环境激素类物质2,4-二氯苯酚荧光免疫分析方法的建立

以2,4-二氯苯酚(DCP)与牛血清白蛋白的偶联物DCP-BSA为人工抗原,免疫新西兰大白兔,获得特异性的抗体.建立并优化了荧光免疫检测方法,工作曲线表明DCP在1～100 μg/L范围内呈良好的线性关系,回归方程为:IF=21.30lg ρ 29.13,相关系数r=0.991 5,DCP检出限为0.41 μg/L,抑制中质量浓度为9.18 μg/L,且对其它结构类似酚类化合物均有特异性识别.本法可应用于检测环境中微量的2,4-二氯苯酚.     

2,4-二氯苯酚的电化学氧化降解反应研究

采用循环伏安法和原位红外光谱技术研究了2,4-二氯苯酚在Pt电极上的电化学氧化降解反应,结合Fukui函数值预测了2,4-二氯苯酚在电化学氧化过程中的反应位点. 结果表明,Pt电极对2,4-二氯苯酚有良好的电催化活性,2,4-二氯苯酚在电极表面反应主要有3个途径：直接通过电化学反应脱去氯离子,生成苯酚;在·OH的进攻下,C—Cl键断裂,4位Cl较2位Cl先脱去,生成苯二酚,并可进一步氧化生成苯醌以及不饱和羧酸;在·OH的进攻下发生苯环开环反应,生成含氯不饱和羧酸. 在1700 mV左右,2,4-二氯苯酚可经电化学氧化生成CO₂.     

庚醛改性壳聚糖的制备及其对酚类化合物的吸附性能

在相转移催化剂存在下由庚醛与壳聚糖反应生成Schiff's碱,再用NaBH4 还原制备了N-烷基化壳聚糖衍生物,改性壳聚糖(CTS)产物的结构用FTIR和XRD进行了表征,研究了它对2,4-二氯酚的吸附性能. 考察了吸附时间、溶液pH值、2,4-二氯酚浓度和改性剂用量等因素对吸附的影响. 结果表明,改性CTS具有较好的抗酸碱性能;溶液的pH值对吸附的影响较大,在pH=6.0,吸附2 h时对2,4-二氯酚的吸附量最大,酚浓度对吸附的影响符合Freundlich吸附等温方程;改性壳聚糖对2,4-二氯酚的吸附性能明显优于未改性的CTS,对质量浓度为0.6 g/L的2,4-二氯酚溶液的吸附量分别为70.0和7.7 mg/g.     

担载CuO基催化剂上2,4-二氯酚的有效氧化降解

研究了2,4-二氯酚的催化氧化降解.结果表明,CuO/y-Al2O3催化剂表现出较高的活性,且碱土金属氧化物助剂的添加可进一步显著提高2,4-二氯酚氯离子的释放率,其中以SrO的促进作用最强,该催化剂循环使用3次,2,4-二氯酚转化率及氯离子的释放率均维持100％.X射线衍射和NH3程序升温脱附结果表明,催化剂上CuO...     

玻璃负载TiO2膜光催化降解2,4-二氯苯酚

玻璃负载TiO2膜光催化降解2;4-二氯苯酚     

The sorption properties of polymers with molecular imprints of 2,4-dichlorophenoxyacetic acid synthesized by various methods

New sorbents, polymers with molecular imprints of 2,4-dichlorophenoxyacetic acid (2,4-D), were prepared on the basis of acrylamide. The sorbents were synthesized by thermal polymerization methods with and without the use of ultrasound, photopolymerization, and suspension polymerization. The specific surface area of the products was estimated and their sorption properties were studied. Polymers with molecular imprints prepared by thermal polymerization with the use of ultrasound and by suspension polymerization showed the best ability to repeatedly bind 2,4-D. The selectivity of polymers was estimated for the example of structurally related compounds. It was shown that the method of synthesis decisively influenced not only the ability of sorbents to repeatedly bind 2,4-D but also their selectivity.     

Gas sorption in polymers based on bisphenol-A

Equilibrium gas sorption measurements for CO₂, CH₄, and N₂ were made with three polymers based on bisphenol-A, namely a polyhydroxyether, a polyetherimide, and a polyarylate. These data plus previous results for two other bisphenol-A polymers, polycarhonate and polysulfone, were analyzed using the dual-mode sorption model and the more recent gas-polymer-matrix model. The models were compared on the basis of physical interpretations of the resulting parameters. The Langmuir capacity from the dual-model model was related to the unrelaxed volume of the glassy polymer. The Henry's law sorption parameter from the dual-mode model was related to the internal pressure of the polymer and to its tensile stress at yield. The work suggests a means for estimation of gas sorption levels from thermal and mechanical properties of the polymer.     

Integral sorption in rubbery polymers

Simple equations are derived that describe integral sorption and desorption experiments under conditions where moving boundary effects in polymer films and spheres can be large because of high solvent concentrations. General conclusions are formulated about the nature of sorption and desorption experiments for both rectangular and spherical geometries. © 1998 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 36 : 171–180, 1998     

Organosoluble star polymers from a cyclodextrin core

Well‐defined star polymers were synthesized with a combination of the core‐first method and atom transfer radical polymerization. The control of the architecture of the macroinitiator based on β‐cyclodextrin bearing functional bromide groups was determined by ¹³C NMR, fast atom bombardment mass spectrometry, and elemental analysis. In a second step, the polymerization of the tert‐butyl acrylate monomer was optimized to avoid a star–star coupling reaction and allowed the synthesis of a well‐defined organosoluble polymer star. The determination of the macromolecular dimensions of these new star polymers by size exclusion chromatography/light scattering was in agreement with the structure of armed star polymers in a large range of predicted molecular weights. This article describes a new approach to polyelectrolyte star polymers by postmodification of poly(tert‐butyl acrylate) by acrylic arm hydrolysis in a water‐soluble system. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 5186–5194, 2005     

Branched supramolecular polymers formed by bifunctional cyclodextrin derivatives

Branched supramolecular polymers have been prepared from the mixture of 3-cinnamamide-α-CD (1) and 3-N^α-cinnamamidehexancarbonyl-N^?-cinnamamide-lysinamide-α-CD (3) and from the mixture of 3-cinnamamidehexanamide-α-CD (2) and 3. Compounds 1 and 2 formed a linear supramolecular polymer, whereas compound 3 having two guest moieties formed a hyperbranched supramolecular polymer. Physical properties of these supramolecular polymers were studied by viscosity measurements in aqueous solutions. When compound 3 was added to the solution of compound 2, the η_sp/C value of the mixture of 2 and 3 was found to be much higher than that of compound 2. These results indicate that compound 3 functions as a branching moiety to increase the viscosity. Supramolecular polymers consisting of compound 2 or 3 did not show the viscosity increase, whereas the mixture of 2 and 3 gave highly viscous solutions and formed fibers from the concentrated aqueous solutions. It is caused by the branching of linear supramolecular polymers with compound 3 and hydrophobic and/or hydrogen bonding interactions between supramolecular polymers.     

Adsorptive Stripping Voltammetric Determination of 2,4-Dichlorophenol by Laponite Modified Carbon Paste Electrode

A laponite modified carbon paste electrode was prepared, characterized and applied for the 2,4-dichlorophenol (2,4-DCP) voltammetric determination. It takes advantage of the ability of laponite to adsorb phenols, as well as of its availability and very low cost. Kinetic and equilibrium data for 2,4-DCP adsorption by laponite in aqueous dispersions demonstrated that the adsorption process obeyed a pseudo first order kinetic model and was consistent with the formation of adsorbed multilayers on a surface with heterogeneous pore distribution. The composite paste electrode exhibited a heterogeneous surface with 65 % increased surface area and 27 % enhanced catalytic activity compared to the unmodified one. The adsorptive stripping voltammetric determination of 2,4-DCP at an electrode with an optimized graphite:laponite ratio of 55 : 15 w% using a 3 min accumulation time at pH 5.5 was found to be suitable for its quantification in the linear concentration range extended up to 50 μmol L⁻¹ with a sensitivity of 0.56 μA L μmol⁻¹ and a LOD of 0.2 μmol L⁻¹ (S/N=3).The 2,4-DCP electrochemical response was not affected by the presence of some structurally similar phenols, like catechol and p-nitrophenol, while resorcinol, 2-chlorophenol, and 4-chlorophenol presented interferences. The results were validated by 2,4-DCP determination in spiked tap water.     

Phosphorus-containing cyclodextrin polymers: metal cations and hydroxyapatite affinities

The aim of this study was to highlight the properties of novel phosphorus-containing β-cyclodextrin polymers (CDP) and mainly their dual complexing abilities toward hydrophobic guests and (bio)minerals. Affinity of CDP toward divalent metal cations, calcium, magnesium and zinc, has been investigated by isothermal titration microcalorimetry (ITC). The complexation constants K were around 1.1–6.2 × 10⁴ L mol^?1 and were in the order Ca²⁺ < Mg²⁺ < Zn²⁺. The K regular increase with the CDP molecular weights could be attributed to a cooperative binding of the cations by the monophosphate groups carried by the CDPs. Regarding their CD and phosphorus functionalities, the dual complexing abilities toward amphiphilic guests and divalent cations can occur independently as evidenced from ITC experiments performed in presence of both species. Finally, strong interactions between CDPs and hydroxyapatite have been highlighted by X-ray photoelectron spectrometry with adsorbed amount in the range of 2 mg/m². CDPs are thus promising materials endowed with dual functionalities which could serve in biomaterials to simultaneously entrap bioactive molecules and capture (bio)minerals.     

Water soluble cyclodextrin polymers: Their interaction with drugs

The complex forming ability of a water-soluble -cyclodextrin epichlorohydrin, polymer (CDPS) and its different molecular weight fractions was studied and compared with the complexing properties of -cyclodextrin (CD) and dimethyl-CD (DM-CD). CDPS was separated into two main fractions. CDPS and its fractions formed well soluble inclusion compounds with the studied drugs. The low molecular weight fraction formed rather stable complexes with small guest molecules, the high molecular weight fraction was found to be more efficient in binding larger substrates. Structural studies of furosemide-CD complexes were attempted by NMR spectroscopy.Presented at the Fourth International Symposium on Inclusion Phenomena and the Third International Symposium on Cyclodextrins, Lancaster, U.K., 20–25 July 1986.     

Recent theories of gas sorption in polymers

Theories and models are presented for gas sorption in polymers above and below the glass transition temperature. With the exception of predictive theories that do not represent the data well, the models are fit to data for the carbon dioxide/silicone rubber and carbon dioxide/polycarbonate systems for the purposes of comparison. During the past decade, a number of new models and theories have been proposed specifically for gas sorption in glassy polymers. Each new model attempts to incorporate aspects of the gas sorption process that are unique to polymers below the glass transition temperature. This review discusses these recent advances, the assumptions used in their development and their advantages and disadvantages.     

Cationic-modified cyclodextrin nanosphere/anionic polymer as flocculation/sorption systems

Simultaneous removal of dissolved and colloidal substances has been a challenging task. The cationic-modified beta-cyclodextrin nanospheres synthesized in this work, in conjunction with a water-soluble polyacrylamide-based anionic polymer, potentially provide a novel approach to address the problem. The cyclodextrin was rendered cationic using (2,3-epoxypropyl)trimethylammonium chloride as a reagent. The cationicity of the modified cyclodextrin and the reaction between cyclodextrin and the reagent were characterized by electrophoresis measurement, polyelectrolyte titration, and NMR. As a dual-component flocculation system, the cationic cyclodextrin/anionic polymer significantly induced clay flocculation, lowering the relative turbidity of the clay suspension over a wide pH range. Meanwhile, as a nanospherical absorbent, the modified cyclodextrins exhibited strong affinity toward aromatic compounds via inclusion complex formation in the hydrophobic cavities, which was monitored by UV spectroscopy. These systems facilitated the simultaneous removal of dissolved and colloidal substances, which was unachievable previously. In addition, the interaction between anionic polymers and the clay particles pretreated with cationic cyclodextrin was investigated in order to reveal the flocculation mechanism.     

纳米级Pd/Fe双金属体系对水中2,4-二氯苯酚脱氯的催化作用

 利用化学沉淀法制备了纳米级Fe和纳米级Pd/Fe双金属催化剂,研究了它们对2,4-二氯苯酚(2,4-DCP)还原脱氯的催化性能. 结果表明,纳米级颗粒具有较高的比表面积和表面反应活性,其BET比表面积可达12.4 m2/g,当Pd/Fe用量为6 g/L时,2,4-DCP脱氯率达到90%以上. 脱氯效率与pH值、温度、钯含量和Pd/Fe投加量等因素有关. 2,4-DCP在脱氯过程中先生成2-氯苯酚和4-氯苯酚,最终生成苯酚,而少量的2,4-DCP可直接降解成苯酚.     

Drug loading in cyclodextrin polymers: dexamethasone model drug

In pharmaceutical formulations cyclodextrins (CDs) are used to improve the aqueous solubility, stability, dissolution rate, bioavailability and/or local tolerance of drugs. Moreover, water-soluble polymers can be used to stabilize drug/CD complexes through formation ternary complexes. Alternative approach is to use CD-polymers, which can both enhance the aqueous solubility of a drug and result in sustained drug release. The aim of this work was to compare the solubilizing effects of ternary drug/CD/polymer complexes with two novel high molecular weight CD-polymers, i.e. poly(ethylene glycol) based ??-cyclodextrin (??CD) polymer (PEG/??CD) and epichlorohydrin-??-cyclodextrin polymer (EPI/??CD) using dexamethasone (Dex) as a model drug, as well as the drug loading capacity of those selected CD-polymers. Hydroxypropyl methylcellulose and carboxymethylcellulose sodium salt were shown to have negligible effect on the solubilizing efficacy of ??CD while hexadimethrine bromide increases the solubilization efficacy. The stability of the polymers was tested and it was adequate for the experimental conditions used. The solubilization efficacy of both CD-polymers was higher than that of the parent ??CD and these ??CD based polymers are able to load greater amount of Dex than the parent ??CD.     

用量热滴定法研究2，4－二氯酚与吡啶的氢键络合反应

用量热滴定法研究２，４－二氯酚与吡啶的氢键络合反应李志伟，陈爱通，胡日恒（天津大学化学系，天津，３０００７２）（中国科学院化学研究所）关键词２，４－二氯酚，吡啶，正庚烷，氢键，量热滴定利用反应热测定样品滴定度是一种新兴的方法。在反应常数为１０３～１０...