咪唑盐离子液体的微波合成、表征及性质研究

通过微波辐射,在无溶剂的状态下以N-甲基咪唑为原料合成了4种氯化1-烷基-3-甲基咪唑盐([Bmim]Cl、[Omim]Cl、[C_12mim]Cl、[C_16mim]Cl)离子液体,并测定了离子液体的表面张力和吸水性能.     

两种咪唑类离子液体对杉木粉的溶解性能

合成了氯化1-（2-羟乙基）-3-甲基咪唑（［HeMIM］Cl）和氯化1-烯丙基-3-甲基咪唑（［AMIM］Cl）两种离子液体,并用红外和核磁谱图对其结构进行表征。以不同浓度的NaOH对杉木粉进行活化预处理,比较了这两种离子液体对活化后的杉木粉的溶解能力,并用红外光谱和X射线衍射分析了溶解前和溶解后杉木粉的化学结构与结晶结构的变化。结果表明,两种离子液体对木材中的纤维素表现出一定的溶解能力,且［HeMIM］Cl对杉木粉的溶解能力优于［AMIM］Cl,当选用浓度为25％的NaOH对杉木粉进行活化时,溶解性能最佳,且溶解后再生纤维素的结晶度变低。     

咪唑类离子液体溶解纤维素的研究进展

综述了1-丁基-3-甲基咪唑氯盐、1-烯丙基-3-甲基咪唑氯盐、1-(2-羟乙基)-3-甲基咪唑氯盐等咪唑类离子液体对纤维素的溶解性能,咪唑类离子液体/纤维素溶液的流变性能以及咪唑类离子液体在纤维素纤维及薄膜加工中的应用;咪唑类离子液体均能较好地溶解纤维素,咪唑类离子液体/纤维素溶液均为切力变稀流体;指出选择合适的阴、...     

四种烷基咪唑磷酸酯离子液体的热力学性质

针对烷基咪唑磷酸酯离子液体的热物性数据较少的问题,本文在常压下测定了1-乙基-3-甲基咪唑磷酸二氢盐（[EMIM][DHP]）、1-乙基-3-甲基咪唑磷酸二甲酯盐（[EMIM][DMP]）、1-乙基-3-甲基咪唑磷酸二乙酯盐（[EMIM][DEP]）、1-丁基-3-甲基咪唑磷酸二丁酯盐（[BMIM][DBP]）四种烷基咪唑磷酸酯离子液体的密度、黏度（293.15～353.15K）和电导率（293.15～343.15K）,并且测定了四种离子液体的热稳定性。结果表明,离子液体的密度、黏度随温度的升高而减小,而电导率随温度的升高而增大。采用自然对数方程关联四种离子液体的密度,根据实验值计算到了离子液体体积性质;采用VFT方程关联离子液体黏度和电导率,其中密度与电导率的实验值与模型相关系数R2达到0.9999,黏度相关系数R2达到0.99999,实验测定的数据与模型一致;四种离子液体的热稳定性相近,分解温度均在271.9～278.6℃范围内;瓦尔登规则分析表明,四种烷基咪唑磷酸酯离子液体符合Walden规则,而[EMIM][DMP]和[EMIM][DEP]被归类为“good ionic liq...     

离子液体对水润滑丁腈橡胶摩擦性能的影响

考察了由3种咪唑类离子液体改性制得的丁腈橡胶（NBR）的硫化特性、动态力学性能、物理机械性能及水润滑条件下的摩擦系数、摩擦表面形貌和磨损体积,并研究了咪唑类离子液体的作用机制。结果表明,3种咪唑类离子液体均可提高NBR的交联密度和物理机械性能;1-丁基-3-甲基咪唑六氟磷酸盐［（BMim）PF6］能有效减小NBR在去离子水中的体积变化。经咪唑类离子液体改性后,NBR进入混合润滑的线速率由0.180 m/s降至0.045 m/s;添加1-丁基-3-甲基咪唑溴盐［（BMim）Br］和（BMim）PF6的NBR在线速率达到1.800 m/s时均进入弹流动压润滑;3种离子液体均可有效降低边界润滑阶段、混合润滑阶段和弹流动压润滑阶段的摩擦系数,尤其在边界润滑阶段和混合润滑阶段的改善效果显著,其中（BMim）Br和（BMim）PF6改善动摩擦系数效果更好,1-丁基-3-甲基咪唑四氟硼酸盐［（BMim）BF4］和（BMim）PF6改善静摩擦系数和减少体积磨损效果更好。     

3种咪唑类离子液体的物理性质研究

咪唑类离子液体是目前应用最多的离子液体之一,然而有关其物理化学性质的研究较少。为了给离子液体的工业应用提供数据参考,本文合成了3种常用的咪唑类离子液体1-乙基-3-甲基咪唑磷酸二乙酯([Emim]DEP)、1-乙基-3-甲基咪唑醋酸([Emim]Ac)和1-丁基-3-甲基咪唑氯([Bmim]Cl),测定了它们的密度、黏度、玻璃态转化温度(Tg)和酸度离解常数(p Ka),并研究了它们的热稳定性。在3种离子液体中,[Emim]DEP热稳定性最好且黏度较低,具有更广阔的工业应用前景。     

长链烷基咪唑类离子液体型表面活性剂的聚集行为

采用微波辐射法合成了咪唑类离子液体1-烷基-3-甲基咪唑氯盐[C_nMim]Cl (n=12,14,16),测定了[C_nMim]Cl的电导率及表面张力。结果表明,随着烷基链长度的增加,临界胶束浓度(CMC)与最小表面张力(γCMC)减小,[C_(16)Mim]Cl的表面活性最好。胶束化热力学参数(ΔG_(mic)~0、ΔH_(mic)~0、ΔS_(mic)~0)表明,[C_(12)Mim]Cl的胶束化是熵驱动;而对于[C_(14)Mim]Cl与[C_(16)Mim]Cl的胶束化而言,25℃为焓驱动,超过35℃为熵驱动。     

离子液体[BzMim][BF4]催化甲苯与盐酸和聚甲醛的氯甲基化反应

以1-甲基咪唑和氯化苄为原料合成中间体氯化1-苄基-3-甲基咪唑（[BzMim]Cl）,而后与氟硼酸钠交换阴离子合成了一种新的离子液体[BzMim][BF4],并考察了该离子液体催化甲苯与盐酸和聚甲醛的氯甲基化反应的催化活性和选择性。实验结果表明,[BzMim][BF4]能够催化以浓盐酸为原料的氯甲基化反应,目标产物甲基苄基氯的产率与文献报道以离子液体C12mimBr催化干燥氯化氢为原料的相仿;对同为浓盐酸原料的氯甲基化反应,其单氯甲基化选择性远高于文献报道的以离子液体[emim]BF4为催化剂的35%;当[BzMim][BF4]与甲苯的摩尔比为0.3,多聚甲醛（PF）与甲苯的摩尔比为1.3,浓盐酸与甲苯的摩尔比为7.5,80 oC下反应8 h时,目标产物甲基苄基氯的产率达到88.5%,单氯甲基化选择性高于99%。     

多烷基咪唑离子液体的合成及性能比较

以咪唑或1,2-二甲基咪唑和卤代烷为原料,合成了4种多烷基咪唑类离子液体,以及6种1,3-二丁基咪唑和1-丁基-3-乙基咪唑类离子液体,产率较高。产物结构经核磁共振氢谱进行了确认。测定了产物水溶液的pH和不同浓度下的电导率,研究了烷基对离子液体酸性的影响,以及不同阴离子或烷基链长度对电导率的影响。测定了产物的吸湿性,结果表明,多烷基咪唑六氟磷酸盐离子液体具有较低的吸湿性。     

长链烷基咪唑类离子液体型表面活性剂的聚集行为

采用微波辐射法合成了咪唑类离子液体1-烷基-3-甲基咪唑氯盐[C_nMim]Cl (n=12,14,16),测定了[C_nMim]Cl的电导率及表面张力。结果表明,随着烷基链长度的增加,临界胶束浓度(CMC)与最小表面张力(γCMC)减小,[C_(16)Mim]Cl的表面活性最好。胶束化热力学参数(ΔG_(mic)⁰、ΔH_(mic)0、ΔH_(mic)⁰、ΔS_(mic)0、ΔS_(mic)⁰)表明,[C_(12)Mim]Cl的胶束化是熵驱动;而对于[C_(14)Mim]Cl与[C_(16)Mim]Cl的胶束化而言,25℃为焓驱动,超过35℃为熵驱动。     

离子液体在甲醇/硫酸介质中对Q235钢表面的缓蚀性能

探究硫酸存在时Q235钢在甲醇中的腐蚀行为,以及离子液体1-丁基-3-甲基咪唑氯盐（[Bmim]Cl）对金属表面的缓蚀作用。通过静态失重法、电化学测试、扫描电子显微镜来测定[Bmim]Cl对Q235钢的缓蚀性能。并利用量子化学计算和分子动力学模拟分析[Bmim]Cl分子的缓蚀机理。在甲醇中随着硫酸含量的增加碳钢的腐蚀速率增加。含有59.51 ml 0.05 mol·L^-1 H₂SO₄的甲醇溶液作为腐蚀介质时,随着[Bmim]Cl浓度升高,缓蚀效率逐渐增大,当浓度为0.6 mol·L^-1时,缓蚀效率达到最佳值,为90.63%,且[Bmim]Cl是主要控制阳极反应的混合抑制剂,SEM分析表明在含有缓蚀剂溶液中浸泡后的Q235钢表面相对于未加缓蚀剂更加平整。前线轨道分析和Fukui指数都表明,离子液体在碳钢表面的吸附位点分布在咪唑环上,与Fe发生化学吸附。分子动力学模拟结果表明缓蚀剂分子以阳离子[Bmim]⁺平行吸附于金属表面,阴离子Cl^-扩散在溶液中的方式达到缓蚀的效果。理论计算结果与实验结果一致,即[Bmim]Cl在甲醇/硫酸水溶液中对Q235钢具有很好的缓蚀作用,为新型离子液体缓蚀剂研究应用奠定了基础。     

Recovery of the N,N-Dibutylimidazolium Chloride Ionic Liquid from Aqueous Solutions by Electrodialysis Method

Ionic liquids (ILs), named also as liquid salts, are compounds that have unique properties and molecular architecture. ILs are used in various industries; however, due to their toxicity, the ILs’ recovery from the postreaction solutions is also a very important issue. In this paper, the possibility of 1,3-dialkylimidazolium IL, especially the N,N-dibutylimidazolium chloride ([C₄C₄IM]Cl) recovery by using the electrodialysis (ED) method was investigated. The influence of [C₄C₄IM]Cl concentration in diluate solution on the ED efficiency was determined. Moreover, the influence of IL on the ion-exchange membranes’ morphology was examined. The recovery of [C₄C₄IM]Cl, the [C₄C₄IM]Cl flux across membranes, the [C₄C₄IM]Cl concentration degree, the energy consumption, and the current efficiency were determined. The results showed that the ED allows for the [C₄C₄IM]Cl recovery and concentration from dilute solutions. It was found that the [C₄C₄IM]Cl content in the concentrates after ED was above three times higher than in the initial diluate solutions. It was noted that the ED of solutions containing 5–20 g/L [C₄C₄IM]Cl allows for ILs recovery in the range of 73.77–92.45% with current efficiency from 68.66% to 92.99%. The [C₄C₄IM]Cl recovery depended upon the initial [C₄C₄IM]Cl concentration in the working solution. The highest [C₄C₄IM]Cl recovery (92.45%) and ED efficiency (92.99%) were obtained when the [C₄C₄IM]Cl content in the diluate solution was equal 20 g/L. Presented results proved that ED can be an interesting and effective method for the [C₄C₄IM]Cl recovery from the dilute aqueous solutions.     

Effects of 1-Alkyl-(and 1-Benzyl)-2,3-Dimethylimidazolium Ionic Liquids as Additives on the Micellar Behavior of Surfactant SB-12

The micellization and surface-active behavior of zwitterionic surfactant N-dodecyl-N,N-dimethyl-3-ammonio-1-propanesulfonate (SB-12) in aqueous media were investigated in the absence and presence of different alkyl-appended and benzyl-appended ionic liquids (IL) 1-butyl-2,3-dimethylimidazolium chloride [bdmim][Cl], 1-butyl-2,3-dimethylimidazolium bromide [bdmim][Br], 1-hexyl-2,3-dimethylimidazolium bromide [hdmim][Br], and 1-benzyl-2,3-dimethylimidazolium chloride [bzdmim][Cl]. The characteristics of self-organization processes in SB-12 + IL/water systems include critical micelle concentration (cmc), aggregation number (N_agg), micellar size (D), surface, and adsorption parameters. These parameters were determined by the fluorescence and surface tension measurements. In SB-12 solutions, cmc were found to be decreasing to different extents in the presence of all the studied IL than in pure water. The addition of IL [hdmim][Br] decreases the cmc of aqueous SB-12 to rather a low extent. The other three IL show a prominent lowering in cmc of surfactant SB-12 to different magnitude. The maximum lowering in cmc was observed due to addition of benzyl-appended IL [bzdmim][Cl]. The aggregation number of aqueous SB-12 solution obtained in general is higher at high wt.% of added IL. The average micellar size was also found to increase upon addition of IL. Both IL anions and cations interacted with the charged centers present on the zwitterionic surfactant SB-12, which caused a substantial increase in the surface activity.     

Electrical conductivities for four ternary electrolyte aqueous solutions with one or two ionic liquid components at ambient temperatures and pressure

Thiswork provides amethod to explore the transport property of the electrolyte aqueous solutionswith one or two ionic liquids, especially focus on their electrical conductivity. The conductivities were measured for the ternary systems NaCl–[C₆mim][Cl] (1-hexyl-3-methylimidazolium chloride)–H₂O, [C₆mim][BF₄]–[C₆mim][Cl]–H₂O, NaNO₃–[C₆mim][BF₄](1-hexyl-3-methylimidazolium tetrafluoroborate)–H₂O, and [C₄mim][BF₄] (1-butyl-3- methylimidazolium tetrafluoroborate)–[C₆mim][BF₄]–H₂O, and their binary subsystems NaNO₃–H₂O, NaCl–H₂O, [C₆mim][BF₄]–H₂O, [C₆mim][Cl]–H₂O, and [C₄mim][BF₄]–H₂O, respectively. The conductivities of the ternary systems were also determined using generalized Young's rule and semi-ideal solution theory in terms of the data of their binary solutions. The comparison showed that the two simple equations provide good predictions for conductivity of mixed electrolyte solutions and the mixed ionic liquid solutions based on the conductivity of their binary subsystems.     

酸改性膨润土对［BMIM］Cl离子液体的吸附

利用酸改性膨润土对低浓度［BMIM］Cl离子液体水溶液的吸附性能进行研究;考察了吸附温度、吸附时间、溶液pH值等吸附条件对离子液体的吸附率的影响。结果表明;酸改性膨润土对［BMIM］Cl的阳离子具有良好的吸附作用。在中性溶液中;酸改性膨润土对离子液体具有最大的吸附率。酸改性膨润土对离子液体的吸附过程是放热过程且属于Langmuir等温吸附;同时;得到膨润土上离子液体吸附的Langmuir等温方程且相关系数大于0.99。     

Rheological Behavior of Poly(m-phenyleneisophthalamide) in Ionic Liquid

Summary The rheological behavior of poly(m-phenyleneisophthalamide) (PMIA) in 1-n-butyl-3-methylimidazolium chloride ([Bmim]Cl, ionic liquid) has been investigated. The polymer in the concentration range investigated exhibits very different behavior between [Bmim]Cl and DMAc/LiCl solvent. Unlike in DMAc/LiCl solvent, PMIA/[Bmim]Cl solution exhibits maxima in apparent viscosity-concentration plots in the range studied. The complex viscosity-frequency behavior of the PMIA/[Bmim]Cl solutions is similar to that steady-state rheological behavior. The different rheological behavior shows the interaction between macromolecule and IL which leading the supermolecular aggregates in PMIA/[Bmim]Cl solution.     

溴化锂及离子液体水溶液密度、黏度和表面张力测定与计算

常压条件下,实验测定了不同温度（283.15~343.15 K）下吸收制冷/热泵工质对——溴化锂（LiBr）、1-乙基-3-甲基咪唑醋酸盐（[EMIM][OAC]）和1-丁基-3-甲基咪唑硫氰酸盐（[BMIM][SCN]）水溶液的密度、黏度和表面张力,借助线性方程和Vogel-Tammann-Fulcher（VTF）模型,分别成功关联了密度和黏度实验值。研究结果表明：在相同条件下,溴化锂水溶液的密度大于离子液体水溶液的密度,而前者的黏度小于后者;对表面张力,随着溴化锂含量增加,其水溶液的表面张力值增加,而少量离子液体可使水的表面张力快速下降。根据实验黏度和表面张力分别获得了能量势垒和表面熵/焓,表明各水溶液中分子或离子迁移难易程度遵循[EMIM][OAC] > [BMIM][SCN] > LiBr,表面有序性遵循[BMIM][SCN] > [EMIM][OAC] > LiBr。研究结果可为吸收制冷/热泵工质对及低温余热回收系统的设计和计算提供可靠的数据支撑。     

Rheological Behaviors of Polyacrylonitrile/1-Butyl-3-Methylimidazolium Chloride Concentrated Solutions

One of the room temperature ionic liquids (RTILs), 1-butyl-3-methylimidazolium chloride ([BMIM]Cl) was chosen to prepare the concentrated solutions of Polyacrylonitrile (PAN). The rheological behaviors of the solutions were measured with rotational rheometry under different conditions, including temperatures, concentration, and molecular weight of PAN. The solutions exhibited shear-thinning behaviors, similar to that of PAN/DMF solutions. The viscosities decreased with the increasing of shear rates. However, the viscosity decreased sharply at high shear rates when the concentration was up to 16wt%. The dependence of the viscosity on temperature was analyzed through the determination of the apparent activation energy. Unusually, the viscosity of solutions of higher concentration is lower than that of lower concentration. Similarly, the viscosity of low molecular weight PAN was higher than high molecular weight PAN at high shear rates. The dynamic rheological measurement indicates the loss modulus is much higher than storage modulus. The trend of complex viscosity is similar with the result of static rheological measurement. The interaction between PAN and ionic liquid [BMIM]Cl was discussed.     

Micellization behavior of ionic liquid surfactants with two hydrophobic tail chains in aqueous solution

The drop volume method was used to determine the surface tensions of two series of polymerizable ionic liquid surfactants, namely, 1‐acryloyloxypropyl‐3‐alkylimidazolium chloride [APC_nim][Cl] (n = 8, 10, 12) containing two hydrophobic tail chains and 1‐propionyloxypropyl‐3‐alkylimidazolium chloride [PPC_nim][Cl] (n = 8, 10, 12), which showed similar structures with [APC_nim][Cl] (n = 8, 10, 12) at 25°C. The surface properties of the surfactants were also compared. Furthermore, the thermodynamic behavior of [PPC_nim][Cl] (n = 10, 12, 14) micellization in aqueous solution and the enthalpy–entropy compensation phenomenon were studied. The two kinds of surfactants had high surface activity. Double bonds had almost no effect on the surface properties of [APC_nim][Cl]. The micellization of [PPC_nim][Cl] in aqueous solution was spontaneous and entropy‐driven. For the surfactant with specific structure, micellization ability initially increased and then decreased with temperature increase. The entropic contribution to Gibbs free energy change tended to decrease, whereas the enthalpic contribution increased. In addition, the enthalpy–entropy compensation phenomenon occurred during the micellization process. For all [PPC_nim][Cl], the compensation temperature was (314 ± 1) K, which remained unaffected by the surfactant molecular structure. However, when the hydrophobic carbon chain length increased, both micelle formation ability and stability increased. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Separation of methyl linolenate and its analogues by functional mixture of imidazolium based ionic liquid-organic solvent-cuprous salt

Methyl linolenate was separated from its analogues by a new extraction system constructed by solvent,imidazolium based ionic liquids and cuprous salt. Firstly, the effect of ionic liquid on the dissolution of CuCl in acetonitrile, N,N-dimethylformamide(DMF), methanol and water was evaluated by visual observation. [C_4Mim][Cl]can improve the dissolution of CuCl in acetonitrile. Then, for the new system as acetonitrile-ILs-CuCl, extraction equilibrium, distribution ratio and selectivity of methyl linolenate and its analogues were determined by gas chromatography analysis and the mass balance. The extraction time, IL structures and CuCl concentrations were investigated. Distribution ratio decreased slightly, but selectivity increased significantly with the addition of CuCl, [C_4Mim][Cl] or [C_4Vim][NTF_2] into acetonitrile. [C_4Vim][NTF_2] had higher selectivity than [C_4Mim][Cl].But the selectivity of the system combining CuCl with [C_4Vim][NTF_2] was much lower than with [C_4 Mim][Cl].For the CuCl-[C_4Mim][Cl]-acetonitrile, the extraction efficiency was better than CuCl-acetonitrile, increasing Cu~+ concentration effectively improved the separation selectivity when ratio of CuCl/[C_4Mim][Cl] was less than 1. Compared with previous aqueous AgNO_3 extractions, the method of using CuCl is a much cheaper and practical way to enrich unsaturated fatty acid.