离子液体[bmim]BF4与溶剂DMS0相互作用的研究

在298.1～323.15 K范围内,测定了1-丁基-3-甲基咪唑四氟硼酸盐离子液体([bmim]BF4)与DMSO混合体系的密度和粘度,研究发现:随着DMSO加入量的增加,混合体系的密度和粘度均减小.在此条件下,计算了此离子液体的粘度活化参数,η∞、Ea、性粘度B-系数及过量对数粘度,结果表明:Ea与DMSO的摩尔分...     

[bmim][BF_4]、[bmim][PF_6]离子液体及其与DMF二元体系在293.15～338.15K下的粘度

为获得离子液体与有机物物理性质的数据,常压下,293.15～338.15 K温度范围内,分别测定了1-丁基-3-甲基咪唑四氟硼酸盐（[bmim][BF4]）、1-丁基-3-甲基咪唑六氟磷酸盐（[bmim][PF6]）2种咪唑类离子液体以及它们和N,N-二甲基甲酰胺（DMF）构成的2个二元体系的粘度,采用Vogel-Tamman-Fulcher（VFT）方程和Arrhenius-like方程对所测粘度数据进行关联。结果表明,同一温度下,3种纯溶液粘度大小顺序依次为：DMF〈[bmim][BF4]〈[bmim][PF6]。[bmim][BF4]、[bmim][PF6]离子液体及其与DMF构成的二元体系的粘度均随着温度的升高和DMF摩尔分率的增加而降低。实验条件下,DMF＋[bmim][BF4]和DMF＋[bmim][PF6]二元体系的粘度变化范围分别为1.26～125.5 MPa·s和1.11～165.7 MPa·s。VFT方程对于DMF-[bmim][BF4]与DMF-[bmim][PF6]体系的关联结果比Arrhenius-like方程较好,其总平均绝对误差、总平均相对误差、以及总平均标准方差分别为0.561 9 MPa·s和0.918 6 MPa·s、0.026 8 MPa·s和0.020 9 MPa·s、0.725 5 MPa·s和1.125 1 MPa·s。     

离子液体-水体系的相平衡

通过对1-丁基-3-甲基咪唑四氟硼酸盐([bmim][PF4])离子液体 水体系相平衡及NaCl、NaBF4和氯化1-丁基-3-甲基咪唑([bmim]Cl)对离子液体 水体系相平衡的影响进行了研究,结果表明: 离子液体[bmim][BF4] H2O二元体系具有典型的最高上临界溶解温度(UCST)行为,其最高上临界温度为5.3℃左右,临界组成为50%(水的质量分数); NaCl和NaBF4降低 [bmim][BF4] H2O体系的混溶性,而[bmim]Cl增加该体系的混溶性.由此得到一种简单定性地判断离子液体[bmim][BF4]中可能存在的杂质种类和水平的方法,并利用此结果可设计纯化该离子液体的绿色工艺.     

丙烯酰胺在离子液体中的聚合反应研究

以四氟硼酸1-丁基-3-甲基咪唑([bmim]BF4)离子液体为反应溶剂,以过氧化苯甲酰-N,N-二甲基苯胺氧化还原体系为引发剂引发聚合了丙烯酰胺。采用粘度法测定了聚丙烯酰胺的相对粘均分子量,考察了聚合反应时间、反应温度、引发剂浓度对聚合物分子量和聚合反应单体转化率的影响。结果表明,丙烯酰胺可以在[bmim]BF4离子液体中进行氧化还原聚合,聚合物分子量随反应温度的升高而下降,聚合反应速率随着温度的升高而升高,得到的聚丙烯酰胺分子量可高达7.32×107以上,且水溶性良好。     

TiCl_4在离子液体[emim]BF_4及[bmim]PF_6中的电化学性能

在[emim]BF4离子液体中Pt片电极上通过恒电位电沉积制备出金属Ti。采用液/液连续萃取方法对亲水性离子液体[emim]BF4进行提纯,高纯水多次洗涤方法对疏水性离子液体[bmim]PF6进行提纯。在[emim]BF4和[bmim]PF6两种离子液体中研究了Ti Cl4的循环伏安,在含有Ti Cl4的[emim]BF4离子液体中,研究了Pt片电极上的恒电位电沉积。结果表明,连续萃取方法提纯[emim]BF4及高纯水多次洗涤[bmim]PF6,可使两种离子液体纯度分别达到实验要求;在离子液体[emim]BF4中,在Pt片电极上,在-1.8 V(vs Pt)下电解2 h,沉积物中的Ti含量达82.8%。     

TiCl_4在离子液体[emim]BF_4及[bmim]PF_6中的电化学性能

在[emim]BF4离子液体中Pt片电极上通过恒电位电沉积制备出金属Ti。采用液/液连续萃取方法对亲水性离子液体[emim]BF4进行提纯,高纯水多次洗涤方法对疏水性离子液体[bmim]PF6进行提纯。在[emim]BF4和[bmim]PF6两种离子液体中研究了Ti Cl4的循环伏安,在含有Ti Cl4的[emim]BF4离子液体中,研究了Pt片电极上的恒电位电沉积。结果表明,连续萃取方法提纯[emim]BF4及高纯水多次洗涤[bmim]PF6,可使两种离子液体纯度分别达到实验要求;在离子液体[emim]BF4中,在Pt片电极上,在-1.8 V(vs Pt)下电解2 h,沉积物中的Ti含量达82.8%。     

离子液体1-甲基-3-乙基咪唑四氟硼酸盐和1,2-二甲基-3-乙基咪唑四氟硼酸盐的热力学和电导性质研究

在室温下合成了离子液体1-甲基-3-乙基咪唑四氟硼酸盐([Emim]BF4)和1,2-二甲基-3-乙基咪唑四氟硼酸盐([Dmeim]BF4),通过红外光谱对其进行了结构表征。分别测定了两种离子液体在不同温度下的密度、表面张力、粘度和电导率,发现当咪唑环2位碳上增加甲基取代基后其密度、表面张力和电导率均呈下降趋势,而粘度呈上升趋势且变化较大,如在298.15 K时[Emim]BF4的粘度为842 mPa.s,[Dmeim]BF4的粘度为8 293 mPa.s。并根据特定的经验方程估算了两种离子液体的热膨胀系数、摩尔体积、标准熵和晶格能等重要的性质参数。     

SO2／离子液体体系热力学性质的分子动力学模拟

为研究SO2对咪唑类普通离子液体输运特性、体积的影响,本文通过分子动力学方法模拟了293．15K时,常压下[bmim][PFs]和[bmim][BF4]与soz的？昆合物。结果表明,咪唑类普通离子液体的扩散系数随气体溶质摩尔分数的增加而增大,粘度则相应减小。吸收SO2对离子液体体积的影响极小。混合物摩尔体积随SO2摩尔分数增加呈直线下降。     

1-丁基-3-甲基咪唑四氟硼酸盐离子液体的合成与表征

以N-甲基咪唑和1-溴代正丁烷为原料,两步合成法制备了离子液体[bmim]BF4。考察了反应时间、反应温度、原料配比对中间体1-丁基-3-甲基咪唑溴盐[bmim]Br收率的影响和离子交换时间和离子交换温度对目标产物[bmim]BF4产率的影响。结果表明:①合成中间体[bmim]Br的最佳条件为:反应温度65℃,反应时间16 h,N-甲基咪唑与1-溴代正丁烷的摩尔比为1∶1.1,产品收率可达94.8%;②合成离子液体的最佳条件为:反应温度65℃,反应时间24 h。     

金属Al和不锈钢在[bmim]BF_4离子液体中的电化学

离子液体作为有潜力的绿色电化学介质,在电解、电镀、电催化、电分析化学等领域具有非常好的应用前景.本文采用循环伏安法和塔夫尔曲线法研究了金属Al和不锈钢在[bmim]BF4离子液体中的电化学行为,结果表明金属Al在[bmim]BF4离子液体中非常稳定,不锈钢在该离子液体中显示一定的活性.     

BuNENA/DMSO二元体系密度、黏度测定及关联

利用密度瓶和乌氏黏度计分别测定了25,40,50,70℃时BuNENA/DMSO二元体系的密度、黏度,并对黏度与温度、组成的关系进行了多项式回归,模型计算值平均相对误差在0.17%—1.53%。由密度数据计算出超额摩尔体积VmE,由黏度数据计算出不同温度、组成下的超额黏度Δη,其中VEm为正值,Δη为负值。对混合液在不同温度下的VmE与组成的关系用Redlich-Kister方程进行了关联,平均相对误差小于3%。     

二元混合物环丁酚和对二甲苯、乙苯在温度范围为303.15—353.15K下的密度、黏度及其相关性质

Densities and viscosities of the binary systems of sulfolane ＋ ethylbenzene, sulfolane ＋ p-xylene have been experimentally determined in temperature interval 303.15—353.15 K and at atmospheric pressure for the whole composition range. The excess molar volumes and viscosity deviations were computed. The computed quantities have been fitted to Redlich-Kister equation. Excess molar volumes and viscosity deviation show a systematic change with increasing temperature. Two mixtures exhibit negative excess volumes with a minimum which occurs approximately at χ = 0.5. The effect of the size, shape and interaction of components on excess molar volumes and viscosity deviations is discussed.     

二元混合物环丁酚和对二甲苯、乙苯在温度范围为303.15-353.15K下的密度、黏度及其相关性质

Densities and viscosities of the binary systems of sulfolane ethylbenzene, sulfolane p-xylene have been experimentally determined in temperature interval 303.15-353.15 K and at atmospheric pressure for the whole composition range. The excess molar volumes and viscosity deviations were computed. The computed quantities have been fitted to Redlich-Kister equation. Excess molar volumes and viscosity deviation show a systematic change with increasing temperature. Two mixtures exhibit negative excess volumes with a minimum which occurs approximately at x = 0.5. The effect of the size, shape and interaction of components on excess molar volumes and viscosity deviations is discussed.     

Rheogoniometry of molten blends of polystyrene and styrenic ionomers

The rheological properties of the molten blends between polystyrene (PS) and styrenemethacrylic acid copolymer (S-MAA) or its metallic salts were determined with a Weissenberg rheogoniometer, and the mixed structure and the processability were discussed. Results were as follows. (1) The viscosities of the salts increased and the compliances decreased with increasing density of ionic crosslinkings. (2) The viscosities of the molten blend between PS and S-MAA or its salt increased steeply even at lower shear rate and the Newtonian flow region was not observed. (3) This shear-sensitivity of viscosity in low shear rate region increased with increasing temperature. (4) The effect of temperature on the viscosity of these blends deviated from the simple Arrhenius plot. (5) Some network structures are suggested for the blends between PS and S-MAA salts but they may be broken eventually under high shear rate or at high temperature. Therefore, the mixed structures and the flow mechanisms of these molten blends seem to change with shear or temperature.     

纤维素原料/离子液体溶液体系流变性能的研究

利用NDJ-1型旋转粘度计分别对木浆/离子液体氯化1-丁基-3-甲基咪唑([BMIM]Cl)溶液体系和水洗汽爆麦草/[BMIM]Cl溶液体系的流变性能进行了研究。考察了转子转速、温度、纤维素浓度及添加剂等对溶液粘度的影响。结果表明,两种溶液体系的流动活化能均较低,分别为42 kJ/mol和47 kJ/mol,其表观粘度随温度升高而降低;纤维素浓度和浆粕聚合度的增加都可使溶液的粘度增加。进一步研究了不同添加剂对粘度的影响,发现二甲基亚砜(DMSO)、N,N-二甲基乙酰胺(DMAC)和1,4-二氧六环的加入都能降低溶液的粘度,但以DMSO的效果最佳。     

氯盐离子液体水溶液的物理化学性质

离子液体是一类新型表面活性剂,研究离子液体+水体系的物性具有重要的意义。为此,本文测定了不同浓度和温度下［Bemim］［Cl］（氯化-1-甲基-3-苄基咪唑）,［C_nmim］［Cl］（氯化-1-甲基-3-烷基咪唑, n=4,14,16）,［BeiQu］［Cl］（氯化-N-苄基异喹啉）,［C_miQu］［Cl］（氯化-N-烷基异喹啉, m=4,8）等氯盐离子液体水溶液的密度、动力黏度、表面张力等物化性质。氯盐离子液体水溶液密度的变化趋势为咪唑类>异喹啉类。离子液体水溶液的黏度随着温度的升高而减小,随着浓度的升高而升高。在等温条件下,阳离子取代基相同时,离子液体水溶液的表面张力的变化趋势为咪唑类<异喹啉类。     

New aspects of viscosity effects on the photopolymerization kinetics of the 2,2‐bis[4‐(2‐hydroxymethacryloxypropoxy)phenyl]propane/triethylene glycol dimethacrylate monomer system

The photopolymerization kinetics and viscosity behavior of 11 2,2‐bis[4‐(2‐hydroxymethacryloxypropoxy)phenyl]propane/triethylene glycol dimethacrylate mixtures were investigated. The viscosity was studied at six temperatures (20–70°C), and the activation energies for the viscosity were determined. The excess logarithm viscosities were calculated and found to be negative over the whole composition and temperature ranges; they were fitted to the Redlish–Kister polynomial equation. The kinetic analysis of the photopolymerization was carried out at three polymerization temperatures (20, 40, and 60°C). The results proved the existence of the most reactive composition (reaching the highest value of the maximum polymerization rate), but the ratio of the monomers in this composition, close to equimolar, showed a tendency to change with the polymerization temperature. The viscosities of the most reactive compositions lay in the range of about 0.1–1.2 Pa s, which was narrow in comparison with the range of viscosities of all the compositions used in the kinetic studies (from 3 × 10^?3 to 1.5 × 10³ Pa s). The activation energies for the polymerization rates were calculated and correlated with the viscosity changes. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Free radical polymerization in ionic liquids—Influence of the IL-concentration and temperature

The influence of the ionic liquid (IL) 1-ethyl-3-methylimidazoliumethylsulfate ([EMIM]EtSO₄) on the polymerization kinetics of methyl methacrylate was investigated. ILs are liquids with relatively high polarities and viscosities. These two characteristic properties are strongly correlated with the rate coefficients of propagation k_p and termination k_t of polymerizations carried out in ILs. The rate constant of termination k_t decreases when the concentration of ionic liquid, and thus the viscosity is increased, whereas the propagation rate coefficient k_p increases with increasing IL content. The viscosity of ILs can be varied by either working with mixtures of ILs with conventional organic solvents – here the IL [EMIM]EtSO₄ was mixed with dimethyl formamide (DMF) – or by variation of the temperature. The studies were carried out to determine the influence of the viscosity on the propagation and the termination reaction as well as the molecular weight distribution.     

Effect of Temperature on the Physico-Chemical Properties of a Room Temperature Ionic Liquid (1-Methyl-3-pentylimidazolium Hexafluorophosphate) with Polyethylene Glycol Oligomer

A systematic study of the effect of composition on the thermo-physical properties of the binary mixtures of 1-methyl-3-pentyl imidazolium hexafluorophosphate [MPI][PF(6)] with poly(ethylene glycol) (PEG) [M(w) = 400] is presented. The excess molar volume, refractive index deviation, viscosity deviation, and surface tension deviation values were calculated from these experimental density, ρ, refractive index, n, viscosity, η, and surface tension, γ, over the whole concentration range, respectively. The excess molar volumes are negative and continue to become increasingly negative with increasing temperature; whereas the viscosity and surface tension deviation are negative and become less negative with increasing temperature. The surface thermodynamic functions, such as surface entropy, enthalpy, as well as standard molar entropy, Parachor, and molar enthalpy of vaporization for pure ionic liquid, have been derived from the temperature dependence of the surface tension values.     

均三甲苯/二异丁基甲醇混合溶剂黏度测定及关联

采用乌氏黏度仪,在常压和293.15～323.15 K温度范围内测定了均三甲苯与二异丁基甲醇混合溶剂以及两种纯溶剂的黏度,计算了不同温度和组成下混合溶剂的超额黏度。用Redlich-Kister方程对超额黏度进行了关联;用Andrade方程、UNIFA-VISCO模型以及Grunberg-Nissan模型对黏度进行了关联与预测。结果表明,混合溶剂的黏度随温度升高和均三甲苯含量增加而减小。超额黏度均为负值,且随均三甲苯含量增加呈U形变化,约在均三甲苯摩尔分数为0.3时达到最低。Grunberg-Nissan模型对黏度数据的关联和预测性最好,预测值与实测值的最大和平均相对偏差分别为12.96%和5.74%。