定

分析了彩色负片印片颗粒指数σper实际测试中不同性能负片的测试特点和影响因素。印片颗粒指数的测试点应根据彩色负片的感光特性确定,为正常扩印时对应正片0．74中灰密度的负片密度点。影响印片颗粒指数值的两个主要因素是彩色相纸的反差修正系数α和彩色负片的覆盖力系数ECP;建立了α和ECP的实验求取方法,并通过对几种负片参量的实际测定,分析和说明了参量变化对印片颗粒指数数值的影响程度和应进行的修正。     

冠状圆板式橡胶支座力学性能测试

 使用应变片式压力传感器, 对冠状圆板式橡胶支座力学性能进行 测试, 得出不同工况下橡胶支座底部压力分布规律.     

Preparation of imprinted monolithic column under molecular crowding conditions

Molecular crowding is a new concept to obtain molecularly imprinted polymers(MIPs) with greater capacity and selectivity.In this work,molecular crowding agent was firstly applied to the preparation of MIPs monolithic column.A new polymerization system based on molecular crowding surrounding was developed to prepare enrofloxacin-imprinted monolith,which was composed of polystyrene and tetrahydrofuran.The result showed that the monolithic MIPs under molecular crowding conditions presented good molecular recognition for enrofloxacin with an imprinting factor of 3.03.     

Meso-macroporous Al2O3 supported Ru catalysts for CO preferential oxidation in hydrogen-rich gases

Series of meso-macroporous Al2O3 supported Ru catalysts with different loadings were prepared by incipient wetness method and applied to preferential oxidation of CO in hydrogen-rich gases. N2 adsorption-desorption, SEM, XRD, TEM, CO chemisorption and H2 -TPR techniques were employed to characterize the catalysts. The results indicate that Ru/Al2O3 catalysts have meso-macroporous structure, high surface area and high metal dispersion. The characterization results of XRD and CO chemisorption indicate the entry of Ru ions into Al2O3 lattice. The results of catalytic performance tests indicate that the meso-macroporous Al2O3 supported Ru catalysts for CO preferential oxidation showed good activity under high space velocity. It is proposed that the macropores in the Ru/Al2O3 catalyst favor mass transfer and mesopores help to improve the dispersion of metal, resulting in the excellent catalytic performance.     

一维CdS/TiO2纳米材料的制备及其光催化性能

采用含有氯化镉和硫脲的钛溶胶对钛酸纳米管载体进行修饰,再经焙烧制得不同CdS含量的一维CdS/TiO2纳米材料.运用X射线衍射、透射电子显微镜、N2吸附-脱附、紫外-可见光谱和X射线光电子能谱等手段表征了材料的结构和性质,并考察了CdS/TiO2样品在紫外光及模拟日光条件下光催化降解甲基橙溶液的活性.结果表明,经高温焙...     

The synthesis of porphyrin-anthraquinone dyad via an azo-rearrangement

One novel porphyrin P-Q2 is planned to be synthesized by condensation between ATPP and Q1.However,after separation by chromatography and characterization with IR,~1H NMR,HR-MS and X-ray,P-Q1 is obtained unexpectedly.Compared the structure of P-Q1 with that of P-Q2,it is realized that an intramolecular cyclization rearrangement takes place when the azo group is situated in the O-position to the amido group.This rearrangement offers a new way to prepare indazole heterocycle.In addition,the spectral properties of P-Q1 have been studied by UV-vis and steady state fluorescence spectroscopy.Strong fluorescence quenching is observed in the preliminary emission spectrum due to the proposed electron transfer from the excited porphyrin to the anthraquinone moieties.     

Synthesis of porous hematite nanorods loaded with CuO nanocrystals as catalysts for CO oxidation

Porous hematite (α-Fe2O3) nanorods with the diameter of 20-40 nm and the length of 80-300 nm were synthesized by a simple surfactant-assisted method in the presence of cetyltrimethylammonium bromide (CTAB).The α-Fe2O3 nanorods possess a mesostructure with a pore size distribution in the range of 5-12 nm and high surface area,exhibiting high catalytic activity for CO oxidation.CuO nanocrystals were loaded on the surface of porous α-Fe2O3 nanorods by a deposition-precipitation method,and the catalysts exhibited superior activity for catalytic oxidation of CO,as compared with commercial α-Fe2O3 powders supported CuO catalyst.The enhanced catalytic activity was attributed to the strong interaction between the CuO nanocrystals and the support of porous α-Fe2O3 nanorods.     

磺化苯膦酸锆的制备及其催化酯化反应研究

以苯和三氯化磷等小分子化合物为原料,合成制备了固体酸催化剂磺化苯膦酸锆,用红外光谱、Ｘ－射线衍射方法对其结构表征,并研究其在酯化应中的催化活性。实验结果表明：磺化苯膦酸锆是一种具有层状结构的活性较高的固体酸催化剂,乙酸丁酯,氯乙酸丁酯反应温度控制在１１０～１２０℃,产物收率在８０％以上,催化剂重复使用多次后用稀酸浸泡可恢复活性。