酸促进的氨基甲酸酯醇解合成碳酸酯

在较低温度和压力下,以氯化氢为共反应物或沸石分子筛为催化剂,由氨基甲酸酯与醇反应合成多种碳酸酯。氯化铵沉淀的生成或沸石分子筛对氨气的吸附,可推动反应平衡,使碳酸酯的生成达到较高收率。以氯化氢为共反应物时,反应温度为60℃,最高产率达58％;而以沸石分子筛为催化剂,反应温度为140℃时,最高产率是19％。     

不同光敏剂对光敏热成像材料感光性能的影响

本文考察了不同制备方法、不同种类的光敏剂对以苯并三氮唑银为银源的光敏热成像材料感光性能的影响。结果显示原位法中以AgI和AgBrI为光敏剂的PTG材料具有较高的感光度,分别为以AgBr为光敏剂的参比样片感光度的16倍和2.4倍;异位法制备的PTG材料中,以AgBrI乳剂为光敏剂的感光度比以AgBr为光敏剂的感光度高,是其3倍;此外,同是以AgBr为光敏剂、用异位法制备的PTG材料的感光度比原位法制备的PTG材料感光度高。文中初步分析讨论了出现以上实验结果的原因。     

Application of chitosan matrix for delivery of rutin

Chitosan matrices are an alternative material to the food industry, due to its ability to release bioactive compounds through interconnected cavities. Chitosan is a biomaterial of excellence, because it shows unique features, such as biocompatibility, non-toxicity, bactericidal action and the ability to associate with other compounds. Thus, this study aimed the development of chitosan matrices incorporated with rutin, as well as the evaluation of rutin release. Chitosan matrices with rutin were prepared by the coacervation method in alkaline solution and subsequently characterized through FT-IR, TG-DSC, X-ray diffraction, SEM and further submitted to rutin release assay. Results show the effectiveness in the incorporation of rutin into the polymeric matrix. The polymeric matrix with rutin can quickly release it, which provides a wide range of applications, such as carrier of rutin as a micronutrient food additive.     

Optimization of capillary electrophoretic-electrospray ionization-mass spectrometric analysis of catecholamines

The capillary electrophoretic-mass spectrometric analysis (CE-MS) of catecholamines was optimized with coaxial sheath flow interface and electrospray ionization (ESI). The parameters studied included the sheath liquid composition and its flow rate, separation conditions in ammonium acetate buffer together with the ESI and cone voltages as mass spectrometric parameters. In addition, the effect of ESI voltage on injection as well as the siphoning effect were considered. The optimized conditions were a sheath liquid composition of methanol-water (80:20 v/v) with 0.5% acetic acid, with a flow rate of 6 microL/min. The capillary electrophoretic separation parameters were optimized with 50 mM ammonium acetate buffer, pH 4.0, to +25 kV separation voltage together with a pressure of 0.1 psi. The most intensive signals were obtained with an ESI voltage of +4.0 kV and a cone voltage of +20 V. The nonactive ESI voltage during injection as well as avoidance of the siphoning effect increased the sensitivity of the MS detection considerably. The use of ammonium hydroxide as the CE capillary conditioning solution instead of sodium hydroxide did not affect the CE-MS performance, but allowed the conditioning of the capillary between analyses to be performed in the MS without contaminating the ion source.     

Gamma radiolysis of an aqueous anthraquinone dye solution in the presence of oxygen

Experiments with Acid Blue 62 as a model compound for dyes were performed under steady-state conditions, using deoxygenated solutions as well as those saturated with N₂O, oxygen or oxygen mixed with N₂O. The yield of decoloration served as an indicator for the degradation process. Oxygen seems to inhibit radiation-induced decomposition of the dye in aqueous solution.     

Termochemistry of Aniline Solution in Mixtures of Alcohols with Dihexyl Ether

The heats of solution of aniline and cyclohexane in mixtures of methanol, 1-butanol, and 1-octanol with dihexyl ether at 25°C in the entire range of compositions of the mixed solvents were measured. The enthalpies of transfer of aniline and cyclohexane from dihexyl ether to its mixtures with alcohols were calculated. It was suggested that, in methanol-based systems, the major factor is the interaction of the alcohol as an acid with aniline as a base, whereas in butanol- and octanol-based system the larger contribution is made by the interaction of the alcohol as a base with aniline as an acid.     

光照对高铁酸盐溶液稳定性的影响

The effects of light wave on the stability of fen'ate solution have been examined. The results showed that UV-light accelerates the decomposition of ferrate with decomposition rate 1.6 times as much as that in dark whereas infrared light has only unclear effect on the stability of ferrate, with decomposition rate 1.1 times as much as in dark. The polythene container is found to the best for preservation of ferrate solution in dark.     

Determination of impurities in tungsten metal: Determination of iron

A method is proposed for the determination of iron present as an impurity in tungsten. 4,7-diphenyl-1,10-phenanthroline forms a stable complex with iron (present as the ferrous ion) which can be extracted by chloroform, in presence of alcohol, and determined absorptiometrically. Tungsten is complexed as citrate, and iron is reduced with sodium dithionite.     

Biochemistry of anionic calix[n]arenes

This review treats the biological properties of the various anionic calix[n]arenes, both as soluble forms and in the colloidal state. The complexation of these molecules with amino-acids, peptides and proteins is discussed, as is their interaction with model membranes. The complexations with various Active Pharmaceutical Ingredients as complexes, for tamoxifen as solid state and colloidal structures, are treated in depth. Two sections deal with the direct biological action of the calix[n]arenes and their use as biosensors. A final section deals with the toxicity, in reality the lack of toxicity of the calix[n]arenes.     

Bulk and surface modifications of polylactide

This article reviews various methods of modifying the bulk and surface properties of poly(lactic acid) (PLA) so that the polymer may be used as a drug carrier in a drug delivery system (DDS) and as a cell scaffold in tissue engineering. Copolymerization of lactide with other lactone-type monomers or monomers with functional groups such as malic acid, copolymerization of lactide with macromolecular monomer such as poly(ethylene glycol) (PEG) or dextran, as well as blending polylactide and natural derivatives and other methods of bulk modification are discussed. Surface modifications of PLA-type copolymers, such as surface coating, chemical modification, and plasma treatment are described. Cell culture technology proves the efficiency of bulk and surface modification and the potential application of PLA in tissue engineering.     

Effect of surface parameters on the performance of IgG-arrayed hydrogel chips: a comprehensive study

In this article, the assay performance of 3D polyurethane (PU) hydrogel surfaces, used either plain or modified with cross linkers and additives in a direct immunoassay for IgG, is correlated with chip surface parameters such as water content and expansion, mechanical stability, hydrophilicity, thickness, and surface topography. Commercial chip surfaces ARChip Epoxy, Nexterion slide H and HydroGel are used as references. A strong correlation between assay sensitivity and physical surface parameters was found only for various hydrogels of the same chemical composition, in which cases assay sensitivity increases with decreasing hydrogel concentration as well as decreasing roughness, water content, and expansion. However, as is the case with all hydrogels tested, more hydrophobic layers with low water content are more highly reproducible from one measurement to another.     

Studies of physicochemical properties of the surfaces with the chemically bonded phase of BSA

The paper presents the method of preparation and determination of physicochemical properties of silica gels with a chemically bonded BSA phase as well as studies of the effect of support porosity on the synthesis. Wide-porous Z-300 and narrow-porous Z-100 silica gels were studied. The investigations showed a significant effect of pore size on the synthesis of stationary phases with BSA. Modification with protein results in changes of adsorption properties and porosity of adsorbent samples. Changes of physicochemical properties result in significant changes of geometrical and structural heterogeneity of the support (specific surface area, fractal coefficient) as well as energetic heterogeneity of the samples. This revised version was published online in July 2006 with corrections to the Cover Date.     

Study of plant coumarins 1. Transformations of peucedanin

The structure of 2-bromooreoselon, which was prepared by bromination of peucedanin or oreoselon with molecular bromine, was established. The compositions and structures of the reaction products of this bromide with amines, such as pyridine, triethylamine, and morpholine, as well as with sodium acetate and potassium hydroxide were studied. The reaction of peucedanin with m-chloroperoxybenzoic acid affords peuruthenicin isobutyrate. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 362—366, February, 2006.     

双氧水氧化环己烯催化合成己二酸研究进展

评述了近年来以环己烯为底物,双氧水为氧源,分别采用钨酸盐、钨酸、杂多酸及杂多酸盐、功能化分子筛和负载离子液体等为催化剂催化合成己二酸的研究进展.     

Evaluation of the performance of single‐walled carbon nanohorns in capillary electrophoresis

This paper describes for the first time the use of single‐walled carbon nanohorns (SWNHs) as pseudostationary and stationary phases for EKC and CEC, respectively, taking advantage of their characteristic features, such as conical‐end termination, formation of spherical assemblies dahlia‐flower like superstructure and easy functionalization. The use of SWNHs as pseudostationary phase for EKC required the study of their dispersion in different surfactants as well as their compatibility with the electrophoretic system. The carboxylation and subsequent immobilization of carboxylated SWNHs in fused‐silica capillary to obtain useful, reproducible and stable stationary phases for CEC has also been investigated, with promising results. The electrophoretic separations obtained for water‐soluble vitamins in both modalities (EKC and CEC) have been systematically compared with those obtained with single‐walled carbon nanotubes.     

含有机硅三元多嵌段共聚物的研究──Ⅲ．不同硬段、半硬段对含有机硅三元多嵌段共聚物性能的影响

以双酚Ａ聚砜或酚酞作为硬段，聚对羟基苯乙烯、酚醛、聚羟基醚或聚羟基醚砜作为半硬段，聚二甲基硅氧烷作为软段合成了七种三元多嵌段共聚物，并对其稳定性、动态力学性能进行了比较详细的研究。结果表明这类共聚物在溶液中的稳定性及热稳定性主要与半硬段有关；它们的形态结构同属于微相分离，并在很宽的温度范围内表现出优良的弹性体性质。三元多嵌段共聚物中硬段与半硬段的相容性直接影响其力学性能，当两者的相容性好时，其强度高于对应的二元多嵌段共聚物。     

Formylation of Secondary Amines with Dialkyl Acetals of Dimethylformamide

Abstract

The product of the reaction of dialkyl acetals of N, N-dimethyl-formamide with desipramine has been found to be N-formyldesipramine, and not the N-ethyl derivative as reported earlier. Evidence for the structure was obtained from NMR, IR and mass spectra of the compound as well as comparison with N-formyl and N-ethyldesipramine prepared by alternate routes.     

Contribution to the basic problems of complexometry—III Some advantages of acetate buffer

Acetate buffer, in conjunction with additives such as o-phenanthroline or :'-bipyridyl, permits the titration of metallic cations such as copper with EDTA in weakly acid medium, using Xylenol Orange of Methyl Thymol Blue as indicators. In this it is superior as a buffer to the more generally used urotropine. The nature of its action is discussed.     

Reaction of thiocyanates with ironcyanogen compounds of silver

Silver fenocyanide as well as Silver ferricyanide are converted into silver thiocyanate by treating with thiocyanate ions, while feirocyanide ions or ferricyanide ions are formed at the same time. Silver ferrocyanide as well as silver ferricyanide are dissolved by solutions of thiocynates of higher concentrations.     

烯丙位氧化的几种方法

综述了近年来烯丙位氧化的研究进展，详细讨论了过渡金属及其络合物、硒化 合物在烯丙位氧化中的应用，并简述了丁基锂方法、固相催化方法、生物氧化方法 和次氯酸钠氧化方法在烯丙位氧化中的应用．