壳聚糖及其衍生物抗菌机理研究进展

壳聚糖及其衍生物的抗菌活性和优良加工性能,使其成为具有巨大潜力的抗菌材料,可用于食品保鲜、伤口敷料和组织工程等方面。本文综述了近年来在壳聚糖基材料抗菌模型、影响抗菌活性因素及抗菌活性优化方案方面的研究进展,希望对壳聚糖衍生物抗菌材料的制备及优化提供参考。     

壳聚糖及其衍生物处理工业废水的研究进展

综述了近年来壳聚糖及其衍生物在处理工业废水中的应用.壳聚糖及其衍生物可处理工业废水中的重金属离子,如Cr（Ⅵ）、Cu（Ⅱ）和Zn（Ⅱ）等;可处理含染料的工业废水,如处理直接紫B、直接绿BE以及甲基橙等染料;还可用于处理印染、造纸和含油废水.壳聚糖及其衍生物具有易分离、可生物降解,无污染等特点,是绿色的水处理剂,且我国壳聚糖资源极为丰富,探索其在工业废水处理中的应用有着重要的价值.     

可见光诱导α-氨基酸衍生物脱羧偶联反应研究进展

氨基酸是一类来源丰富、廉价易得并且绿色环保的生物质原料,可用于合成高附加值生物活性分子、药物和功能材料等,还可作为有机催化剂或金属配体用于不对称合成转化.可见光是绿色清洁的可再生资源,具有丰富易得、环境友好和应用潜力巨大等优点,其催化的反应条件温和且化学选择性好.利用可见光催化α-氨基酸衍生物脱羧偶联构建种类丰富的含氮化合物是一种极具吸引人的合成策略.综述了近年来光催化α-氨基酸衍生物脱羧偶联反应的研究进展.     

1,8-萘啶衍生物的结构、光物理性质及其应用

1,8-萘啶衍生物的刚性平面氮杂环结构使其具有丰富的光物理性质,因而在金属离子识别、配位化学等方面有着广泛的应用. 许多1,8-萘啶衍生物还具有独特的生理活性,并应用于临床治疗,这为该类化合物在生物医学领域中的研究和应用奠定了基础. 本文简要介绍了1,8-萘啶衍生物的结构特点及近期的研究进展.     

水溶性金属勒烯衍生物的合成和表征

金属富勒烯具有表面积大(2 nm2)、整体电中性、金属离子的解离常数Kd为0等独特的性质, 在医学上具有重要的应用价值[1～7]. 要将其用于生物体系, 需引入亲水基团. 水溶性Gd@C82(OH)x已被证实是一种比临床上应用的GdDTPA更好的核磁成像造影剂(其弛豫率比GdDTPA高20倍[7]), 并有望用作放射性示踪剂和放射性药物等, 且在生物体内外具有稳定性[2～6], 是生物医学上很有吸引力的材料. 本文在高效合成、分离纯化 Gd@C82的基础上合成了其多羟基衍生物、多取代氨基酸衍生物和多取代氨基磺酸衍生物, 并作了初步分析.     

二苯胺取代吖啶衍生物发光材料的合成、表征及电致发光性能

设计合成了2个苯胺取代吖啶衍生物N3,N3,N6,N6-四苯基吖啶基-3,6-二胺(1)和N3,N3,N6,N6-四对甲苯基吖啶基-3,6-二胺(2),通过化学修饰在吖啶核的两端引入二苯胺取代基可以调节化合物的能级和堆积结构等性质,从而使这些吖啶衍生物具有良好的发光性能,可用于制备电致发光器件.基于吖啶衍生物为掺杂发光材料制备的电致发光器件均呈现绿光发射,器件开启电压较低(2.4 V),以化合物1和2制备的器件最高功率效率分别为4.9和8.2 lm/W.考察了其光物理、电化学、热学和荧光量子效率等性能.结果表明,化合物1和2具有较高的量子效率及匹配的能级结构,这是获得较高电致发光效率的基础.     

一种光致相变型偶氮苯基柔性光热转换器件的制备及性能

设计合成了一种具有室温光致固液转换性能的偶氮苯衍生物1-[4-(烯丙氧基)苯基]-2-(对甲苯基)二氮烯(AD-Azo)用于制备太阳热能燃料(STFs),结合其固液转换过程中的相变潜热,较大幅度提高了偶氮苯衍生物的能量存储密度.在光/热诱导下使其与普通商用布料结合,制备了环境友好、即用式柔性太阳热能燃料器件AD-Azo STF.利用织物内分子间超分子作用(氢键),增强了能量存储密度和储能寿命,使其总储能密度高达199.12 J/g,储能半衰期为50 h.该柔性AD-Azo STF器件具有良好的柔韧性、溶剂稳定性和循环使用性,在环境友好型太阳热能燃料中具有良好的应用前景.     

呋喃衍生物:一类新兴的有机半导体材料

π-共轭分子广泛用于有机场效应晶体管、有机太阳能电池、染料敏化太阳能电池和有机发光二极管等领域中.在π-共轭分子中引入呋喃环可以显著的改变分子的光学、电化学、电荷传输等性质.π-共轭呋喃衍生物由于具有载流子迁移率高、荧光量子效率高以及溶解性好等特点,引起了国内外广泛的研究兴趣.实验和理论研究都已证明呋喃衍生物是一类优良的半导体材料,可以用于制得高性能的场效应晶体管、有机太阳能电池、染料敏化太阳能电池和有机发光二极管.作者在简单介绍呋喃衍生物特点的基础上,着重介绍了呋喃衍生物应用于制备有机场效应晶体管、有机太阳能电池、染料敏化太阳能电池和有机发光二极管等领域中的研究进展.     

一种新型疏水改性的两亲性壳聚糖衍生物的表面活性研究

鉴于甲壳质的生物降解性、生物活性和生物相容性等诸多特性 ,其开发利用正受到人们的广泛重视[1] .具有不同性能和功效的衍生物已在医药、食品、日用化工、纺织、水处理等领域发挥了重要的作用 [2～ 4 ] .然而具有表面活性的两亲性衍生物却少见报道 [5,6] .本文将羧甲基壳聚糖进行疏水改性 ,使其分子上同时具有亲水基和疏水基 ,从而具有两亲性质 ,可以降低溶液的表面张力 ,并在溶液中形成胶束 .可望在日用化工、医药、食品等领域起到降低表面张力、增稠、乳化和增溶等作用 .1　实验部分1 .1　原料及仪器　羧甲基壳聚糖 (CMCHS,青岛生化制…     

1,5-苯并硫氮杂卓-α-恶唑烷酮-β-内酰胺衍生物的光谱研究(Ⅱ)

苯并硫氮杂卓-β-内酰胺化合物是目前广泛用于临床的广谱抗生素药物.它的抗生素生理活性与其结构有着密切联系,为使该类化合物更具生理活性和优良药效,合成了五种新的1,5-苯并硫氮杂卓-α-恶唑烷酮-β-内酰胺衍生物,并用核磁共振(NMR)、质谱(MS)、红外光谱(1R)及元素分析确定了其衍生物结构,分析和讨论了该类衍生物的光谱特征及其规律,确定了该类衍生物结构的分析判据.     

新戊二醇-三羟甲基甲胺二元体系相图

多元醇是一类具有技术和经济潜力的相变贮热材料［１ -３］．对多元醇及其二元体系贮热性能的研究已日趋完善,而对于其相图的研究则较少．本文采用以下三种实验技术测绘了ＮＰＧ ＴＡＭ二元体系相图：（１）热分析,以得到组成与相转变温度的关系;（２）变温红外光谱的研究,通过特征吸收峰随温度的变化,可以得到相转变温度区间,辅助相图的绘制;（３）Ｘ射线衍射,通过淬冷的方法来获得高温下的物相,测其Ｘ衍射图,进行相区分析．１实验１．１试剂ＮＰＧ：为超纯试剂,日本东京化成株式工业会社生产：ＴＡＭ：分析纯,北京化学试剂厂…     

气相色谱法测定碳酸二甲酯的含量

选用HP-INNOWAX毛细管色谱柱及氢火焰离子化检测器(FID)，采用二阶程序升温，以正丁醇为内标物，建立了测定碳酸二甲酯(DMC)含量的气相色谱法。当DMC的体积分数(X)为0．02％～0．64％时，DMC与正丁醇的峰面积比(Y)与DMC的体积分数(X)有良好的线性关系，线性回归方程为Y=0．4427X-0．0406，相关系数r=0．9994．检出限为0．1nL。对实际样品进行测定，加标回收率为93．7％～97．0％，相对标准偏差为0．84％～1．27％。方法适用于DMC的含量分析。     

新型单组分磷氮膨胀阻燃剂的合成

以新戊二醇与三氯氧磷为原料,合成了5,5-二甲基-1,3-二氧杂己内磷酰氯;进而将5,5-二甲基-1,3-二氧杂己内磷酰氯分别与苯并咪唑类衍生物反应,得到三种新型单组分磷氮膨胀阻燃剂(Ⅲa-c).利用IR1、HNMR、质谱及元素分析等表征了Ⅲa-c三种化合物的结构;并利用热重分析考察了三种化合物的热稳定性能.结果表明,目标产物Ⅲa-c均有较好的成炭性和热稳定性,600℃时残炭质量分数分别达26.93%、23.62%及18.75%.     

Water swelling of polyester networks

The water equilibrium concentration in styrene crosslinked polyesters increases with the temperature; this behaviour has been interpreted in terms of material expansion induced by temperature. We have verified this hypothesis by swelling measurements in water and gravimetric experiments at various temperatures between 30°C and 90°C. Samples were propylene glycol/neopentyl glycol - maleate / isophthalate copolymers crosslinked by styrene.     

Photo-degradation of poly(neopentyl isophthalate). Part II: Mechanism of cross-linking

The mechanism of cross-linking of poly(neopentyl isophthalate) (PNI) by photo-degradation in nitrogen atmosphere was investigated. The exposure of PNI to UV light resulted in gel (insoluble material) formation. The gel material was collected and the morphology of the gel material was characterized with SEM. The gel has the highest density near the coating surface. To obtain information on the cross-linking at a molecular level the gel was decomposed by methanolysis and the decomposition products were analysed with LC-MS. Besides the expected “grafting” types of cross-links (phenyl-to-phenyl coupling) also “chain coupling” types of cross-links were detected (recombination of neopentyl glycol based moieties). Analysis of samples that had been exposed to UV light in air indicates that the phenyl-to-phenyl coupling also occurs in the presence of oxygen.     

Synthesis of polyesters as binders for deinkable inks. I. Structural analysis of the polyesterification between o-phthalic anhydride and neopentyl glycol in bulk at 200°C by high resolution 13C nuclear magnetic resonance (13C-NMR)

Analysis of the polyesterification in bulk without any external catalyst at 200°C of o-phthalic anhydride with neopentyl glycol (2,2-dimethyl-1,3-propanediol) with a mole ratio ([(SINGLE BOND) COOH]/[ (SINGLE BOND) OH]) = 0.7 has been carried out by high resolution ¹³C nuclear magnetic resonance (¹³C-NMR). Polyesters can be analyzed by ¹³C-NMR spectra because of the fact that both o-phthalic acid (o-phthalic anhydride) and neopentyl glycol carbons are sensitive to sequence effects. Spin-lattice relaxation times T₁, of quaternary, tertiary and secondary carbons in different structures are in the 0.1–6.5 s range depending on the neighboring residue effects in the polymer chain. © 1996 John Wiley & Sons, Inc.     

Determination of Anti-icing Additives in Jet Fuels

Abstract

A specific method to determine two anti-icing additives (ethylene glycol monomethylether, EGME and diethylene glycol monomethylether, DEGME) in jetfuel is described. This method is based on a gas-chromatographic technique using a mass spectrometer detector and the monitoring of selected ions (GC-MS-SIM). This specific technique has shown to be an accurate and rapid tool to carry-out these measurements in such a complex hydrocarbon matrix. The GC-MS-SIM technique, because of its specificity, does not require sample pre-treatments other than trichloroethylene (TCE) which has been selected as an internal standard. The analysis of both EGME and DEGME can be performed in less than 10 minutes in a sample of 1–5 mL. Several fuel samples were analyzed and the results compared with two standard methods.     

Miscibility of some poly(neopentyl glycol adipate)/chlorinated polymer blends

Poly(neopentyl glycol adipate), PDPA, was found to be miscible with poly(epichlorohydrin-co-ethylene oxide). PDPA also formed miscible blends with chlorinated polyethylene samples containing 48 and 42% by weight of chlorine. Chlorinated polyethylene with a lower chlorine content was not miscible with PDPA.     

Thermal Processes in Aluminum Blends with Some Alcohols after High-Pressure Plastic Deformation

Binary blends of powdered aluminum with polyhydric alcohols (pentaerythritol, trimethylolpropane, neopentyl glycol, and poly(vinyl alcohol)) have been subjected to plastic deformation under pressures of 0.5–2.0 GPa. Differential scanning calorimetry has shown that exothermic processes occur in the blends due to the interaction of the organic phase with aluminum atoms on a freshly formed surface of aluminum particles.     

Fine‐Tuning the Nucleophilic Reactivities of Boron Ate Complexes Derived from Aryl and Heteroaryl Boronic Esters

Boron ate complexes derived from thienyl and furyl boronic esters and aryllithium compounds have been isolated and characterized by X‐ray crystallography. Products and mechanisms of their reactions with carbenium and iminium ions have been analyzed. Kinetics of these reactions were monitored by UV/Vis spectroscopy, and the influence of the aryl substituents, the diol ligands (pinacol, ethylene glycol, neopentyl glycol, catechol), and the counterions on the nucleophilic reactivity of the boron ate complexes were examined. A Hammett correlation confirmed the polar nature of their reactions with benzhydrylium ions, and the correlation lg k(20 °C)=s_N(E+N) was employed to determine the nucleophilicities of the boron ate complexes and to compare them with those of other borates and boronates. The neopentyl and ethylene glycol derivatives were found to be 10⁴ times more reactive than the pinacol and catechol derivatives.