负载型非晶态Cu/SiO2催化剂的非晶性质

以超细ＳｉＯ２为载体，用ＫＢＨ４还原Ｃｕ＾２＋盐溶液制备了非负载型Ｃｕ和负载型Ｃｕ／ＳｉＯ２催化剂，ＸＲＤ，ＴＥＭ和电子衍射分析结果表明，负载型Ｃｕ／ＳｉＯ２为完全非晶态，而非负载型Ｃｕ中存在着少量晶态Ｃｕ，ＤＳＣ结果表明，非晶态Ｃｕ／ＳｉＯ２的热稳定性明显高于非负载型Ｃｕ，说明超细ＳｉＯ２具有稳定非晶结构的作用，ＸＰＳ结果表明，还原产物中的铜原子呈Ｃｕ状态，ＩＣＰ分析结果表明，样品中的Ｂ含量均低     

硅胶负载钯催化剂对丙烯酸甲酯的催化加氢性能研究

本文报导一种新法制备的硅胶负载钯催化剂,其活性组份大部分负载于载体的表面。该催化剂在常温常压下对丙烯酸甲酯的液相加氢反应,即有很高的活性和良好的重复使用性能。 催化剂按下法制备:在圆底烧瓶中加入1.00g硅胶和20mL甲醇,抽真空置换出硅胶孔内的空气,在搅拌下加入一定浓度的吸附质(聚乙烯亚胺、正丙胺、正丁胺等),在25℃反应3—4小时,过滤,固体经甲醇充分洗涤后和一定浓度的氯化钯甲醇溶液反应6小时。过     

Synthesis and Characterization of Novel Organosoluble Methyl Substituted Poly(aryl Ether Ketone)s Containing Sulfone Linkage

Several new methyl substituted poly(aryl ether ketone)s containing sulfone linkage with inherent viscosities of 0.62–0.84 dL/g have been prepared from 4,4′‐bis(2‐methylphenoxy)diphenylsulfone and 4,4′‐bis(3‐methylphenoxy)diphenylsulfone with terephthaloyl chloride and isophthaloyl chloride by electrophilic Friedel‐Crafts acylation in the presence of DMF with anhydrous AlCl₃ as a catalyst in 1,2‐dichloroethane, respectively. These polymers having weight‐average molecular weight in the range of 71,000–49,000 are all amorphous and show high glass transition temperatures ranging from 167 °C to 191 °C, excellent thermal stability at temperatures over 400 °C in air or nitrogen, high char yields of 51–58% in nitrogen and good solubility in CHCl₃ and polar solvents such as DMF, DMSO and NMP at room temperature.     

Thallium-205 NMR spectroscopy. Solvation of the thallous ion in dilute aqueous-amide and amide-amide binary solvent systems of formamide,N-methylformamide,andN-ethylformamide

Solvation of the thallous ion in dilute solutions of six binary solvent systems (formamide/water,N-methylformamide/water,N-ethylformamide/water, formamide/N-methylformamide, formamide/N-ethylformamide, andN-methylformamide/N-ethylformamide) was studied with²⁰⁵Tl NMR spectroscopy. An attempt was made to separate solvation effects related to the electrondonating ability (Lewis basicity) of the solvents from effects resulting from structural changes in the solvation sphere. Structural effects were found to be greatest in theN-methylformamide/water system and least in theN-methylformamide/formamide system.     

PHOTOSENSITIVITY OF Ce (Ⅳ) INITIATED METHYL ACRYLATE POLYMERIZATION

The influences of UV light irradiation (313 nm) and diffused daylight on the polymerization of methyl acrylate initiated by the ceric ammonium nitrate without any reducing agent have been studied both in aqueous nitric acid and in pure water. The rate of polymerization was found to be accelerated and the overall activation energy and the induction time were found to be decreased sharply by the UV light irradiation. Under UV light, the rate of polymerization is 8 times as high as the rate in dark. The rate of polymerization was found to attain a maximum with the increase of nitric acid concentration and the rate of polymerization became less sensitive to UV light in the presence of nitric acid whereas the induction period reduced outstandingly. Based on the experimental results, the mechanism is proposed.     

引发甲基丙烯酸甲酯聚合的聚丙烯酰胺－氯化铜配合物膜催化剂表征

考察甲基丙烯酸甲酯在室温Ｎａ２ＳＯ３水溶液的聚合能力，发现在该溶液添加聚丙烯酰胺（ＰＡＡｍ）－氯化铜（ＣｕＣｌ２）配合物膜以组成ＰＡＡｍ－ＣｕＣｌ２膜／Ｎａ２ＳＯ３催化引发体系是必不可少的．采用ＥＳＲ、ＩＲ、ＸＰＳ和电导率等手段研究该体系催化剂的表面结构．结果表明，膜的单位面积平均含铜量在一定范围内和配位体种类等对催化活性有显著影响，即催化性能与催化剂的表面结构紧密相关．     

Methyl abstraction kinetics of CpFe(CO)2Me using the benzyl radical clock

The rate constant for the methyl abstraction reaction of CpFe(CO)₂Me has been measured with the benzyl radical clock as (1.1 ± 0.2) × 10⁵ M⁻¹ s⁻¹ at room temperature. Time-resolved Fourier-transform Infrared (FTIR) absorption spectroscopy pointed towards the formation of the CpFe(CO)₂ radical upon benzyl abstraction. The main stable product has been established by a linear scan of the reaction mixture as Cp₂Fe₂(CO)₄ produced by the dimerization of the CpFe(CO)₂ radicals. The transition state structure for the abstraction process was also found at UB3LYP/6-311+G* level of theory to contain a planar CH₃ group.     

Facile oxidative conversion of alcohols to esters using molecular iodine

A simple, efficient, and high-yield procedure for the oxidative conversion of alcohols to various types of esters and ketones, with molecular iodine and potassium carbonate was successfully carried out.     

Microemulsion photopolymerization of methacrylates stabilized with sodium dodecyl sulfate and poly(N-acetylethylenimine) macromonomers

Methyl methacrylate and butyl methacrylate were polymerized in oil-in-water microemulsions that were stabilized by sodium dodecyl sulphate (SDS). A poly(N-acetylethylenimine) (PNAEI) macromer was also included in the recipe, as a cosurfactant and a comonomer. Polymerizations were initiated by UV-irradiation. The average diameters of latex particles, obtained by STM, were in the range of 17-200 nm. The experimental data evidenced that the particle size was mainly dependent on the SDS/PNAEI ratio. Polymerization yields were around 75-85%. The synthesized copolymers have viscosity average molecular weights in the range of 2.1-2.4×10⁶ and glass transition temperatures of 38.0-43.5°C, lower than those obtained without using PNAEI. The investigation by means of FTIR and 1H-NMR techniques revealed that PNAEI was incorporated into the nanoparticles.     

Electrical conductivities of halide salts in aqueous formamide solutions

The electrical conductivities of sodium chloride and sodium iodide solutions in formamide-water mixtures of different composition have been measured at 25°C. From these data, the limiting equivalent conductances for these salts have been determined. The correspondingWalden products are compared together with the one reported for sodium bromide in the same solvent mixtures, and they are analysed as functions of the anion size. Further, the limiting ionic equivalent conductances are estimated for the different ions. The variation of the ionicWalden products with solvent composition is discussed in terms of ionic solvation and solvent structure.

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Elektrische Leitfähigkeit von Halogensalzen in wäßrigen Formamid-Lösungen

Zusammenfassung Es wurden die elektrischen Leitfähigkeiten von Natriumchlorid- und Natriumjodidlösungen in Formamid-Wasser-Mischungen verschiedener Zusammensetzung bei 25°C gemessen. Aus diesen Daten wurden die Grenzäquivalenzleitfähigkeiten für diese Salze bestimmt. Die entsprechendenWalden-Produkte wurden mit den für Natriumbromid in den gleichen Lösungsmittelgemischen berichteten verglichen und hinsichtlich der Anionengrößen analysiert. Außerdem wurden die ionischen Grenzäquivalenzleitfähigkeiten für die einzelnen Ionen abgeschätzt. Die Variation der ionischenWalden-Produkte mit der Lösungsmittelzusammensetzung wurde bezüglich Ionensolvatation und Lösungsmittelstruktur diskutiert.