PREPARATION OF EVOH MICROPOROUS MEMBRANES via THERMALLY INDUCED PHASE SEPARATION USING BINARY SOLVENTS

Microporous ethylene-vinyl alcohol copolymer （EVOH） flat membranes and hollow-fiber membranes with 38 mol% ethylene content were prepared via thermally induced phase separation （TIPS） using the mixture of 1,4-butanediol and poly（ethylene glycol）（PEG400） as diluents. Effects of the ratio of 1,4-butanediol to PEG400 on the phase diagrams, phase separation mechanism and membrane morphology were studied by small angle light scattering （SALS） measurements, differential scanning calorimetry （DSC）, and scanning ele~：tron microscopy （SEM）. It was found that by varying the composition of the binary solvent, the phase diagrams and membrane morphology can be controlled successfully. Moreover, the phase diagrams showed that broader regions of Liquid-Liquid （L-L） phase separation were obtained, as well as closer distances between L-L phase separation lines and Solid-Liquid （S-L） phase separation lines, Interconnected structures observed both in the flat membrane and hollow fiber membrane consist with the above results.

Preparation of PLA and PLGA nanoparticles by binary organic solvent diffusion method

The nanoparticles of polylactide (PLA) and poly(lactide-co-glycolide) (PLGA) were prepared by the bi-nary organic solvent diffusion method. The yield, particle size and size distribution of these nanoparticles wereevaluated. The yield of nanoparticles prepared by this method is over 90%, and the average size of the nanoparticlesis between 130-180 nm. In order to clarify the effect of the organic solvent used in the system on nanoparticle yieldand size, the cloud points of PLA and PLGA were examined by cloud point titration. The results indicate that theyields of nanoparticles increase with the increase of ethanol in the acetone solution and attain the maximum at thecloud point of ethanol, while the size of nanoparticles decreases with the increase of ethanol in the acetone solutionand attains the minimum at the cloud point of ethanol. The optimal composition ratio of binary organic solvents coin-cides to that near the cloud point and the optimal condition of binary organic solvents can be predicted.

Preferential solvation of pomalidomide,an anticancer compound,in some binary mixed solvents at 298.15 K

Preferential solvation of pomalidomide(PMD)was explored in dimethyl sulfoxide(DMSO)-dimethylformamide(DMF),DMSO-tetrahydrofuran(THF),DMSO-methanol(Me OH),DMSO-isopropanol,DMSO-water,water-DMF,water-THF,water-Me OH,and water–isopropanol binary mixed solvents at 298.15 K.Bosch-Rose model was utilized to determine the electronic transition energies(ET)and other preferential solvation parameters,describing solute-solute and solute-solvent interactions.We found thatλmaxsituation shifted with dielectric constant of the pure solvents meaningfully.According to the obtained results,ETenhanced andλmaxshifted to the lower wavelengths as the percentage of DMSO decreased in the binary mixtures,remarking the important role of DMSO for stabilizing the excited state(π*)of PMD chromophore via efficient intermolecular solute-solvent interactions.In addition,the aqueous binary systems showed an optimum point for the ETvalues as the percentage of water changed in the solutions.The local mole fraction of the solvents in the cybotactic region was also estimated to describe the specific and non-specific interactions in the systems.

A^1HNMR STUDY ON THE FORMATION AND BREAKING OF INTRAMOLECULAR HYDROGEN BONDS OF BILIRUBIN IN CDCl_3-DMSO-d_6 BINARY SOLVENT

The formation and breaking of intramolecular hydrogen bonds of bilirubin in CDCl_3-DMSO-d_6 binary solvent have been investigated by means of NMR spectroscopy.The chemical shifts of protons at dipyrrinone lactam C=O and N-H,Pyrrole N-H,C-5,C-15 and methylene groups of 8,12-propionic acid side-chains changed markedly as a function of composition of the binary solvent.The hydrogen bond formation is dependent on the conformation of propionic acid side-chains.

Solvent effects on infrared spectra of 2—Methyl—4,5—dimethoxy—3—oxo—2H—Pyridizine：Part 2.Binary Solvent SYstems

This research on the solvent effects of 2-methyl-4,5-dimethoxy-3-oxo-2H-pyridizine(MDOP) in binary solvent systems on the infrared spectra for MDOP in n-hexane/CHCl3 mixture solvents showed that there were three forms of carbonyl stretching vibration band[v(C=O)] of MPOP as mole fraction of CHCl3 in the binary solvents changes.In pure n-hexane solvent,the v(C=O) of MODP appeared at a relatively high wavenumber.With CHCl3 added,the v(C=O) shifted to lower wavenumbers.Two new bands were observed over a certain range of mixture solvent compositions.The origin of the bands was discussed in the terms of two kinds of hydrogen bond together with their individual dependence on mixture composition.COmparisons were drawn for the solvent sensitivities of v(C=O) for propanone.

Water Sorption Behaviors of Novel Biohybrid Hydrogels as Effective Sorbents in Water-Solvent Binary Mixtures

Novel sorbent hydrogels containing acrylamide/sodium vinylsulfonate, carboxymethyl cellulose and zeolite were synthesized with free radical solution polymerization by using ammonium persulfate/N,N,N’,N’-tetramethylethyle-nediamine as redox initiating pair in presence of poly(ethylene glycol) diacrylate as crosslinker. It was to investigate the water uptake properties of series of the novel hydrogels, the semi IPNs and the hybrid/biohybrid composite hydrogel sorbents synthesized in this study. Water uptake studies were performed in water and in water-solvent (acetone, methanol and tetrahydrofuran) binary mixtures at 25°C, gravimetrically. Some swelling and diffusion parameters were calculated and discussed. It has been seen that the lower equilibrium swelling factor values in all solvent compositions in comparison with the equilibrium swelling factor values in water.

Determination of physical properties for the mixtures of [BMIM]Cl with different organic solvents

Physical properties including refractive index, density, viscosity and conductivity for binary mixtures of 1-butyl-3-methyl imidazolium chloride([BMIM]Cl) and different organic solvents at 298.15 K have been investigated. Excess molar volumes have been calculated and obtained data has been fitted by the Redlich–Kister equation. The density and refractive index were found to increase with increasing concentration of [BMIM]Cl, however, exceptions do exist as in the case of dimethyl sulfoxide(DMSO)/[BMIM]Cl. For DMSO/[BMIM]Cl, the density decreases with increasing concentration. The addition of different organic solvents was able to disrupt the interactions within mixtures, leading to free mobility of ions. The free mobility of ions has been found to enhance conductivity and decrease viscosity to varying extents in all mixtures studied. It has been observed that solubility parameters,dielectric constants and composition of the solvents used play a vital role in determining the resultant properties.The data obtained will play an important role in understanding the effect of the addition of organic solvents in ILs to enhance their applicability.

用NRTL方程计算含离子液体体系的汽液平衡

离子液体作为环境友好溶剂在反应和分离过程中具有良好的应用前景, 含离子液体体系汽液平衡的计算及模型化研究具有重要的理论和实际意义. 采用非电解质溶液NRTL 方程表示溶液的非理想性, 关联了[bmim] [PF6] H2O及[C8mim] [PF6] H2O二元体系的等温汽液平衡, 关联误差在2%之内; 预测了这些体系在其他温度下的汽液平衡, 预测的总平均误差均在5%之内. 通过关联不同温度下有机物在离子液体C8H14S2O4F6N3 和C9H16S2O4F6N3 中的无限稀释活度因子的实验数据, 得到了有关NRTL方程的二元作用参数, 在此基础上预测了离子液体对二元共沸体系汽液平衡的影响. 结果表明, 含离子液体体系的汽液平衡可以采用传统的非电解质溶液模型如NRTL方程来描述, 离子液体的“盐效应”可以显著改善组分的相对挥发度甚至消除共沸现象.

含水介质中N-苯甲酰胺基-N′-苯基硫脲衍生物识别阴离子研究

设计合成了三种N 取代苯甲酰胺基 N′ 苯基硫脲 ,应用吸收光谱考察了CH3 CN以及 1%～ 10 %H2 O CH3 CN溶液中其与CH3 CO-2 ,H2 PO-4,HSO-4,ClO-4,Cl-和Br-等阴离子的相互作用 .结果表明 ,该类主体分子与阴离子形成氢键配合物 ,溶液由无色转变为黄色 .通过改变苯甲酰基上的取代基可有效调控识别结合作用的选择性 ,在含水介质中苯甲酰基上对乙氧基取代的主体分子可高选择性识别CH3 CO-2 .探讨了主客体之间的作用机理 ,并用于水相中无机醋酸盐的直接显色测定 .

萃取精馏分离苯和环己烷的二元混合溶剂

混合溶剂萃取精馏技术是一种极具发展潜力的新型分离技术．通过一个简单实用的气液平衡实验装置考察了多个萃取精馏分离苯／环已烷近沸点体系的二元混合溶剂:二甲基亚砜和N,N-二甲基甲酰胺、二甲基亚砜和 N-甲基吡咯烷酮以及N-甲基吡咯烷酮和N,N-二甲基甲酰胺的性能．结果发现,混合溶剂分离效果比简单溶剂更好,且混合溶剂存在最佳组成;当混合溶剂的摩尔比接近1时,其性能最佳;N,N-二甲基亚砜和N,N-二甲基甲酰胺组成的混合溶剂是所有被考察萃取剂中最好的混合溶剂;另外还发现了优于文献报道的简单溶剂N,N-二甲基甲酰胺．

逆电渗析法热-电转换系统循环工质匹配准则

将开式逆向电渗析法浓差能发电技术原理与吸收式制冷/热泵系统循环原理相结合,提出了一种全新的闭式热-电循环转换方法,且发现工作介质(溶质与溶剂混合物)是影响该系统能量转换效率的关键因素之一。以9种溶质(一价无机盐)和17种溶剂(标准沸点温度在40~150℃)为研究对象,通过分析工质的13项关键物性参数(沸点温度、汽化潜热、比热容、溶解度、偏心因子、偶极矩、相对介电常数、电导率、黏度、热导率、燃爆极限、自动点火温度及毒性),建立了从热力学性质、电化学性质、输运特性、危险性等多角度来综合评价热-电循环转换系统工质匹配性的准则,并据此推断无机盐-溶解剂-调节剂三元混合物极具发展潜力。

煤在含有吡啶的二元溶液中吸附和溶胀行为的研究(英文)

本实验采用WK11模型化合物及ND褐煤和IL烟煤,在含有吡啶的水、环己烷、甲苯双溶液系统中研究其吸附和溶胀行为。研究结果显示,在稀溶液条件下吡啶吸附量和溶胀率都很低,而且即使在很长的反应时间内溶液中的吡啶也不能被全部吸附。这表明虽然由于热力学有利的熵变,吡啶可以断开煤中所有的氢键交联结构而形成新的氢键,但溶剂环境的影响和孔径等因素的扩散限制,也显著影响煤的吡啶吸附量和溶胀行为。在低吡啶浓度时,煤的溶胀率与吸附量无线性关系。在高吡啶浓度时,溶胀率随吸附量的增大而增加。但吡啶浓度超过一定值时,由于吡啶的强抽提作用,一定反应时间后煤和溶剂界面消失。

1,2-环己二醇溶解度的测定及关联

采用激光监视技术测定了 1,2 环己二醇在乙酸甲酯、乙酸乙酯、乙酸丙酯、乙酸丁酯、丙烯酸甲酯、丙烯酸乙酯、甲基丙基酮、乙酰乙酸乙酯和水中的溶解度 ,并用UNIFAC模型进行了关联 ,其溶解度预测值与实测值吻合良好 .

二元溶剂分散法制备PLA和PLGA纳米粒

用二元溶剂分散法制备不同分子量、单体比 (L G ,共聚物聚丙交酯乙交酯 (PLGA)中乳酸 (lactide)与乙醇酸 (glycolide)的质量比 )的共聚物PLGA和聚乳酸 (PLA)的纳米粒。考察了制备方法对纳米粒产率、粒径及粒径分布的影响。通过冷冻干燥可获得具有窄粒径分布的聚合物纳米粒。用浊点滴定法探讨了乙醇和丙酮对纳米粒粒径和产率的影响。研究表明 ,纳米粒产率随丙酮溶液中乙醇量的增加而提高 ,并当乙醇量接近浊点值时达最大 ,而纳米粒粒径却随丙酮溶液中乙醇量的增加而减小 ,并当乙醇量接近浊点值时达最小。因此 ,可用浊点实验确定制备具有较高产率和较小粒径的聚合物纳米粒的最优条件。PLA和PLGA 2种聚合物的纳米粒产率均大于 90 % ,平均粒径在 130～ 180nm之间。

均匀设计优化二元溶剂分散法制备莪术油纳米粒的研究

目的优化二元溶剂分散法制备莪术油纳米粒(ZTO-NP)的制备工艺技术条件,探讨其可行性。方法以形态、粒径、包封率为指标,采用均匀设计,考察分散剂浓度、载体材料用量、有机相体积和搅拌时间等影响因素,筛选出比较理想的制备工艺。结果最佳工作条件为:聚氧乙烯-聚氧丙烯共聚物(普朗尼克F68)0.1%,乳酸-乙醇酸共聚物(PLGA)0.01 g,搅拌时间4 h,丙酮体积1 mL。所制得的纳米粒为圆整的类球形粒子,表面光滑,平均粒径为233.1 nm(PDI值为0.047),zeta电位为-22.1 mV,包封率为70.01%,载药量为57.55%。结论二元溶剂分散法可用于莪术油类液体药物纳米粒的制备。

有机-水溶剂体系中草酸锰结晶行为及其热分解特性的研究

The mineral of manganese oxalate dihydrate was synthesized in aqueous and organic-water binary solvent system (OWBS), respectively. The samples were characterized by XRD and SEM. The results show that OWBS can effectively control the phase and morphology of manganese oxalate dihydrate. The distinction of thermal decompositon of monoclinic and orthogonal manganese oxalate dihydrate can be ascribed to the different linkage mode of manganese cation, oxalate anion and crystallized water in inter-molecules. The kinetic parameters of thermal decomposition were obtained by TG-DTA curves in various scan rates, and notably, porous manganese oxide was prepared from orthogonal manganese oxalate.

含水介质中苯甲醛缩氨基硫脲对H_2PO_4^-的识别作用研究

利用紫外-可见吸收光谱研究了苯甲醛缩氨基硫脲受体分子对H2PO4-和Cl O3-的选择性识别作用。结果表明,该受体分子对H2PO4-有较好的识别作用,而对Cl O3-没有作用。随着溶液中含水量的增加,受体对H2PO4-的识别作用减弱,证明了受体分子与阴离子之间形成了氢键加合物。可用于无机盐磷酸二氢根的检测。

中国白酒的电导率及与品质控制的关系

对乙醇浓度、存放时间、温度以及酸和酯等因素对白酒溶液的电导率影响进行了实验研究。结果表明:随着乙醇浓度增大,其电导率基本上呈下降趋势,同时酒的存放时间、温度以及酸和酯也对白酒的电导率产生显著影响,并呈现一定的规律性,这些规律和现象的认识,为以电导率作为白酒生产工艺和品质控制的技术参数提供了科学的依据。

二相系涂层液溶剂扩散数值模拟进展

为了预测二相系涂料成膜过程中溶剂浓度的变化以及最终的成膜质量,建立二相系涂层液溶剂扩散系数的模型以及二相系涂层液干燥过程的模型并进行数值模拟,对于指导涂层的制备及优化设备构造具有非常重要的意义。综述了近年来关于计算溶剂-聚合物涂层液二相系统中溶剂扩散系数的数学模型,以及建立溶剂-聚合物涂层液干燥模型进行数值模拟的进展,并分析了目前关于溶剂扩散系数模型与溶剂-聚合物二相系涂层干燥模型及数值模拟研究中存在的问题。提出在创建二相系涂层干燥模型时,要更加全面地考虑基体与涂层液的性质、涂膜收缩率以及涂膜温度变化等因素,进一步完善涂层干燥模型,提高模拟计算的准确度。对溶剂扩散系数模型与溶剂-聚合物二相系涂层干燥模型,分别提出了有效的实验验证方法,为验证模型的准确性提供了可能。预测溶剂-聚合物涂层液二相系在烘干过程中溶剂的扩散行为,可增强对涂层成膜过程的认识,且有益于节能环保地进行涂层产品的设计及涂层工艺的优化。

乙二醇和水混合溶剂热法控制合成LiFePO_4及其性能研究

水热法和溶剂热法是合成制备锂离子电池正极材料磷酸铁锂(LiFePO4)最常用的方法,但由于单一溶剂具有的自身缺陷使其在应用方面受到了一定的限制。而水和有机溶剂的混合溶剂热法则是在水/溶剂热法的基础上,充分利用水和有机溶剂各自的理化性质发展起来的有效方法。本文中我们选取乙二醇(EG)和水(H2O)组成二元混合溶剂来控制合成LiFePO4正极材料,并成功地获得了结构形貌规则和颗粒分散均匀的样品材料。然后,通过X射线衍射(XRD)、场发射扫描电子显微镜(FESEM)和电化学性能测试等手段,对获得的样品活性材料进行了表征和测试。结果显示采用混合溶剂热法获得的LiFePO4样品材料具有更好的结构形貌和电化学性能。