活性酯固化邻甲酚环氧树脂反应机理的研究

采用交叉反应研究在促进剂2-甲基咪唑存在下活性酯固化邻甲酚环氧树脂的反 应机理，用傅立叶转换红外（FTIR）原位测量技术，NMR，气-质联用（GC-MS）等 手段研究了模型化合物的反应动力学，并提出了其反应机理。结果表明，在促进剂 2-甲基咪唑存在下活性酯固化邻甲酚环氧树脂的反应是通过分子内机理进行的。     

Sterically Hindered o‐Quinone Annulated with Dithiete: A Molecule Comprising Diolate and Dithiolate Coordination Sites

A new stable sterically hindered o‐quinone annelated with a 1,2‐dithiete ring was prepared by using mild conditions. The skeleton of the compound comprises diolate and dithiolate functions that have the potential to bind metals leading to the corresponding complexes. The reactivity of this compound as a ligand with respect to both coordination sites was studied. Reactions with metals indicate that the o‐quinone function is reduced in the first stage to give semiquinonate and catecholate complexes. The dithiolate coordination site was involved in the reaction in a few cases only after diolate was bound. A trinuclear manganese complex with coordination on both sites was obtained and characterized by EPR spectroscopy. The electrochemical study of this quinone fused with dithiete is reported.     

Response of protonic acid‐doped poly(o‐anisidine)/poly(vinyl alcohol) composites to relative humidity and role of dopant anions

Various protonated poly(o‐anisidine) (PoAN)/poly(vinyl alcohol) (PVA) composites were prepared with different types of acids: sulfuric (SA), p‐toluene sulfonic (TSA), camphor sulfonic (CSA), and p‐dodecylbenzene sulfonic (DBSA). In the visible spectrum of each composite in dimethyl sulfoxide, three absorption peaks were observed at 440, 620, and 860 nm. The peaks at 440 and 860 nm, which were enhanced with the increasing content of acid‐doped PoAN in the PVA matrix, were attributed to the radical cation and localized polaron generated in the conducting polymer. However, the peak at 620 nm was ascribed to the emeraldine base (EB) form of PoAN; that is, a portion of the acid was detached from the conducting polymer to form EB‐PoAN and free acid. The linear dependence of the logarithmic electrical conductivity on the variation of humidity, which was observed for all the composites, was caused by the salt–base transition of the conducting polymer, that is, by the movement of free acid between the active sites of the conducting polymer and the strongly bound water existing in PVA, which in turn depended directly on the environmental humidity. The response time of the composites to humidity was shortened with a decrease in the size of the dopant anions: DBSA > CSA > TSA > SA. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 4343–4352, 2000     

Positron annihilation studies of poly(N‐isopropyl acrylamide) gel in mixed solvents

Positron annihilation lifetime spectroscopy was used to characterize the reentrant volume‐phase‐transition behavior of poly(N‐isopropyl acrylamide) hydrogel in an ethanol/water mixed solvent. The polymer gel was synthesized with γ irradiation. The ortho‐positronium lifetime (τ₃) in the gel slowly increased with an increase in the ethanol content in the mixed solvent. τ₃ was not influenced by the volume phase transition. The ortho‐positronium intensity decreased with the collapse of the gel in an approximately 10% ethanol/water mixture. When swelled in pure ethanol, τ₃ initially increased with the solvent amount in the gel, showing the destruction of intramolecular hydrogen bonding and the relaxation of polymer chains. The lower critical solution temperature of the gel in the 10% ethanol/water mixture was lower than that in pure water, and τ₃ for various solvent contents showed behavior similar to that seen in pure solvent. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 1028–1036, 2002     

Synthesis,Characterization and Application of Some Axially Chiral Binaphthyl Phosphoric Acids in Asymmetric Mannich Reaction

Two novel chiral Br?nsted acids 3b and 3c were prepared without involving the complexity of Suzuki coupling. Catalyst 3c bearing two additional hydroxyl groups at 3 and 3′ positions of axially chiral 1,1‐binaphthalene‐2,2′‐diol phosphoric acid was applied in a model Mannich reaction to afford β‐amino ester in high yield (92%) and enantiomeric excess (91%) at low reacting temperature of ?40°C. In addition, those β‐amino ester derivatives with high yields and excellent enatioselectivities were obtained in the presence of catalyst 3c under the above condition.     

取代邻苯二腈的合成

在室温条件下合成了一系列芳氧基邻苯二腈化合物,应用无素分析、1HNMR、IR确定了它们的结构,讨论了不同取代基对反应的影响.结果表明,酚的芳环上有推电子基时反应容易进行;酚的芳环上有拉电子基时反应慢或不反应.     

稀土固体超强酸SO_4~(2-)/TiO_2-La~(3+)催化硝化甲苯的研究

研究了以固体超强酸SO24-/TiO2-La3+作为催化剂,浓硝酸和甲苯为原料合成硝基甲苯,并考察了影响反应的因素。结果表明,催化剂用浓度为1.0 mol.L-1硫酸浸泡3小时,反应催化剂用量为硝酸质量的10%,反应时间为3小时,反应温度为55℃是最适宜的反应条件,甲苯转化率达90.14%,邻对比达0.89。     

A New Amperometric Biosensor Based on HRP/Nano-Au/L-Cysteine/Poly（o-Aminobenzoic acid）-Membrane-Modified Platinum Electrode for the Determination of Hydrogen Peroxide

The third generation amperometric biosensor for the determination of hydrogen peroxide （H2O2） has been described. For the fabrication of biosensor, o-aminobenzoic acid （oABA） was first electropolymerized on the surface of platinum （Pt） electrode as an electrostatic repulsion layer to reject interferences. Horseradish peroxidase （HRP） absorbed by nano-scaled particulate gold （nano-Au） was immobilized on the electrode modified with polymerized o-aminobenzoic acid （poABA） with L-cysteine as a linker to prepare a biosensor for the detection of H2O2. Amperometric detection of H2O2 was realized at a potential of ＋20 mV versus SCE. The resulting biosensor exhibited fast response, excellent reproducibility and sensibility, expanded linear range and low interferences. Temperature and pH dependence and stability of the sensor were investigated. The optimal sensor gave a linear response in the range of 2.99×10^-6 to 3.55×10^-3 mol·L^-1 to H2O2 with a sensibility of 0.0177 A·L^-1·mol^-1 and a detection limit （S/N = 3） of 4.3×10^-7 mol·L^-1. The biosensor demonstrated a 95% response within less than 10 s.     

Elastic Behavior of Polymer Chains

The elastic behavior of the polymer chain was investigated in a three-dimensional off-lattice model. We sample more than 109 conformations of each kind of polymer chain by using a Monte Carlo algorithm, then analyze them with the non-Gaussian theory of rubberlike elasticity, and end with a statistical study. Through observing the effect of the chain flexibility and the stretching ratio on the mean-square end-to-end distance, the average energy, the average Helmholtz free energy, the elastic force, the contribution of energy to the elastic force, and the entropy contribution to elastic force of the polymer chain, we find that a rigid polymer chain is much easier to stretch than a flexible polymer chain. Also, a rigid polymer chain will become difficult to stretch only at a quite high stretching ratio because of the effect of the entropy contribution. These results of our simulation calculation may explain some of the macroscopic phenomena of polymer and biomacromolecular elasticity.     

Adsorption of aqueous Hg (II) by a novel poly(aniline‐co‐o‐aminophenol)/mesoporous silica SBA‐15 composite

A novel poly(aniline‐co‐o‐aminophenol) (PAOA)/mesoporous silica SBA‐15 nanocomposite was synthesized and investigated for adsorption of Hg (II) from aqueous solutions of wide pH range. A chemical oxidation method was employed for polymerization of aniline and o‐aminophenol on an ordered SBA‐15 template to obtain a significantly enlarged BET surface area of the adsorbent. Efficiency study revealed that the PAOA/SBA‐15 could reach a maximum Hg (II) adsorption capacity of over 400 mg/g. Kinetic study showed that the Hg (II) adsorption by the PAOA/SBA‐15 fitted a pseudo‐second‐order kinetic model, indicating that the mercury adsorption process was predominantly controlled by chemical process. The results of this study also proved that the adsorbed Hg (II) could be effectively desorbed from the PAOA/SBA‐15 in 0.1M HCl and 5% sulfocarbonide solutions. Associated adsorption mechanism was also investigated by means of Fourier transform infrared (FTIR) and X‐ray photoelectron spectroscopy (XPS) techniques. Copyright © 2010 John Wiley & Sons, Ltd.