聚醚砜-羟基磷灰石混合溶液的流变性能

采用N,N-二甲基乙酰胺（DMAc）为溶剂配制含羟基磷灰石（HAP）的聚醚砜（PES）溶液,研究了PES-HAP-DMAc体系的流变曲线以及HAP的质量分数、混合溶液温度等对流变性能的影响。结果表明：混合溶液的非牛顿指数（n）随着温度的升高、HAP质量分数的增大而降低,表现为非牛顿流体。     

低浓度HPAM/AlCit交联聚合物溶液性质研究

采用粘度法、扫描电镜（SEM）、核孔膜过滤、动态光散射（DLS）和27Al NMR法，研究了高分子量低浓度的部分水解聚丙烯酰胺（HPAM）与柠檬酸铝（AlCit）体系交联反应过程溶液性质变化.结果表明，HPAM与AlCit反应在低剪切速率时体系粘度随反应进行而降低，在剪切速率较高时具有剪切稠化现象，HPAM与AlCit反应过程中交联态Al的自旋 晶格弛豫时间随反应进行变短.低浓度的HPAM与AlCit发生分子内交联反应形成交联聚合物线团（LPC）在水中的分散体系，即交联聚合物溶液（LPS）.交联聚合物溶液中LPC的平均流体力学半径约为238 nm，其形态接近球形，具有多分散性. LPS对1.2 μm核孔膜的封堵程度与其反应时间有关.     

甘氨酸的杂多酸超分子化合物的合成及性质研究

首次合成了甘氨酸的Keggin结构杂多酸超分子化合物(HGly)3[PW12O40]·5H2O(HGly)4[SiW12O40]·4H2O,用元素分析,IR,UV,TG-DTA,XRD和NMR等方法对标题化合物进行了表征,并讨论了它们的合成条件及结构特性.     

298.15和308.15 K温度条件下甘氨酰甘氨酸在电解质溶液中的热力学性质的研究:体积性质

利用精密数字密度计测定了298.15和308.15 K甘氨酰甘氨酸在KCl-水和NaCl-水混合溶剂中的密度, 计算了甘氨酰甘氨酸的表观摩尔体积V_Φ和极限偏摩尔体积V_Φ^?, 得到了其由纯水溶剂转移至混合溶剂中的迁移偏摩尔体积Δ_trsV_Φ^?和理论水化数N_h. 正的迁移偏摩尔体积说明在本文所研究的浓度范围内盐溶液可以提高球形蛋白的结构稳定性. 结果表明, 温度对迁移偏摩尔体积的影响很小; 溶液中离子与甘氨酰甘氨酸带电中心间的相互作用占主导地位. 利用共球交盖模型对结果进行了讨论.     

2,4-二羟基苯甲醛缩甘氨酸的合成及荧光法测定粮食中痕量锌

合成了新席夫碱试剂2,4 二羟基苯甲醛缩甘氨酸(DHBZGC),并测定了其结构,基于Zn(Ⅱ)与DHBZGC OP形成配合物,导致体系荧光增敏的特性,提出了一种测定痕量锌的荧光方法。在pH6.5～8.0,NaH2PO4 Na2HPO4缓冲溶液和OP存在时,Zn(Ⅱ)与DHBZGC形成1∶1的配合物。在λex为330nm,λem为445nm处产生的荧光增敏最大,Zn(Ⅱ)在0～100μg·L-1范围内符合线性关系,检出限为0.4μg·L-1。方法应用于粮食中痕量锌的测定,结果满意。     

17α-羟基黄体酮乙酸酯含量测定方法研究

17α 羟基黄体酮乙酸酯 (17α Hydroxyproges teroneacetate) ,俗名单酯 ,化学名 17 α 乙酰氧基 孕甾 4 烯 3,2 0 二酮 ,分子结构式为 :制药工业上主要用作安宫黄体酮、甲地孕酮等原药的中间体。其含量是生产中产品质量监控的一项重要指标。我国药典规定了甲地孕酮的测定方法[1] ,文献 [2 ]介绍了HPLC法分析甾体激素的进展 ,有关 17α 羟基黄体酮乙酸酯的文献很少。本文研究了反相液相色谱法 (RP HPLC)直接测定原料药中 17α 羟基黄体酮乙酸酯含量的方法 ,本法简单、准确、快速 ,适用于产品质量监控及分析。1　试验部分1.1　仪器…     

硝基甲苯异构体的液晶溶液热力学性质的色谱法研究

本文用气液色谱方法研究了o-, m-, p-硝基甲苯三种异构体在双(对己氧基苯甲酸)对苯二酚酯(PBH~xB)和双(对庚氧基苯甲酸)对苯二酚酯(PBH~pB)两种向列液晶固定液中无限稀薄条件下的活度系数, 进而求得了超额焓, 超额自由能和超额熵, 同时得到溶解焓和溶解熵, 并对结果进行了分析和讨论。     

N-叔丁氧羰基-3-羟基-1-金刚烷基甘氨酸的合成

以金刚烷甲酸(1)为起始原料,经过酰化,取代,脱羧三步反应一锅法制得金刚烷甲基酮(2),然后氧化甲基得到1-金刚烷基乙醛酸(3),将3与盐酸羟氨反应得到1-金刚烷乙醛酸肟(4),还原4并用BOC酸酐保护氨基得到N-叔丁氧羰基-1-金刚烷基甘氨酸(5),最后经高锰酸钾氧化得到DPP-IV抑制剂沙格列汀中间体N-叔丁氧羰基-3-羟基-1-金刚烷基甘氨酸(6),总收率28%。     

羟基铝溶液及铝交联蒙脱土的研究

本文用(27)~Al NMR法和8-羟基喹啉萃取法分别研究了羟基铝溶液中十三聚铝含量的变化规律,还用X-射线衍射法研究了铝交联蒙脱土d_(001)的变化。研究结果表明,铝离子的聚合情况主要由羟铝比决定,而浓度影响不大。随着羟铝比的增加,溶液中单核铝离子含量减少,十三聚铝离子相对含量增加,所得铝交联蒙脱土的d_(001)也随之增大。参照这些变化规律、控制羟基铝溶液的组成,可以制备各种层柱状铝交联蒙脱土复合物。     

可生物降解聚[(对羟基苯甲酸甲酯/甘氨酸乙酯)膦腈]的合成及其体外降解

以PCl5和NH4Cl为原料,利用一锅法制备了聚二氯膦腈,通过两步亲核取代反应,分别以甘氨酸乙酯和对羟基苯甲酸甲酯为亲核试剂,合成了混合取代可生物降解聚[(对羟基苯甲酸甲酯/甘氨酸乙酯)膦腈].用核磁共振波谱及红外光谱等对产物结构进行了表征.研究了甘氨酸乙酯和对羟基苯甲酸甲酯的比例及外界环境对所制备的聚膦腈降解性能的影响,并进行了体外降解实验.研究结果表明,通过改变甘氨酸乙酯和对羟基苯甲酸甲酯的比例,可获得一种降解速率可调节的生物降解膦腈聚合物.     

Effects of pressure on the kinetics of the dehydration of carbonic acid and the hydrolysis of CO2 in aqueous solution

The pressure dependence of the dehydration reaction of H₂CO₃ was measured in acidic aqueous solution for pressures up to 1 kbar using a high-pressure stopped-flow instrument. The corresponding volume of activation was found to be 6.4±0.4 cm³-mol^–1 at 25°C and 0.5 ionic strength. Volume equation calculations result in a value of –9.9±1.9cm³-mol^–1 for the volume of activation for the hydrolysis of CO₂ under the same conditions. For the first time, the reaction mechanism can be interpreted in terms of dissociative and associative modes, respectively. These data are used to construct an overall reaction volume profile.     

Thermodynamics of lonization of aqueous lodic acid,an “almost-strong” electrolyte

We have made calorimetric measurements of enthalpies of dilution of aqueous iodic acid and have used these results for evaluation of the standard enthalpy of ionization of HIO₃(aq.). We have also made calorimetric measurements of enthalpies of addition of perchloric acid solution to aqueous solutions of KIO₃, KNO₃, NaIO₃, and NaNO₃ and have used these results to obtain further values for the standard enthalpy of ionization of HIO₃(aq.). On the basis of all these results, we have selected H^o=–660±125 cal-mole^–1 as the best available standard enthalpy of ionization of HIO₃(aq.) at 298.15°K, compared to the previously accepted –2400 cal-mole^–1. Using the best available K=0.157 for ionization, we also obtain G^o=1097 cal-mole^–1 and S^o=–5.9 cal-^oK^–1-mole^–1 for ionization of HIO₃(aq) at 298.15°K.On study leave from Department of Inorganic and Analytical Chemistry, LaTrobe University, Bundoora, Victoria, 3083, Australia, to University of Lethbridge.On study leave from Department of Chemistry, University of Wollongong, Wollongong, N.S.W. 2500, Australia, to University of Lethbridge.     

氨基酸季铵离子液体水溶液的密度和黏度

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Ionic radii in aqueous solutions

The aqueous ionic radii of 35 ions have been calculated from published data of the average distances between the ions and the nearest water molecules, obtained by diffraction and computer simulation methods.     

The Soret effect with chemical reaction in aqueous sulfuric acid solutions

The Soret coefficient of aqueous sulfuric acid has been determined conductimetrically from 0.0005 to 0.2m at 25°C. The derived enthalpies of transport increase sharply as the concentration drops, approaching a limiting value near 35 kJ-mol^–1. The increase, in the enthalpy of transport at low concentrations is due to the large intrinsic enthalpies of transport of the hydrogen and sulfate ions that are produced by the dissociation of bisulfate ions. The enthalpy of dissociation of the bisulfate ions reduces the acid's enthalpy of transport by up to 1.8 kJ-mol^–1.     

On the properties of surfactant aqueous solutions

Summary From studies of aqueous solutions of dodecylammoniumnitrate an association mechanism has been proposed involving multiequilibrium. In the concentration range considered we can differentiate between two aspects: ranges of marked qualitative and quantitative changes and formation of differently structured surfactant species.

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Zusammenfassung Aus der Untersuchung wäßriger Lösungen von Dodecylammoniumnitrat würde ein Assoziationsmechanismus abgeleitet, welcher ein Multiequilibrium beinhaltet. Im untersuchten Konzentrationsbereich können zwei Bereiche unterschieden werden: Bereiche mit ausgeprägten qualitativen und quantitativen Änderungen und Bereiche mit der Bildung von verschieden strukturierten oberflächenaktiven Spezies.

     

Enthalpies of solution of glycine in aqueous solutions of 1,2-diols and glycerol at 25°C

Dissolution enthalpies of glycine in mixtures of water with 1,2-ethanediol, 1,2-propanediol, 1,2-butanediol, 1,2-pentanediol, 1,3-propanediol and glycerol have been measured at 25°C. The enthalpic pair interaction coefficients of the glycine zwitterion with the polyalcohol molecule have been determined by using the standard solution enthalpies of glycine in water and in aqueous solutions of the polyalcohols. The values of the resultant enthalpic interaction coefficients are interpreted assuming a criterion in the form of the effect of hydrophobic alkyl radicals on the interactions between the hydroxyl groups of polyalcohols and the zwitterion of glycine.     

Kinetics of hydrolysis of xylometazoline (XYL) in aqueous solution

The effect of pH (over the range of 2.10 - 11.90) and temperature (from 353 K to 363 K) on the stability of xylometazoline (XYL) has been studied by high performance liquid chromatography (HPLC). Using the dependence of log k vs pH, the hydrolysis of both the undissociated and dissociated XYL-molcules has been described by micro rate constants k₁ and k₂. Thermodynamic parameters (activation energy, enthalpy and entropy) of the composition reaction were calculated. This revised version was published online in June 2006 with corrections to the Cover Date.     

Structure and properties of novel fibers spun from cellulose in NaOH/thiourea aqueous solution

Cellulose was dissolved rapidly in a NaOH/thiourea aqueous solution (9.5:4.5 in wt.-%) to prepare a transparent cellulose solution, which was employed, for the first time, to spin a new class of regenerated cellulose fibers by wet spinning. The structure and mechanical properties of the resulting cellulose fibers were characterized, and compared with those of commercially available viscose rayon, cuprammonium rayon and Lyocell fibers. The results from wide angle X-ray diffraction and CP/MAS 13C NMR indicated that the novel cellulose fibers have a structure typical for a family II cellulose and possessed relatively high degrees of crystallinity. Scanning electron microscopy (SEM) and optical microscopy images revealed that the cross-section of the fibers is circular, similar to natural silk. The new fibers have higher molecular weights and better mechanical properties than those of viscose rayon. This low-cost technology is simple, different from the polluting viscose process. The dissolution and regeneration of the cellulose in the NaOH/thiourea aqueous solutions were a physical process and a sol-gel transition rather than a chemical reaction, leading to the smoothness and luster of the fibers. This work provides a potential application in the field of functional fiber manufacturing.     

Excess enthalpies and apparent molar volumes of some N-methyl substituted amino acids in aqueous solutions

The excess enthalpies and limiting partial molar volumes at 25°C for aqueous solutions of N-methyl glycine, N-methyl alanine, and N-methyl serine are reported and compared with the same properties for the parent amino acids. For each N-methyl derivative the enthalpic contribution to the pairwise interaction is less favorable than that for the parent amino acid. The contribution of the N-methyl substituent to V ₂ ⁰ is similar for each amino acid, and is about 2 cm³-mol^–1 greater than for a methyl substituent on the -carbon. These observations have been rationalized in terms of the likely solute-solvent interactions. In addition a rigid particle model is used with the volume data to examine solute-solvent interactions.