用DCC/DMAP合成N-苄氧羰基氨基酸薄荷酯

以乙腈为溶剂, 用DCC/DMAP偶合法合成了5个N-苄氧羰基氨基酸薄荷酯, 产率90%～94%. 起始原料氨基酸包括: 甘氨酸, DL-蛋氨酸, β-丙氨酸, L-缬氨酸和L-脯氨酸. 给出了目标产物的氢谱、碳谱、红外光谱、质谱、高分辨质谱和元素分析数据.     

纳米晶PbTiO3负载CuO催化NO分解

A large specific surface area perovskite-type mixed oxide PbTiO₃ supported cupric oxide was synthesized as a catalyst for NO decomposition and characterized by techniques such as XPS, XRD, H₂-TPR before and after NO decomposition reactions. The catalytic properties were tested with a fix-bed micro-reactor. The results showed that the PbTiO₃ was inactive for the reactions, but 1wt % Cu/PbTiO₃ catalyst gave fairly good activities for NO decomposition at temperature as low as 473 K. Copper species were found well-dispersed but weakly interacted with the support before NO decomposition, and the NO decomposition caused significant change in the environment of the copper species, which became Cu(Ⅰ) and most probably incorporated into surface crystal lattice of the nano-sized PbTiO₃. In NO reaction, a large amount of oxygen atoms from the decomposition of NO penetrated into the nano-sized PbTiO₃ support and caused small expansion of crystal lattice. The transport of oxygen between the copper species and the catalyst support may be helpful to speed up the kinetic regeneration of active metal sites from oxygen occupancy and resulted in good catalytic performance.     

Crystal Structure of (6S,9S,13R,14S)-7,8-Didehydro-3,7-dimethoxy-17-methylmorphinan-4,6-diol

1 INTRODUCTION (9S,13R,14S)-7,8-Didehydro-3,7-dimethoxy-4-hydroxy-17-methylmorphinan-6-one I is an impor- tant natural product that was used to ease pain, decrease blood pressure and diminish inflammation. In order to study the stereochemistry of the reduction of I with potassium boronhydride, the crystal structure of the title compound II was determined by X-ray diffraction method. 2 EXPERIMENTAL 2. 1 Instrument The melting point was measured on a Yanagimoto MP-500 apparatus…     

Effect of carbon content on photocatalytic activity of C/TiO2 composite

A series of carbon-covered titania (CCT) were prepared via pyrolysis of sucrose highly dispersed on titania surface in flowing N₂. The samples were characterized by XRD, BET, DTA-TG, UV—Vis, and their photocatalytic properties were evaluated with two model pollutants, methylene blue (MB) and rhodamine B (RB), at room temperature. The effect of carbon content on photocatalytic activity of the C/TiO₂ composite was investigated. It was found that the effect of carbon content is different for different pollutants or different light sources. For three tested samples, under UV illumination CCT01 has the highest activity for MB photocatalytic degradation, while in the case of RB, CCT02 is the most active photocatalyst. Under visible light illumination, CCT005 has the highest activity for both MB and RB photocatalytic degradation. Translated from Chinese Journal of Catalysis, 2006, 27(1): (in Chinese)     

冻干保护剂溶液低温退火特性的研究

利用差示扫描量热仪(DSC)研究了10%叔丁醇/10%蔗糖/水溶液的冻结特性, 退火温度及退火时间, 分析了溶液的退火行为. 实验结果表明, 溶液降温时, 蔗糖的存在阻碍了叔丁醇析出, 最大冻结浓缩溶液玻璃化转变温度Tg′由－32.5 ℃降低到－42.0 ℃, 升温时在－30 ℃叔丁醇发生反玻璃化. 在反玻璃化峰附近的温度进行退火可使叔丁醇充分析出, Tg′由－42.0 ℃上升到－34.9 ℃. 所需的退火时间与退火温度有关, 退火温度越接近Tg′, 所需的退火时间越长. 在－37 ℃时, 退火20 min可完全消除反玻璃化.     

Scope and mechanistic study of the ruthenium-catalyzed ortho-C-H bond activation and cyclization reactions of arylamines with terminal alkynes

The cationic ruthenium hydride complex [(PCy(3))(2)(CO)(CH(3)CN)(2)RuH](+)BF(4)(-) was found to be a highly effective catalyst for the C-H bond activation reaction of arylamines and terminal alkynes. The regioselective catalytic synthesis of substituted quinoline and quinoxaline derivatives was achieved from the ortho-C-H bond activation reaction of arylamines and terminal alkynes by using the catalyst Ru(3)(CO)(12)/HBF(4).OEt(2). The normal isotope effect (k(CH)/k(CD) = 2.5) was observed for the reaction of C(6)H(5)NH(2) and C(6)D(5)NH(2) with propyne. A highly negative Hammett value (rho = -4.4) was obtained from the correlation of the relative rates from a series of meta-substituted anilines, m-XC(6)H(4)NH(2), with sigma(p) in the presence of Ru(3)(CO)(12)/HBF(4).OEt(2) (3 mol % Ru, 1:3 molar ratio). The deuterium labeling studies from the reactions of both indoline and acyclic arylamines with DCCPh showed that the alkyne C-H bond activation step is reversible. The crossover experiment from the reaction of 1-(2-amino-1-phenyl)pyrrole with DCCPh and HCCC(6)H(4)-p-OMe led to preferential deuterium incorporation to the phenyl-substituted quinoline product. A mechanism involving rate-determining ortho-C-H bond activation and intramolecular C-N bond formation steps via an unsaturated cationic ruthenium acetylide complex has been proposed.     

新型含吡啶基的不对称膦酸酯衍生物的合成与生物活性

通过2-氯-5-氯甲基吡啶与亚磷酸酯的Michaelis-Becker反应合成得到10个新型含吡啶基的不对称膦酸酯衍生物, 并对环状亚磷酸酯与2-氯-5-氯甲基吡啶反应的立体化学进行了研究, 结果表明: 不对称环状亚磷酸酯的电子效应和立体效应对反应的立体化学有着重要影响. 初步的生物活性结果表明, 该类化合物不具有杀虫活性, 但显现出较好的杀菌活性.     

Investigation on False Peak Phenomena in On-line Sweeping Technique in MEKC

ＩｎｔｒｏｄｕｃｔｉｏｎＭｉｃｅｌｌａｒｅｌｅｃｔｒｏｋｉｎｅｔｉｃｃｈｒｏｍａｔｏｇｒａｐｈｙ (ＭＥＫＣ)ｗａｓｉｎｖｅｎｔｅｄｔｏｅｘｔｅｎｄｔｈｅｕｔｉｌｉｔｙｏｆｃａｐｉｌｌａｒｙｅｌｅｃｔｒｏｐｈｏｒｅｓｉｓ(ＣＥ)ａｎｄｐｅｒｍｉｔｔｅｄｔｈｅｓｅｐａｒａｔｉｏｎａｎｄａｎａｌｙｓｉｓｏｆｎｅｕｔｒａｌｃｏｍｐｏｕｎｄｓ .ＢｕｔｊｕｓｔｌｉｋｅｏｔｈｅｒｍｏｄｅｓｏｆＣＥ ,ＭＥＫＣａｒｅｈａｍｐｅｒｅｄｂｙｔｈｅｌｏｗｃｏｎｃｅｎｔｒａｔｉｏｎｓｅｎｓｉｔｉｖｉｔｙｏｆｔｈｅｕｌｔｒａ …     

The effects of polymer chain rigidification, zeolite pore size and pore blockage on polyethersulfone (PES)-zeolite A mixed matrix membranes

The polyethersulfone (PES)-zeolite 3A, 4A and 5A mixed matrix membranes (MMMs) were fabricated with a modified solution-casting procedure at high temperatures close to the glass transition temperatures (T_g) of polymer materials. The effects of membrane preparation methodology, zeolite loading and pore size of zeolite on the gas separation performance of these mixed matrix membranes were studied. SEM results show the interface between polymer and zeolite in MMMs experiencing natural cooling is better (i.e., less defective) than that in MMMs experiencing immediate quenching. The increment of glass transition temperature (T_g) of MMMs with zeolite loading confirms the polymer chain rigidification induced by zeolite. The experimental results indicate that a higher zeolite loading results in a decrease in gas permeability and an increase in gas pair selectivity. The unmodified Maxwell model fails to correctly predict the permeability decrease induced by polymer chain rigidification near the zeolite surface and the partial pore blockage of zeolites by the polymer chains. A new modified Maxwell model is therefore proposed. It takes the combined effects of chain rigidification and partial pore blockage of zeolites into calculation. The new model shows much consistent permeability and selectivity predication with experimental data. Surprisingly, an increase in zeolite pore size from 3 to 5 Å generally not only increase gas permeability, but also gas pair selectivity. The O₂/N₂ selectivity of PES-zeolite 3A and PES-zeolite 4A membranes is very similar, while the O₂/N₂ selectivity of PES-zeolite 5A membranes is much higher. This implies the blockage may narrow a part of zeolite 5A pores to approximately 4 Å, which can discriminate the gas pair of O₂ and N₂, and narrow a part of zeolites 3A and 4A pores to smaller sizes. It is concluded that the partial pore blockage of zeolites by the polymer chains has equivalent or more influence on the separation properties of mixed matrix membranes compared with that of the polymer chain rigidification.