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…     

一种用于电热蒸发-原子光谱的微型化固相萃取技术

与传统的液 液萃取相比 ,固 液萃取技术具有省时、溶剂用量少、不易乳化和高富集因子等优点[1],它可与各种检测方法联用[2 ],已在痕量无机物或有机物的分离富集与测定中广泛应用 .但是常规的固相萃取中的洗脱过程存在洗脱体积大 ,时间长及要求二次处理等缺点 ,这与电热蒸发 (ＥＴＶ)进样 /电感耦合等离子体原子发射光谱 /质谱 (ＩＣＰ ＡＥＳ/ＭＳ)和电热原子吸收光谱 (ＥＴＡＡＳ)很不匹配 .基于此 ,本文设计了一种填充有Ｐ5 0 7萃淋树脂 ( 1 40目 )的超微柱 ( 0 6μｍ(ｉ.ｄ .)× 1 0ｍｍ) .它既可用作分离富集柱 ,又可作为ＥＴＶ ＩＣＰ…     

固相微萃取与色谱联用方法分析水中12种有机氯化合物

运用顶空固相微萃取与色谱闻用方法（ＨＳ－ＳＰＭＥ－ＧＣ）对水中的残留有机氯化合物进行了分析。对影响ＨＳ－ＳＰＭＥ－ＧＣ分析灵敏度的各种实验因素如涂层种类,萃取温度、平衡时间,离子浓度等进行了讨论并将该方法与固相萃取法（ＳＰＥ）,液液萃取法（ＬＬＥ）作了对比,同时考察了常见环境共存污染物直链烷基苯磺酸钠（ＬＡＳ）对几种方法的影响。     

氟氢化钾固-固相变的变温红外光谱测定

氟氢化钾（KHF2）晶体随着温度的升高,在196℃发生可逆的固－固相变,晶型由低对称的西方晶系转变到高对称的立方晶系^[1]。由于氟氢化钾的固－固相变焓高,可应用于热能的贮存^[2],它的高温相可用做高电导率的离子导体^[3]。氟氢化钾的应用强烈依赖于本身的晶体性,因此利用各种光谱、X－射线衍射、热分析等技术手段以及量子化学计算对两种晶相结构的研究已日趋完善^[4,5]。而对于其固－固相变升温过程中的动态测定还未见报道,这是由于一般的实验手段难以对升温过程进行原位跟踪所致。变温红外光变法具有简便、快速、实用等优点,因而成为研究相变的有力工具^[6]。本文采用变温红外光谱技术测定了氟氢化钾在不同温度下的红外光谱,发现当温度升高到固－固相变温度时,氟氢化钾的各个特征吸收峰的位置、强度及峰形均发生较大程度的变化,从而为验证氟氢化钾的固－固相变机理提供了依据。     

固载杂多酸催化合成2,4-二甲基-2-(4-甲基-3-戊烯基)-1,3-二氧五环

环缩酮类香料化合物[1 3]是在催化剂存在下由相应的酮和多元醇经缩合反应而制得。已报道的催化剂有质子酸[1]、固体酸[2,3]和某些金属盐类[4～7]等。本文以大孔阳离子交换树脂固载磷钨酸催化6 甲基 5 庚烯 2 酮与1,2 丙二醇的缩合反应,催化剂活性高,且可重复使用,后处理简便。1　实验1 1　仪器和试剂ＷＹＡ 1Ｓ阿贝折光仪;ＰＥ 2400ＣＨＮ元素分析仪;ＰＥ 783红外光谱仪。6 甲基 5 庚烯 2 酮、1,2 丙二醇、钨酸钠、磷酸氢二钠、盐酸等均为分析纯;大孔阳离子交换树脂(Ｄ001 ＣＣ型)。1 2　制备1 2 1　催化剂　以二水钨酸钠和十二水磷酸氢…     

固相微萃取中高分子涂层的研究

 聚甲基乙烯基硅氧烷首次被用作固相微萃取（ＳＰＭＥ）装置的固相涂层,通过顶空固相微萃取气相色谱分析（ＨＳ－ＳＰＭＥ－ＧＣ）对使用聚甲基乙烯基硅氧烷固相涂层的ＳＰＭＥ装置进行了评价。对其使用厚度、温度及选择性进行了较深入的研究,找到了它的最佳使用条件和适用范围,并与商品化的ＳＰＭＥ涂层作了比较。对ＨＳ－ＳＰＭＥ－ＧＣ和ＨＳ－ＧＣ两种方法也作了比较,指出两者的适用范围不同。     

固—液相转移催化合成—氯苯氧乙酸

用固－液相转移催化法合成了对－氯苯氧乙酸，研究了不同料比，催化剂，反应温度对产率的影响，用ＰＥＧ８００和ＫＩ双组分催化剂，制得对－氯苯氧乙酸，产率９４．８％。     

可溶性聚合物无痕连接合成N-(p-羟基-苯甲酰基)-N'-芳基脲化合物

取代脲化合物由于其非凡的生物活性和广泛的应用前景 ,研究十分活跃[1 ] 。目前 ,多采用经典液相法和固相合成法[2～ 6] 。近年来可溶性聚合物在有机合成中得到快速发展 ,大量用于药物的组合合成和生物活性的筛选[7] ,我们曾以ＰＥＧ为载体 ,采用不同的连接策略 ,支载合成了硫脲化合物[8,9] 。本文探讨以ＰＥＧ作载体 ,草酰氯作连接基 ,无痕连接组合合成Ｎ (ｐ 羟基 苯甲酰基 ) Ｎ′ 芳基脲化合物。合成路线如下 :　　ＷＲＳ 1Ａ型数字熔点仪 (温度计未校正 ) ;ＰＥ2 4 0 0ＣＨＮ元素分析仪 ;ＰＥ(Ｏｎｅ)型红外光谱仪 (ＫＢｒ压片 ) ;Ｂｒ…     

变温红外确定硫氰化铵固-固相变机理(英文)

硫氰化铵分子晶体在固 固转变时 ,能可逆地吸收大量的热。作者利用变温红外光谱确定了其固 固相变机理。结果表明 ,随着温度升高 ,固 固转变时分子晶体内相邻的氢键断裂 ,晶型由低对称转变为高对称并引入振动和转动无序 ,吸收大量热。     

固/液界面现场光谱电化学

固/液界面现场光谱电化学的方法包括各种电磁波透射和反射谱(紫外可见、拉曼、红外、X-光等)、磁共振谱(ESR、NMR)以及80年代发展起来的扫描显微谱(STM等)和非线性反射光谱(SHG)等等。固/液界面现场光谱电化学已渗透到固/液界面和电极表面结构,分子水平上的吸脱附和反应机理,电催化和反应动力学等许多研究领域。本文结合文献对上述几个方面以及固/液界面现场光谱电化学的发展方向进行综述。     

Electronic absorption spectroscopy probed side-chain movement in chromic transitions of polydiacetylene vesicles

Thermochromism, solvatochromism, and alkalinochromism of a poly-10,12-pentacosadiynoic acid (poly(PCDA)) vesicle solution are studied by electronic absorption spectroscopy. The spectroscopic profiles reveal different sequences of side-chain movement during the chromic transitions. The gradual hypsochromic shift and reversibility of the purple solution at low temperature in the thermochromic transition indicates that the transition starts with reversible conformational alteration of methylene side chains leading to metastable purple vesicles. Further heating to 80 degrees C or higher eventually causes the hydrogen bonds at the carboxylic head groups to break and turns the vesicle solution to red. The irreversibility of the red vesicles indicates that it is the most thermodynamically stable form. In the ethanolochromism and alkalinochromism, the processes are however induced at the vesicle-media interface, directly bringing about the hydrogen bond breaking. The purple solutions observed in the ethanolochromism and alkalinochromism cannot reverse back to the blue one. The absorption spectra clearly demonstrate that they are mixtures of the blue and red vesicles.     

月桂胺盐酸晶体相变的红外光谱研究

在290-365K的温度区间内考察了月桂胺盐酸盐晶体红外光谱随温度的变化规律。结果表明:月桂胺盐酸盐在339K发生了固-固结构相变, 该相变的预相变起始点为327K。在327K以下的低温相中, 晶体中分子的碳氢链以高度有序的全反式构象存在, 极性头部的三个N-H-Cl氢键是不等价的。在327-339K的中间过渡相, 碳氢链中出现了旁式构象, 分子链间相互作用减弱。不等价的N-H-Cl氢键的差异减小。在339K以上的高温相中, 分子旁式链构象的增多导致了分子链横向堆积无序性的明显增加, 三个N-H-Cl氢键已变得等价。     

Hydrogen Bonding of Carboxylic Acids in Aqueous Solutions—UV Spectroscopy, Viscosity, and Molecular Simulation of Acetic Acid

The UV spectra of aqueous acetic acid solutions up to 2M were investigated. At these wavelengths, the carboxylic acids exhibit an absorption peak, attributed to the C=O group, which shifts when hydrogen bonds are formed.. The measured spectra were best fitted to several bands, either of Gaussian or Lorentzian shape, which can be explained as several types of structural units formed by hydrogen bonds established between acetic acid and water molecules and between acetic acid molecules themselves. Molecular dynamics simulation of these mixtures was also performed, confirming the occurrence of several types of hydrogen bonds and showing the presence of dimers at higher concentrations. The viscosity and density of these solutions were also measured at different concentrations and temperatures. These results give a more complete picture of the hydrogen bond network of the system.     

Raman spectroscopic and DSC studies of diglycine-perchlorate (DGPCl)

Single crystals of diglycine perchlorate (DGPCl) and deuterated diglycine perchlorate (DDGPCl) are synthesized and studied using differential scanning calorimetry (DSC) and Raman spectroscopy. DSC data indicated that both DGPCl and DDGPCl undergo a reversible first-order phase transition (solid-solid) at −11.5 °C and −9.3 °C, respectively. The Raman spectra of DGPCl and DDGPCl obtained at ambient temperature are analyzed to infer on the strength of hydrogen bonding in this compound relative to the parent compounds. The occurrence of NH stretching frequency at higher value in DGPCl in comparison with glycine suggests presence of a weak N–H?O hydrogen bond in DGPCl than in glycine. The lower isotropic melting temperature of DGPCl as compared to that of glycine is understood on the basis of the relative strength of hydrogen bonding in these compounds.     

Physicochemical properties and solubility of alkyl-(2-hydroxyethyl)-dimethylammonium bromide

Quaternary ammonium salts, which are precursors of ionic liquids, have been prepared from N,N-dimethylethanolamine as a substrate. The paper includes specific basic characterization of synthesized compounds via the following procedures: nuclear magnetic resonance (NMR) and Fourier transform infrared (FTIR) spectra, water content, mass spectroscopy (MS) spectra, temperatures of decompositions, basic thermodynamic properties of pure ionic liquids (the melting point, enthalpy of fusion, enthalpy of solid-solid phase transition, glass transition), and the difference in the solute heat capacity between the liquid and solid at the melting temperature determined by differential scanning calorimetry (DSC). The (solid + liquid) phase equilibria of binary mixtures containing (quaternary ammonium salt + water, or + 1-octanol) has been measured by a dynamic method over wide range of temperatures, from 230 K to 560 K. These data were correlated by means of the UNIQUAC ASM and modified nonrandom two-liquid NRTL1 equations utilizing parameters derived from the (solid + liquid) equilibrium. The partition coefficient of ionic liquid in the 1-octanol/water binary system has been calculated from the solubility results. Experimental partition coefficients (log P) were negative at three temperatures.     

用红外光谱研究具有互穿网络结构的pH/温度双重敏感性微凝胶的相转变行为

采用傅立叶变换红外光谱仪测试了由聚(N-异丙基丙烯酰胺)(PNIPA)和聚丙烯酸(PAA)两种聚合物网络形成的具有互穿聚合物网络结构(IPN)的pH/温度双重敏感性微凝胶D2O分散液,通过差谱技术对不同pH值和温度条件下的红外吸收光谱进行处理,研究微凝胶相转变过程中分子链微环境的变化.结果表明,随着D2O介质的pH值增...     

Structural transition in alcohol-water binary mixtures: A spectroscopic study

The strengthening of the hydrogen bonding (H-bond) network as well as transition from the tetrahedral-like water network to the zigzag chain structure of alcohol upon increasing the alcohol concentration in ethanol-water and tertiary butanol (TBA) — water mixtures have been studied by using both steady state and time resolved spectroscopy. Absorption and emission characteristics of coumarin 153 (C153), a widely used non-reactive solvation probe, have been monitored to investigate the structural transition in these binary mixtures. The effects of the hydrogen bond (H-bond) network with alcohol concentration are revealed by a minimum in the peak frequency of the absorption spectrum of C153 which occur at alcohol mole fraction ∼0·10 for water-ethanol and at ∼0·04 for water-TBA mixtures. These are the mole fractions around which several thermodynamic properties of these mixtures show anomalous change due to the enhancement of H-bonding network. While the strengthening of H-bond network is revealed by the absorption spectra, the emission characteristics show the typical non-ideal alcohol mole fraction dependence at all concentrations. The time resolved anisotropy decay of C153 has been found to be bi-exponential at all alcohol mole fractions. The sharp change in slopes of average rotational correlation time with alcohol mole fraction indicates the structural transition in the environment around the rotating solute. The changes in slopes occur at mole fraction ∼0·10 for TBA-water and at ∼0·2 for ethanol-water mixtures, which are believed to reflect alcohol mole fraction induced structural changes in these alcohol-water binary mixtures.     

Untersuchungen über das Verhalten organischer Mischphasen 9. Mitteilung Vergleich der binären Systeme Tetrahydrofuran mit Wasser,Methanol und Cyclohexan,Diäthyläther mit Wasser,Methanol und Cyclohexan und Tetrahydrofuran-Diäthyläther

Activities and mixing functions of the following binary systems at 25° C are discussed: 1. mixtures of tetrahydrofuran with water, methanol, and cyclohexane; 2. mixtures of diethyl ether with water, methanol, and cyclohexane, and 3. mixtures of tetrahydrofuran with diethyl ether. Comparison with similar systems shows that in systems containing methanol, the strongest interactions are formation and breaking of hydrogen bonds between alcohol molecules; interactions between methanol and ether molecules play a minor rǒle. Systems containing water exhibit two main kinds of interaction: formation and breaking of hydrogen bonds between water molecules, and formation of hydrogen bonds between water and ether molecules. Deviations from ideality are larger for diethyl ether than for tetrahydrofuran in water and methanol, and smaller in cyclohexane.     

Charge resonance character in the charge transfer state of bianthryls: effect of symmetry breaking on time-resolved near-IR absorption spectra

We study the effects of symmetry breaking on the photogenerated intramolecular charge transfer (CT) state of 9,9'-bianthryl (BA) with femtosecond time-resolved near-IR spectroscopy. The time-resolved near-IR spectra are measured in acetonitrile for a symmetric substituted derivative of 10,10'-dicyano-9,9'-bianthryl (DCBA) and asymmetric substituted derivatives of 10-cyano-9,9'-bianthryl (CBA) and 9-(N-carbazolyl)anthracene (C9A), as well as nonsubstituted BA. The transient near-IR absorption spectrum of each compound at 0 ps has a locally excited (LE) absorption band, which agrees with the transient absorption band of the corresponding monomer unit. At 3 ps after the photoexcitation, the symmetric compounds show a broad charge transfer (CT) absorption band, whereas no absorption peak appears in the spectra of the asymmetric compounds. The broad CT absorption at 1250 nm only observed for the symmetric compounds can be attributed to the charge resonance transition associated with two equivalent charge separated states.