Pressure Effects in the Solvolysis of Benzyl Chlorides

Rates of solvolysis of benzyl chloride and of substituted benzyl chlorides have been measured in an acetone-water mixture (acetone mole fraction 0.147) at pressures ranging from atmospheric to 1 kbar. Pressure studies have also been made for p-methyl benzyl chloride in various acetone-water mixtures. Measurements have also been made of the partial molar volumes of the reactants. The plots of log k against pressure are fitted to a second-degree polynomial in P, and values of ΔV^? and (δΔV^//δP)_T are obtained. The ΔV^? values are all negative, having values ranging from ?18 to ?24 cc/mole. The results are interpreted on the view that the mechanisms are S_N2(1), i.e. are towards the S_N1 end of the S_N2 spectrum of behavior. The ΔV^? values steadily become more negative in the series p? CH₃, H, p? Cl, pNO₂, and this is interpreted in terms of the greater spreading of positive charge in the p? CH₃ case and in terms of greater S_N2(2) character in the p? NO₂ case. The ΔV^? values go through a minimum as the solvent composition is varied, a result that is related to the existence of a corresponding maximum in the partial molar volumes of the reactant. The (δΔV^?/δP)_T values show a negative correlation with ΔV^?, suggesting, as expected, that the more compact activated complexes are the least compressible.     

木质素磺酸钠改性聚砜膜的制备及其在正渗透膜中的应用

采用木质素磺酸钠作为亲水添加剂,通过浸没沉淀相转化法制备了木质素磺酸钠共混改性聚砜膜,以改善聚砜膜的亲水性,并用作正渗透膜的支撑层,以降低内浓差极化效应.利用扫描电子显微镜、衰减全反射傅里叶变换红外光谱仪、水接触角仪等研究了不同木质素磺酸钠添加量对聚砜膜的结构和表面性质的影响.结果表明,添加木质素磺酸钠后,聚砜膜的指状孔变得规整且狭长.水接触角实验证实添加木质素磺酸钠能改善聚砜膜的亲水性,当木质素磺酸钠含量为0.4 wt%时,聚砜膜的表面水接触角可降低至65°.正/反渗透测试装置分别用于表征正渗透膜的传质性质和结构参数.结果表明,以0.4 wt%木质素磺酸钠改性聚砜膜为支撑层的正渗透膜的水渗透性能(A=3.12×10~(-5) LMH×Pa~(-1))优于纯聚砜基底正渗透膜(0.76×10~(-5)LMH×Pa~(-1)),而且前者的结构参数(S=2010mm)远小于后者(3450mm),说明木质素磺酸钠改性聚砜膜有效弱化了正渗透膜的内浓差极化效应.     

Study of the Reaction of Hydroxybenzoyl Chlorides and Their Derivatives with Imidazole

Russian Journal of Organic Chemistry - The reaction of hydroxybenzoyl chlorides with imidazole was studied on an example of the Schotten-Baumann reaction of salicyloyl and acetylsalicyloyl...     

氯化-甘氨酸六水合稀土固体络合物的合成及红外光谱研究

本文用稀土氯化物与甘氨酸反应制备了标题络合物[Ln(Gly)·6H_2O]·Cl_3(Ln=Nd,Sm,Gd,Er,Yb),测定了络合物的红外光谱,对其主要吸收带进行了归属。红外光谱的研究结果表明,甘氨酸以内盐的形式存在于络合物中,通过羧基与稀土离子配位。水分子也参与了配位。并推测,Nd的络合物为双核络合物,其它稀土络合物具有一维无限长链结构。     

Calculation of Conditional Equilibrium Constants of Reactions of Reduction of Titanium,Zirconium, and Hafnium Chlorides with Alkali Metals in a Melt of Their Chlorides

Equilibrium constants of the reactions of reduction of Ti, Zr, and Hf chlorides with metallic Li, Na, K, Rb, and Cs in their molten chlorides were calculated from published data.     

Reaction of Chlorine in Aqueous Solution with Hydrolysis Lignin under Elevated Pressure

Chlorination and oxidation of hydrolysis lignin with chlorine in aqueous solution under elevated pressure was studied with the aim to intensify the process.     

污泥碳基催化材料的合成及在水环境中的应用

污泥是城市污水处理厂的副产物,是一种典型的固体废弃物,具有污染与资源的双重属性。以污泥作为原材料制备碳基催化材料并用于水环境催化是一种新型的污泥减量化和资源化利用方式。由于污泥是生物质有机质和多种无机氧化物、金属离子的混合物,因此以其制备的碳基催化剂或载体材料具有原料易得、活性位点分散、表面化学官能团易于调控、比表面积高等特点,并被广泛地用于多相Fenton催化、电催化、光催化、湿式氧化和臭氧氧化等水环境催化领域。本文将阐述污泥碳基催化剂材料的制备和改性方法,通过材料物理、化学性质与催化作用的构效关系并结合其在水环境催化领域的应用特点,说明碳基催化剂参与水中污染物吸附、电子转移和有机物降解的作用机制,同时对提高污泥基材料的稳定性、可重复利用性和催化活性提出新的展望。     

纳米木质素/二氧化硅基微胶囊的制备及在自愈合涂层中的应用

利用磷酸化改性木质素/二氧化硅复合纳米颗粒(PAL/SiO₂)作为壁材包埋活性组分异佛尔酮二异氰酸酯(IPDI)制备微胶囊(PAL/SiO₂-IPDI). 通过加入少量反应活性更高的聚合多甲基多二异氰酸酯(PMDI), 与水反应形成聚脲, 以增加微胶囊的壁厚. 采用光学显微镜、 扫描电子显微镜(SEM)和激光粒度分析仪(DLS)研究了PAL/SiO₂复合纳米粒子掺杂量, 水油比和剪切速率对微胶囊表面形貌、 粒径和壁厚的影响. 结果表明, 所制备的微胶囊呈现规整球形, 壁厚为2.36~3.50 μm, 平均粒径为40.3~201.5 μm. IPDI作为芯材包埋在微胶囊中, 芯材含量约为82.8%. 将制备的PAL/SiO₂-IPDI微胶囊添加到环氧树脂中得到自愈合环氧树脂涂层. 其在高盐浓度溶液中的抗侵蚀测试结果显示, 添加质量分数4%的PAL/SiO₂-IPDI微胶囊的环氧树脂涂层在划破后能够快速愈合, 显著降低基底的腐蚀电流和腐蚀速率. 纳米压痕实验表明, 环氧涂层的硬度为249.99 MPa, 而添加PAL/SiO₂-IPDI微胶囊后硬度增加到302.98 MPa, 弹性模量也有提高.     

Polymer-Protected Palladium Nanoparticles and Their Use in Catalysis

Abstract

Stable palladium colloids were prepared by the in-situ reduction of palladium chloride (PdCl₂) in the presence of protective water-soluble polymers and cationic polyelectrolytes. The particle sizes, morphologies, and particle-size distributions were determined by transmission electron microscopy and found to be in the nanometer size range. The catalytic activity of these colloidal metal-polymer systems was tested by the hydrogenation of cyclohexene as a model reaction. Most of the polymer-protected palladium nanoparticles were found to be catalytically active, and final conversions up to 100% were obtained in many cases.     

Properties of Carbon Materials and Their Use in Chromatography

Sorption properties of graphite, fullerene, and nanotubes were considered, as well as the pattern of variation of the sorption properties of fullerene C60 in complexing with various macrocycles. The use of these materials as stationary phase in chromatography and in solid-phase concentration of microimpurities of aromatic hydrocarbons was discussed.     

Interaction of Hafnium Chlorides with Magnesium,Aluminum, and Lead in Molten Alkali Metal Chlorides

The thermodynamic characteristics of the interaction of hafnium(II) and hafnium(IV) chlorides with magnesium, aluminum, and lead in molten alkali metal chlorides were calculated.     

离子色谱法测定沉积物中氯

采用艾斯卡试剂烧结法对沉积物样品进行分解,用离子色谱法分离测定沉积物中氯含量。以IonPacAG11型保护柱和IonPacAS11-HC型分离柱分离,以25mmol.L-1氢氧化钠溶液为淋洗液等度洗脱。方法的检出限(3s)为8μg.g-1。方法用于黄河三角洲沉积物标准物质(GBW 07343,GBW 07344和GBW 07345)的分析,测定值与认定值相一致。     

四级铵基取代羧酸转化为酰氯的探试

绝大多数Schotten-Baumann酰化^[1]在两相间发生,为探究在单相水介质中合成酰胺的效率,我们企图对几个典型的羧酸引入四级铵基,以制备结晶的水溶性酰氯.     

Abrasive Stripping Voltammetric Studies of Lignin and Lignin Model Compounds

Lignin is potentially a major renewable, nonfossil source of aromatic and cyclohexyl compounds. In this study, we have investigated the abrasive stripping voltammetry of lignin and four lignin model compounds in the room temperature ionic liquids (RTILs) [C₄mim][NTf₂], [N_6,2,2,2][NTf₂] and [C₄mim][OTf] (where [C₄mim]⁺=1‐butyl‐3‐methylimidazolium, [N_6,2,2,2]⁺=n‐hexyltriethylammonium, [NTf₂]^?=bis(trifluoromethanesulfonyl)imide and [OTf]^? =trifluoromethanesulfonate) on a gold macrodisk and in 0.1 M H₂SO₄ and 0.1 M NaOH on a boron‐doped diamond (BDD) macroelectrode, with the hope of using the voltammetry to fingerprint the functional groups within the lignin molecule. The use of RTILs on metal electrodes, or either acidic or basic media in combination with BDD electrodes allows solvent systems with wide electrochemical potential windows, useful for studying voltammetry which may be difficult to observe in systems where early breakdown of the solvent occurs.     

On the Use of Atmospheric Pressure Plasma for the Bio-Decontamination of Polymers and Its Impact on Their Chemical and Morphological Surface Properties

Low temperature atmospheric pressure plasma processes can be applied to inactivate micro-organisms on products and devices made from synthetic and natural polymers. This study shows that even a short-time exposure to Ar or Ar/O₂ plasma of an atmospheric pressure plasma jet leads to an inactivation of Bacillus atrophaeus spores with a maximum reduction of 4 orders of magnitude. However, changes in the surface properties of the plasma exposed material have to be considered, too. Therefore, polyethylene and polystyrene are used as exemplary substrate materials to investigate the effect of plasma treatment in more detail. The influence of process parameters, such as type of operating gas or jet-nozzle to substrate distance, is examined. The results show that short-time plasma treatment with Ar and Ar/O₂ affects the surface wettability due to the introduction of polar groups as proofed by X-ray photoelectron spectroscopy. Furthermore, atomic force microscopy images reveal changes in the surface topography. Thus, nanostructures of different heights are observed on the polymeric surface depending on the treatment time and type of process gas.     

Selectivity of Transport of Sodium, Magnesium, and Calcium Ions through a Sulfo-Cationite Membrane in Mixtures of Solutions of Their Chlorides

The transport numbers and the selectivity of transport of sodium, magnesium, and calcium ions through a heterogeneous sulfo-cationite membrane in solutions of sodium, magnesium, and calcium chlorides and their mixtures are studied at various current densities. Equations for calculating the selectivity of transport of the ions through the membrane are suggested for two extreme cases. One case corresponds to low currents, when one can assume that the membrane is at equilibrium with the outside solution. The selectivity of transport of the ions is defined in this case by their migration through the membrane. The other case occurs at currents that are close to a limiting value. Under these conditions the transport of the ions through the membrane is defined by their transport through a diffusion layer that forms near the membrane surface. Calculations with the aid of these equations satisfactorily conform to experiment. The deviation from calculation in the case of the magnesium cation is connected probably with its hydration being substantially greater as compared with sodium and calcium. It is established that the selectivity of transport of the ions through the membrane may be controlled to a certain extent by varying the current density.__________Translated from Elektrokhimiya, Vol. 41, No. 8, 2005, pp. 997–1000.Original Russian Text Copyright © 2005 by Greben’, Rodzik.     

丹参木质素及其单体含量的测定

本文建立了一种准确、快速的检测丹参中木质素及其单体含量的方法.采用Klason法和紫外分光光度法分别对丹参根和茎中酸不溶性木质素(Klason木质素)和酸溶性木质素含量进行了测定;运用硫代酸解法并结合气相色谱-质谱法(GC-MS)分别对丹参根和茎中各木质素单体组成进行了分析.结果显示,总木质素在丹参根和茎中的含量分别为...