β-环糊精在有机合成中的应用研究进展

β-环糊精因具有酶的性质,提供内腔疏水的环境,包结有机分子形成了复合物,使许多反应在温和的条件下就有良好的产率。本文综述了β-环糊精在有机合成方面的应用。     

环糊精衍生物的分子形态及其构筑策略研究进展

根据环糊精衍生物分子结构与形态的不同,分类综述了环糊精衍生物（以β-环糊精衍生物为主）的形态及其构筑策略研究进展,包括单取代环糊精衍生物、双取代环糊精衍生物、多取代环糊精衍生物、二聚体环糊精衍生物、多聚体环糊精衍生物和环糊精聚合物（包括固载化环糊精）。指出环糊精衍生物的构筑是基于环糊精构筑各种功能材料的基础与关键,是环糊精母体应用的进一步拓展。基于环糊精构筑各种超分子仿酶,不仅可以充分发挥环糊精结构上的先天优势,也可以实现有机合成反应从有机相到水相的顺利过渡,并提高反应的选择性,对有机合成化学的"绿色化"具有重要的意义,对其他功能材料的构筑也具有重要的参考价值和指导意义。     

环糊精及其衍生物在有机合成中的应用

综述了环糊精及其衍生物在各种有机化学反应中的应用,包括氧化、还原、取代、加成、光催化反应。最后从有机绿色合成的角度,展望了环糊精在有机合成的发展方向。     

环糊精及其衍生物在有机合成中的应用

综述了环糊精及其衍生物在各种有机化学反应中的应用,包括氧化、还原、取代、加成、光催化反应。最后从有机绿色合成的角度,展望了环糊精在有机合成的发展方向。     

β-环糊精在液相合成反应中的应用

综述了β-环糊精应用于液相反应研究的最新进展,对β-环糊精作为催化剂或反应载体进行开环、氧化、脱保护等反应进行分类阐述,包括对β-环糊精的反应底物选择性能和催化性能进行分析,认为β-环糊精与底物的相互作用可有效地催化液相有机化学反应,提高反应选择性。提出β-环糊精尤其是β-环糊精衍生物在有机合成反应中将具有广阔的发展前景。     

环糊精包合物

环糊精(Cyclodextrin,简称CD)是一种水溶性、非还原性、不易被酸水解的白色晶体,无毒,可食用,具有多孔性,它是由环糊精糖基转移酶作用于淀粉或直链环糊精而形成的一类环状低聚糖。常见的环糊精是由6个、7个或8个葡萄糖单元以1,4-糖苷键结合而成的α-CD、β-CD以及γ-CD3种。环糊精分子内的手性空腔具有不对称诱导、选择结合和催化某些有机反应的特性,可以作为受体借助分子间相互作用制备包合物,以改变这些化合物的物理化学性质,因此,环糊精包合物已广泛应用于制药、分析化学、环保、有机合成、食品等诸多领域。1环糊精的结构经结构分析…     

丙二腈在有机合成中的应用研究进展

丙二腈分子中具有多个反应活性中心,是设计合成结构复杂多样的有机分子的理想原料。丙二腈参与的反应在具有重要生理和药理活性的杂环和碳环骨架的构筑中发挥着重要作用,在化学、医药和材料科学领域得到了广泛的应用,成为有机合成领域的研究热点之一。因此,对丙二腈参与的反应在有机合成中的应用展开综述,具有一定的理论研究意义。     

环糊精在污染土壤修复中的研究进展

环糊精由于其具有特殊的分子空腔结构,可以增容及解吸吸附在土壤中的有机污染物,并对土壤表层的有机污染物具有一定的光解促进作用,通过对环糊精改性还能达到同时去除土壤中有机物和重金属污染物的效果。目前环糊精作为环境友好型材料已经广泛的应用于环境治理中,文章介绍了环糊精及其衍生物在污染土壤修复方面的应用。     

新型第二代超分子大环主体化合物环糊精衍生物的合成及应用

简要介绍了环糊精化学的产生、发展、结构特征、性能及应用。详细介绍了:①新型环糊精衍生物的合成自组装及应用;②新型环糊精衍生物的合成及在医药学领域的应用;③新型环糊精衍生物在有机合成中的应用。并对环糊精化学的发展进行了展望。     

分子印迹聚合物在催化反应中的研究进展

分子印迹技术是将某一特定的目标分子作为模板,运用"锁钥"理论,制备出对该目标分子具有特异选择性聚合物的技术。分子印迹技术应用在诸多领域,如色谱分离、固相萃取、仿生传感等。近年来,分子印迹技术在催化领域的研究取得了重要的进展,本文重点介绍了印迹分子用作催化剂在有机反应中的应用,并对分子印迹聚合物在有机合成的发展方向上进行了展望。     

丙烯腈生产用催化剂研究进展

丙烯腈是重要的化工基本原料,丙烷氨氧化制丙烯腈反应工艺是潜在的具有较大经济效益的丙烯腈生产路线。本文介绍了丙烯腈的国内外生产情况,叙述了生产丙烯腈用催化剂的制备、性能和应用前景。     

Lipase made active in hydrophobic media

Enzymes are distinguished from other catalysts by their high substrate specificity. This is a great asset when one wants to apply them for syntheses of various compounds. Their usage, however, generally is limited to hydrophilic reaction media, because they usually are not soluble and active in hydrophobic media. Recently, we have been able to make various enzymes soluble and active in highly hydrophobic organic solvents. The key to this success is the chemical modification of enzymes with an amphipathic synthetic polymer, polyethylene glycol. The activated polymers can be attached to enzymes in aqueous buffer solutions, and once enzymes are modified they become soluble and active in various organic solvents such as benzene, toluene and cholorinated hydrocarbons and exhibit high enzymic activities in these organic solvents. Modified hydrolytic enzymes catalyzed the reverse reaction of hydrolysis in organic solvents. The modified lipase catalyzed various ester synthesis reactions. Because the reactions were conducted in the pure solvent system, it also was possible to study the kinetics and the substrate specificity for ester synthesis reaction. It also catalyzed the polymerization of a hydroxy group containing carboxylic acid due to the bifunctional nature. The modified lipase catalyzed ester exchange between an ester and an alcohol, between an ester and a carboxylic acid and between two esters in organic solvents. When the two substrates for ester exchange were liquid, the reaction could take place without organic solvents. The modified lipase catalyzed an ester exchange reaction between trilaurin and triolein when dissolved in these substrates. Dilauroyl-monooleoylglycerol and monolauroyl-dioleoyl-glycerol were formed from these two substrates in the presence of the modified lipase. The modified enzyme was extremely thermostable in its substrates. In the ester synthesis and ester exchange reactions, a trace amount of water was necessary for expression of the enzymic activity. It is suggested that the amphipathic polymer molecules retained water in close proximity to the enzyme. Presented at the symposium “The Biology, Biochemistry and Technology of Lipase” at the 78th annual meeting of the American Oil Chemists’ Society held May 17–21, 1987, in New Orleans, Louisiana.     

Thermodynamics of the encapsulation by cyclodextrins

Molecular encapsulation on a molecular basis can be performed by cyclodextrins. The inclusion of organic molecules into the interior changes the properties of these molecules, which may be used for a broad variety of applications. The affinity of guest molecules for the cavities of various cyclodextrins depends on the stereochemistry and on the interaction forces of the molecules involved. Calculations of the thermodynamic parameters show that the reaction entropy is highly important for the inclusion reaction. Completely different reaction mechanisms are observed for various types of cyclodextrins as some of these reactions show enthalpy–entropy compensation. Others are supported by the reaction entropy or are even entropically controlled. Protonation and deprotonation reactions contribute significantly to the inclusion reaction, as first of all the solubility of the compounds in water is strongly influenced by the acidity of the solution, and, moreover, all tautomeric forms of the compounds show different affinities to various cyclodextrins. Copyright © 2006 Society of Chemical Industry     

亲水/疏水复合膜强化膜蒸馏深度处理工业废水的研究进展

工业废水中通常含有多种疏水性有机污染物及表面活性剂,传统疏水微孔膜用于膜蒸馏处理工业废水的过程中,这些污染物容易沉积在膜表面引发膜污染和膜润湿,导致膜蒸馏过程的低效甚至失败。亲水/疏水复合膜是一种表层亲水而底层疏水的非对称膜材料,可通过在膜表面形成水合层减缓污染物的吸附累积,同时保留疏水基底膜对污染物的高截留率,用于膜蒸馏过程可有效强化其处理复杂工业废水的效果。本文概述了构筑亲水/疏水复合膜的仿生学原理与表面润湿理论,介绍了复合膜常用的制备方法,重点分析了多种亲水材料改性制备的复合膜用于膜蒸馏深度处理工业废水的强化效果及强化机制,认为复合膜表面形成的亲水层可有效抑制工业废水中疏水性污染物与膜表面的疏水-疏水相互作用,减轻膜污染及膜润湿倾向,提高污染物截留效率,而氧化石墨烯等亲水物质可加速水分子通过,提升膜蒸馏产水通量。最后指出未来亲水/疏水复合膜的发展可以通过建立污染物在复合膜中的传递模型,进一步探究复合膜对工业废水处理过程的强化机制,通过优化调控复合膜结构,提升复合膜对工业废水中多种污染物的截留率和抗污染性能,实现膜蒸馏抗污染性、截留率和产水通量的同步提升,并通过开展中试研究验证复合膜用于工业废水深度处理的经济性和长期稳定性。     

DNA stability in ionic liquids and deep eutectic solvents

DNA molecules are known as the genetic information carriers. Recently, they have been explored as a new generation of biocatalysts or chiral scaffolds for metal catalysts. There is also growing interest in finding alternative solvents for DNA preservation and stabilization, including two unique types of solvents: ionic liquids (ILs) and deep eutectic solvents (DES). Therefore, it is important to understand how DNA molecules interact with these novel ionic solvent systems (i.e. ILs and DES). It is well known that inorganic divalent and monovalent ions preferentially bind with major and minor grooves of DNA structures. However, in the case of ILs and DES, organic cations may intrude into the DNA minor grooves; more importantly, electrostatic attraction between organic cations and the DNA phosphate backbone becomes a predominant interaction, accompanied by hydrophobic and polar interactions between ILs and DNA major and minor grooves. In addition, anions may form hydrogen bonds with cytosine, adenine and guanine bases. Despite these strong interactions, DNA molecules maintain a double helical structure in most ionic solvent systems, especially in aqueous IL solutions. The exciting advances of G‐quadruplex DNA structures in ILs and DES are also discussed. © 2014 Society of Chemical Industry     

Amphiphilic building blocks for self-assembly: from amphiphiles to supra-amphiphiles

The process of self-assembly spontaneously creates well-defined structures from various chemical building blocks. Self-assembly can include different levels of complexity: it can be as simple as the dimerization of two small building blocks driven by hydrogen bonding or as complicated as a cell membrane, a remarkable supramolecular architecture created by a bilayer of phospholipids embedded with functional proteins. The study of self-assembly in simple systems provides a fundamental understanding of the driving forces and cooperativity behind these processes. Once the rules are understood, these guidelines can facilitate the research of highly complex self-assembly processes. Among the various components for self-assembly, an amphiphilic molecule, which contains both hydrophilic and hydrophobic parts, forms one of the most powerful building blocks. When amphiphiles are dispersed in water, the hydrophilic component of the amphiphile preferentially interacts with the aqueous phase while the hydrophobic portion tends to reside in the air or in the nonpolar solvent. Therefore, the amphiphiles aggregate to form different molecular assemblies based on the repelling and coordinating forces between the hydrophilic and hydrophobic parts of the component molecules and the surrounding medium. In contrast to conventional amphiphiles, supra-amphiphiles are constructed on the basis of noncovalent interactions or dynamic covalent bonds. In supra-amphiphiles, the functional groups can be attached to the amphiphiles by noncovalent synthesis, greatly speeding their construction. The building blocks for supra-amphiphiles can be either small organic molecules or polymers. Advances in the development of supra-amphiphiles will not only enrich the family of conventional amphiphiles that are based on covalent bonds but will also provide a new kind of building block for the preparation of complex self-assemblies. When polymers are used to construct supra-amphiphiles, the resulting molecules are known as superamphiphiles. This Account will focus on the use of amphiphiles and supra-amphiphiles for self-assembly at different levels of complexity. We introduce strategies for the fabrication of robust assemblies through self-assembly of amphiphiles. We describe the supramolecular approach for the molecular design of amphiphiles through the enhancement of intermolecular interaction among the amphiphiles. In addition, we describe polymerization under mild conditions to stabilize the assemblies formed by self-assembly of amphiphiles. Finally, we highlight self-assembly methods driven by noncovalent interactions or dynamic covalent bonds for the fabrication of supra-amphiphiles with various topologies. Further self-assembly of supra-amphiphiles provides new building blocks for complex structures, and the dynamic nature of the supra-amphiphiles endows the assemblies with stimuli-responsive functions.     

Environmentally friendly photosensitizer: starch modified with chlorophyll‐type chromophores

A novel water‐soluble polymeric photosensitizer (SPheo) based on starch and containing pheophorbide (Pheo), a chlorophyll‐derived chromophore, was synthesized and its photophysical and photochemical properties were studied. Pheo chromophores attached to the polymeric chains of starch absorb light of the UV‐visible spectral region. The clustering of hydrophobic Pheo chromophores results in the formation of hydrophobic microdomains in aqueous solution where organic molecules can be solubilized. SPheo polymer efficiently photosensitizes reactions mediated by energy and/or electron transfer from the electronically excited chromophores to the molecules of organic compounds solubilized in polymeric microdomains or residing in water. Copyright © 2007 Society of Chemical Industry     

Protein-reactive,molded polystyrene surfaces having applications to immunoassay formats

Injection-molded polystyrene surfaces were chemically modified rendering them protein reactive. The process involves chlorosulfonation of the aromatic ring, sulfonamide formation with excess di- and triamines, and reaction of the residual pendant amines with various bifunctional molecules. Surfaces possessing pendant bromoacetyl, iodoacetyl, fluorodinitrophenyl, and trimellitic anhydride were prepared and can exhibit up to ten times more protein immobilization capability compared to unfunctionalized polystyrene, where the coupling takes place presumably via hydrophobic interaction.     

THE VAPOR-LIQUID EQUILIBRIUM OF ETHANOL-WATER MIXTURE IN THE PRESENCE OF BENZYLTRIETHYLAMMONIUM CHLORIDE SALT AT ATMOSPHERIC PRESSURE

The phase transfer catalysis reaction is gaining more and more attention in chemical industry. Usually, the chemicals used as phase transfer catalyst are organic salts. Unfortunately, the effect of an organic salt on the vapor-liquid equilibrium (VLE) of a mixture has hardly been reported in literature. In this study, the effect of the benzyltriethylammonium chloride organic salt on the VLE of ethanol-water mixture was obtained experimentally. It is observed that this organic salt can shift and even break away the azeotrope of ethanol -water mixture as an inorganic salt does. The experimental data were correlated with the models or Tan (1987, 1990) and Ohe (1991). The results were not satisfactory probably due to the complicated interactions among ions and molecules and the big different particle sizes or ion, solvent molecule, and salt molecule.

The vapor pressures of benzyltriethylammonium chloride-ethanol mixtures needed in this study for determining solvent-salt interaction parameters in the correlation model were also measured and regressed by the Patil model (1990).     

Removal of trace VOCs from water through PDMS membranes and analysis of their permeation behaviors

The removal of trace chlorinated hydrocarbons from water has been performed through poly(dimethylsiloxane), which had been fabricated by addition crosslinking reaction. The membrane had a more hydrophobic characteristic than that fabricated by a condensation reaction because it has no polar groups in the polymeric chain, such as hydroxyl and chlorine groups. This study concentrated on the comparison of the permeation behaviors of homologous series of chloromethanes aqueous solutions with that of a chloroethane solution. It was suggested that when the hydrophobic characteristics of a membrane system is greater, water molecules in the membrane tend to exist in the form of clusters; thereby, the permeating size of water component increases, resulting in suppressing water permeation and increasing the enrichment factor for the organic component. The permeation behaviors at various temperatures and membrane thicknesses were indirectly interpreted in terms of the effect of concentration polarization and the effect of interactions of organic–membrane, and water–organic-absorbing membrane. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 601–611, 1999