离子液体[BMIM]PF_6中铬的电沉积行为

以一氯丁烷、N-甲基咪唑和KPF6为原料,合成了1-丁基-3-甲基咪唑六氟磷酸盐离子液体([BMIM]PF6),用红外光谱(IR)对产物进行了结构分析.用循环伏安法测试该离子液体在85℃下的电化学窗口为4.7 V.考察了[BMIM]PF6-Cr(Ⅲ)电解液的电化学行为,结果表明,在85℃下Cr(Ⅲ)的还原过程是受扩散控制的一步还原不可逆过程,Cr(Ⅲ)的传递系数α=0.023,阴极扩散系数D0=1.142×10-6cm2/s.在85℃和-1.5 V条件下,用恒电势法在铜片上电沉积Cr(Ⅲ),并通过扫描电子显微镜(SEM)观察了铜片上镀层的表面结构,发现该镀层呈颗粒状,且颗粒的体积随沉积时间的延长而增大.X射线能量色散谱(EDS)和X射线粉末衍射(XRD)测试结果表明,该镀层为无定形的金属铬.     

[C_4mim][PF_6]和[C_4mim][NTf_2]离子液体辐射诱导的相行为及荧光行为变化

离子液体因其低挥发性,高热稳定性及优良的萃取性能被认为是萃取分离放射性核素的新一代绿色溶剂,而研究离子液体本身的辐射效应是其实际应用的重要前提.本文以~(60)Co为辐射源,系统研究了γ辐照对两种常见的憎水性咪唑离子液体1-丁基-3-甲基咪唑六氟磷酸盐([C_4mim][PF_6])和1-丁基-3-甲基咪唑三氟甲基磺酰胺酸盐([C_4mim][NTf_2])的相行为及荧光行为的影响.在相行为方面,γ辐照使离子液体的结晶驰豫时间增加,导致其低温结晶延迟.在荧光行为方面,γ辐照后离子液体的荧光光谱保持原有的"红边效应(red edge effect)",但随吸收剂量增加,光谱整体发生红移(最大移动幅度达150 nm).并且这种"红边效应"在辐照后离子液体的乙腈稀释剂中仍然存在,且随稀释倍数增加光谱整体发生蓝移.[C_4mim][PF_6]和[C_4mim][NTf_2]离子液体辐照后的这种相行为及荧光行为的变化可归因于辐照对其阴阳离子空间相关性(缔合行为)的影响.     

离子液体[bmim]PTSA的微波合成

近年来,随着绿色化学的兴起,离子液体作为一种新型的绿色溶剂已成为国内外科研工作者的研究热点之一.离子液体是由有机阳离子和无机阴离子组成的盐,可以根据需要控制阴阳离子的组成和结构,设计合成出不同特性的离子液体[1].     

RAFT法合成两亲性嵌段共聚物PSt-b-PAA-b-PSt及其在离子液体[BMIM][PF_6]中的自组装

用三硫代碳酸二(α,α′-二甲基-α-乙酸)酯(BDATC)作为链转移剂,苯乙烯St作为第一单体,通过可逆加成-断裂链转移聚合(RAFT)方法合成出大分子链转移剂PSt-CTA,以丙烯酸AA作为第二共聚单体合成出3个不同嵌段比的两亲性嵌段共聚物聚苯乙烯-b-聚丙烯酸-b-聚苯乙烯(PSt-b-PAA-b-PSt).通过傅里叶变换红外光谱(FTIR)和核磁共振氢谱(1H-NMR)确定了PSt-b-PAA-b-PSt结构,使用凝胶渗透色谱(GPC)测定了大分子引发剂PSt-CTA和嵌段共聚物PSt-b-PAA-b-PSt的分子量及分子量分布.将这3个不同嵌段比的两亲性嵌段共聚物在离子液体1-丁基-3-甲基咪唑六氟磷酸盐[BMIM][PF6]中进行自组装,用透射电子显微镜(TEM)观察聚合物在离子液体中自组装结构.研究发现,当PSt的链段长度固定时,胶束的自组装形态主要依赖于PAA链的长度.当PAA链段较长时,胶束呈球形;PAA链段变得较短时,胶束的形态则由球形转变为核壳结构,并且胶束形态在25℃至100℃之间不受温度影响.     

离子液体[bmim][PF6]与[moemim][PF6]结构微不均匀性以及微粘度的光谱探测

室温离子液体由于其极低的蒸汽压、比较好的热稳定性和化学稳定性、良好的分子结构与性能的可设计性等优点,作为一种新型的环境友好溶剂在很多领域有着广泛的应用.对于离子液体的微观结构和微观性能的研究是设计新型离子液体以及扩展离子液体应用的关键.本文通过荧光探针分子香豆素153(C153)的转动动力学和对微观环境敏感的荧光探针分子1, 3-二(1-芘基)丙烷(BPP)的稳态荧光光谱,探测和表征了烷基取代的离子液体1-丁基-3-甲基咪唑六氟磷酸盐([bmim][PF₆])和与其具有相似结构的醚键官能化的离子液体1-甲氧基乙基-3-甲基咪唑六氟磷酸盐([moemim][PF₆])的微观结构和微粘度. C153探针分子在离子液体[bmim][PF₆]中的转动过程具有快、慢两个组分表明离子液体[bmim][PF₆]内部存在松散和紧密的两种结构微区;而C153探针分子在离子液体[moemim][PF₆]中的转动动力学只存在一种过程,说明醚键的引入使得[moemim][PF₆]内部趋于一种类型的微环境.通过C153探针分子的转动时间研究发现,醚键官能化的离子液体[moemim][PF₆]的微粘度小于烷基链取代的离子液体[bmim][PF₆],同时通过BPP探针分子的二聚体激基复合物(excimer)与单体(monomer)荧光发射强度的比值(I_E/I_M)研究也证明这一结果.醚键的引入使得离子液体[moemim][PF₆]相对于离子液体[bmim][PF₆],侧链的极性更大、柔顺性更好,同时醚键有可能作为氢键的受体与阳离子形成氢键从而削弱离子液体中阴、阳离子间的相互作用,使得离子液体[moemim][PF₆]的微观环境比离子液体[bmim][PF₆]更为均一,同时具有更小的微粘度.     

萘环荧光离子液体合成、表征及光谱性能研究

以1-氯甲基萘和N-烷基咪唑为原料,四氢呋喃为溶剂,合成了5个具有荧光的新型离子液体.采用红外光谱(FT-IR)、核磁共振氢谱(1H NMR)、碳谱(13C NMR)等测试技术对产物进行了结构表征.并对其紫外光谱、荧光光谱等光谱性质进行了初步的研究.实验结果表明咪唑离子液体1,2二甲基-4-甲基萘咪唑氯化盐较咪唑离离子...     

离子液体[MBPy]Tf_2N的光谱特征及荧光法检测

为满足疏水性离子液体N-甲基-N-丁基吡咯烷双三氟甲烷磺酰亚胺盐([MBPy]Tf2N)在甘草酸生物催化体系中分析检测的需要,研究了[MBPy]Tf2N的光谱特征,并考察了溶剂、醇-水混合溶剂和p H值对[MBPy]Tf2N荧光特性的影响,建立了生物催化体系中[MBPy]Tf2N的荧光光谱检测方法.研究结果表明,[MBPy]Tf2N在186 nm处有1个最大吸收峰,常规紫外检测法不适于对其进行检测;[MBPy]Tf2N荧光光谱最大激发波长为228 nm,发射波长为340 nm,且其耐光褪色性良好,在水溶液中荧光量子产率为0.067,在醇-水混合溶剂中其荧光强度有增大趋势,在碱性介质中其荧光强度受影响较大;荧光光谱法检测[MBPy]Tf2N的检出限(S/N=3)为1.00μg/m L,标准曲线在5.00~1.25×103μg/m L浓度范围内线性关系良好(R2=0.9999),生物反应液中加标回收率为97.4%~107.4%(相对标准偏差RSD=4.6%).     

醚基功能化离子液体[MOEMIm]Cl和[EOEMIm]Cl热力学性质

通过核磁共振氢谱,核磁共振碳谱,元素分析和热重分析对醚基功能化的离子液体[MOEMIm]Cl和[EOEMIm]Cl进行了表征。在温度范围T=288.15–328.15 K内,测定了离子液体[MOEMIm]Cl和[EOEMIm]Cl的密度(ρ)、表面张力(γ)和折光率(nD)。根据这些实验数据,讨论并计算了离子液体[MOEMIm]Cl和[EOEMIm]Cl的体积性质。计算出离子液体[MOEMIm]Cl和[EOEMIm]Cl的摩尔表面吉布斯自由能(gs)、摩尔表面熵(s)、摩尔表面焓(h)、摩尔极化度(Rm)和摩尔极化率(αp),h均近似为一个常数说明这两种离子液体从内部到表面的过程是一个等库仑过程,同时这两种离子液体的Rm和αp均与温度无关。本文还用摩尔表面Gibbs自由能改进Lorentz-Lorenz方程并预测离子液体表面张力,预测值与实验值高度相关。     

离子液体[Bmim]PF_6溶剂浮选分离富集-光度法测定环境中痕量四环素类抗生素的研究

建立了离子液体溶剂浮选四环素类(TCs)抗生素的新方法。以1-丁基-3-甲基咪唑六氟磷酸盐([Bmim]PF6)和乙酸乙酯(EA)的混合溶剂(V/V=1)为浮选剂,以Al(Ⅲ)为捕集剂,在pH=6.7条件下,分离富集环境水样中四环素(TC)、土霉素(OTC)、金霉素(CTC)三种四环素类抗生素,并用紫外-可见分光光度法测定总含量。方法线性范围为0.2~10.3μg.mL-1,表观摩尔吸光系数3ε80=3.8×105L.mol-1.cm-1,加标回收率达到94.5%~102.2%,相对标准偏差RSD3.76%(n=5)。该方法适合于环境水样中痕量TC、OTC、CTC抗生素总含量的分离分析。     

离子液体的绿色合成及环境性质

针对离子液体的绿色合成及应用过程中的环境性质,对离子液体常规合成的改进、无溶剂的微波和超声辅助合成等方面的研究进展进行了总结,对离子液体在生物体内的累积程度、离子液体的毒性和降解性等方面的研究进行了介绍。     

Nonaqueous microemulsion-containing ionic liquid [bmim][PF6] as polar microenvironment

The phase behavior of toluene/Triton X-100 (TX-100)/1-butyl-3-methylimidazolium hexafluorophosphate([bmim][PF6]) was studied. It was demonstrated that the single-phase microemulsion area covered about 75% of the phase diagram at 25 °C. Electrical conductivities of the system with different w ([bmim][PF6]-to-TX-100 molar ratio) values were determined, and the results were used to locate the sub-regions of the single-phase microemulsion. The results showed that a transform from [bmim][PF6]-in-oil ([bmim][PF6]/O) microstructure via a bicontinuous region to an oil-in-[bmim][PF6] (O/[bmim][PF6]) microstructure occurred with the increase of Φ (weight fraction of TX-100 and [bmim][PF6] in the system). The aggregate size of the reverse microemulsions of [bmim][PF6]/O was determined using small-angle X-ray scattering. The results showed that the size of the reverse microemulsions depended markedly on the w values.     

Gels of ionic liquid [C4mim]PF6 formed by self-assembly of gelators and their electrochemical properties

Three types of gelators, bis(4-octanoylaminophenyl) ether (BODE), bis(4-octanoylaminophenyl) methane (BODM) and 2,4′-bis(octanureido) toluene (BOUT) were utilized as gelators for the gelation of ionic liquid 1-butyl-3-menthyl-imidazolium hexafluorophosphate ([C₄mim]PF₆). The mean minimum gelator concentrations (MGCs) for the [C₄mim]PF₆ were found to be less than 2 wt%. The polarized optical microscopy image of [C₄mim]PF₆ gels reveals the formation of spherical crystallites resulting from the fibrillar aggregates of the gelators. The cyclic voltammograms of the [C₄mim]PF₆ gels indicate a good electrochemical stability over the range from ?3.0 to 3.0 V. The impedance spectra of the [C₄mim]PF₆ gels show good linear relationships between ion conductivity and temperature, indicating that the temperature dependence of the conductivity follows the classical Arrhenius equation.     

阳离子光引发剂芳茂铁六氟磷酸盐的制备

以二茂铁为原料制备了3种阳离子光引发剂芳茂铁六氟磷酸盐.考察了反应温度、反应时间和催化剂用量等因素对反应的影响.对产物进行了IR和UV光谱分析.     

Removal of 2,4-dichlorophenol using ionic liquid [BMIM]+[PF6]- encapsulated PVDF membrane

2,4-Dichlorophenol (2,4-DCP) is one of the toxic chlorophenol compounds found in aquatic environments. Chlorophenols are priority pollutants, due to their high toxicity, mutagenicity and carcinogenicity. In this study, experiments were carried out for the removal of 2,4-Dichlorophenol (Cl₂C₆H₃OH) from aqueous solution using commercial grade PVDF membrane immobilised with 1-Butyl-3-methyl imidazolium hexafluorophosphate [BMIM]⁺[PF6]^- ionic liquid. Scanning Electron Microscopy (SEM) and Fourier Transform Infrared Spectroscopy (FT-IR) used to identify and to confirm the surface morphology, functional groups and operational stability of Ionic Liquid [BMIM]⁺[PF₆]^- encapsulated PVDF membrane. The effect of various factors such as feed phase pH, initial 2,4-DCP concentration, operation time and stirring speed along with different stripping agents such as NaOH, KOH and NH₄OH on the removal of chlorophenols has been investigated. The maximum permeation rate of 85.52% was achieved over an experimental run of 24 at pH 4 with a strip flux of 8.18323 × 10^?09 mol m^?2s^?1 in 0.1 M NaOH strip phase.     

Ordering layers of [bmim][PF6] ionic liquid on graphite surfaces: molecular dynamics simulation

Microscopic structures of room temperature ionic liquid (IL) [bmim][PF6] on hydrophobic graphite surfaces have been studied in detail by molecular dynamics simulation. It is clearly shown that both the mass and electron densities of the surface adsorbed ionic liquid are oscillatory, and the first peak adjacent to the graphite surface is considerably higher than others, corresponding to a solidlike IL bottom layer of 6 angstroms thick. Three IL layers are indicated between the graphite surface and the inner bulk IL liquid. The individually simulated properties of single-, double-, and triple-IL layers on the graphite surface are very similar to those of the layers between the graphite surface and the bulk liquid, indicating an insignificant effect of vapor-IL interface on the ordered IL layers. The simulation also indicates that the imidazolium ring and butyl tail of the cation (bmim+) of the IL bottom layer lie flat on the graphite surface.     

Vapor-liquid-liquid equilibria of pentafluoroethane and ionic liquid [bmim][PF6] mixtures studied with the volumetric method

In this article, we investigate vapor-liquid-liquid equilibria (VLLE) of binary systems using a simple volumetric method. Being different from the usual cloud-point method for the determination of liquid-liquid separation boundaries, the present volumetric method is able to determine the direct VLLE properties, such as equilibrium compositions, as well as molar volumes of the two liquid phases, by measuring only weights and volumes of liquid samples. The theory behind this method is described, and detailed error analyses for our simple apparatus are discussed by using well-established systems in the literature: water + 2-butanol and 1-butanol + 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF(6)]). Then, results for mixtures of [bmim][PF(6)] and pentafluoroethane (R-125) are provided, as well as those of the test systems above. As predicted in our earlier work, this binary system shows liquid-liquid separations in the R-125-rich side solutions with a lower critical solution temperature. In addition, we have found very large negative excess molar volumes in this system.     

Refined potential model for atomistic simulations of ionic liquid [bmim][PF6

Refined parameters of an atomistic interaction potential model for the room temperature ionic liquid 1-n-butyl,3-methylimidazolium hexafluorophosphate are presented. Classical molecular dynamics simulations have been carried out to validate this fully flexible all-atom model. It predicts the density of the liquid at different temperatures between 300 and 500 K within 1.4% of the experimental value. Intermolecular radial distribution functions and the spatial distribution functions obtained from the new model are in close agreement with ab initio simulations. The calculated diffusion coefficients of ions and the surface tension of the liquid agree well with experiment.     

离子液体[Emim]PF6-邻菲咯琳萃取回收废旧电池中镐、镍离子的研究

研究了疏水性离子液体[Emim] PF_6-邻菲咯琳萃取体系对废旧镍镉电池中镉、镍离子的萃取性能,考察了振荡时间、温度、平衡水相酸度和萃取剂用量时萃取性能的影响.在水相pH值为5.91、温度为80℃时,4.0mL4g/L的邻菲咯琳与3.0mL离子液[Emim] PF_6组成的萃取体系时废旧电池液中镉、镍离子萃取效果良好.同时研究了废旧离子液在不同时间及酸度下的反萃效果,在浓度为1.0mol/L的盐酸介质中反萃1h,镉、镍离子能较好地被反萃.