Monodispersed microcapsules enclosing ionic liquid of 1-butyl-3-methylimidazolium hexafluorophosphate

The widespread research of ionic liquids is mainly because of their unique characteristics, which allow the possibility for more efficient reactions and separations in chemical processes. To achieve a successful commercial status, several problems of ionic liquids should be solved, including loss of ionic liquids and high viscosity that effects on fluid flow and mass transfer. In this study, hollow polysulfone microcapsules filled with ionic liquid of 1-butyl-3-methylimidazolium hexafluorophosphate [BMIM]PF6 were prepared via a two-stage microfluidic approach. The results of the preparation showed that [BMIM]PF6 was successfully encapsulated with polysulfone, as an encapsulation capacity of 30.8% was achieved. Smaller microcapsules were produced with smaller size of nozzle, lower droplet phase flow rate or higher continuous phase flow rate. The microcapsules had excellent monodispersity and spherical morphology with extremely narrow size distribution. Besides, they had good stability of ionic liquid immobilization. The microfluidic approach has been proved successful to fabricate microcapsules, with advantages of extremely narrow size distribution, easy-controlled operating conditions to obtain different size of microcapsules, possibility for on line observation of preparation process.     

纤维二糖在离子液体1-丁基-3-甲基咪唑氯盐中的结构动力学特性

开展分子动力学模拟探索不同压力条件下纤维素的基本结构单元--纤维二糖在离子液体1-丁基-3-甲基咪唑氯盐（[C₄mim]Cl）中的结构动力学特征。研究结果表明,高压环境使二糖分子内氢键网络结构瓦解,二糖与阴阳离子间相互作用增强,形成溶质-溶剂间氢键。借助空间分布函数得到常压及高压环境下二糖分子周围溶剂层分布特征,并通过径向分布函数定量考察了纤维二糖/离子液体体系分子间与分子内的氢键特征,为在化学键水平上认识纤维素在离子液体中溶解机制提供必要的理论基础。     

Physical and electrochemical properties of 1-butyl-3-methylimidazolium bromide, 1-butyl-3-methylimidazolium iodide,and 1-butyl-3-methylimidazolium tetrafluoroborate

The density, viscosity, refractive index, heat capacity, heat of dilution, ionic conductivity, and electrochemical stability of 1-butyl-3-methylimidazolium bromide ([bmim][Br]), 1-butyl-3-methylimidazolium iodide ([bmim][I]), and 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim][BF₄]) were measured at room temperature or over a temperature range of 293.2 to 323.2 K. The density and refractive index values of [bmim][I] appeared to be the highest among three ionic liquids (ILs). However, the experimental viscosity values of [bmim][Br] were higher than those of [bmim][BF₄], while the heat capacities and heats of dilution of [bmim][BF₄] were higher than those of [bmim][Br]. The cyclic voltammogram of [bmim][br] and [bmim][BF₄] indicated electrochemical windows in the stability range from 2.7 V of [bmim][[Br] to 4.7 V of [bmim][BF₄].     

微波辐射下一步法合成1-丁基-3-甲基咪唑六氟磷酸离子液体

采用微波辐射法一步合成1-丁基-3-甲基咪唑六氟磷酸([Bmim]PF6)离子液体,产物结构经过IR和1H NMR验证。通过考察各种影响因素对产物的影响得出最佳的反应条件:n(溴代正丁烷)∶n(1-甲基咪唑)∶n(六氟磷酸钾)=1.1∶1∶1.6(摩尔比),70℃以及250 W的微波功率下照射15 min,收率可达到92.7%。     

[Bmim]BF4离子液体在甲醇中的体积和黏度性质

在298.15 K和常压下,测定了1-丁基-3-甲基咪唑四氟硼酸([Bmim]BF4)离子液体+甲醇体系的密度和黏度。由密度计算了体系的表观摩尔体积,并采用Redlich-Mayer方程关联了体系的表观摩尔体积与组成的关系,得到了[Bmim]BF4在甲醇中的标准偏摩尔体积。由Jones-Dole方程对体系的黏度随组成的变化进行了拟合,获得了[Bmim]BF4在甲醇中的黏度B系数。结果表明:[Bmim]BF4+甲醇体系的表观摩尔体积和黏度均随[Bmim]BF4浓度的增加而增加,[Bmim]BF4在甲醇中的标准偏摩尔体积和黏度B系数分别为155.72×10-6m3/mol和0.282 9。     

纤维素在离子液体1-丁基-3-甲基-咪唑乙酸盐中的溶解性能

研究了纤维素在离子液体1-丁基-3-甲基-咪唑乙酸盐([BMIM] CH3COO)中的溶解性能.结果表明,[ BMIM] CH3COO对天然纤维素有较好的溶解能力,再生得到纤维素膜;随着溶解温度的升高,溶解时间大大缩短.采用红外光谱(FT-IR)、热质量损失分析(TGA)、X-射线衍射(XRD)等对再生前后纤维素进行了...     

Electropolymerization of 1,2-methylenedioxybenzene in 1-butyl-3-methylimidazolium hexafluorophosphate room temperature ionic liquid

The electrochemical polymerization of 1,2-methylenedioxybenzene (MDOB) in a room temperature ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate (BmimPF₆) has been investigated. Its polymer poly(1,2-methylenedioxybenzene) (PMDOB) showed good redox activity and stability even in concentrated sulfuric acid. IR and ¹H NMR spectra confirmed that the polymerization occurred at the C₄ and C₅ positions on the benzene ring of MDOB, resulting in the main backbone of PMDOB similar to polyacetylene. In contrast to acetonitrile containing 0.1 mol/L Bu₄NBF₄, BmimPF₆ serves as both the growth medium and an electrolyte. Hence, enhanced electrochemical stability of PMDOB can be easily obtained on repetitive redox cycling. As-formed PMDOB represented good electrochromic properties from green grass to opalescent between doped and dedoped states. Scanning electron microscopic results demonstrated that smooth and compact PMDOB films composed of ordered nanostructures were obtained, implying their possible utilizations in ion-sieving films, ion-selective, and matrices for catalyst particles.     

室温离子液体1-丁基-3-甲基咪唑六氟磷酸盐的合成研究

由1-甲基咪唑和溴代正丁烷合成了中间体溴化1-丁基-3-甲基咪唑,讨论了温度和反应自身放热对此步反应的影响。中间体再经过阴离子交换,得到了标题化合物,收率为92％。产物的结构经IR和^1HNMR确认。     

Electrochemical aspects of black chromium electrodeposition from 1-butyl-3-methylimidazolium tetrafluoroborate ionic liquid

The electrochemical behaviour of trivalent chromium (Cr³⁺) in 1-butyl-3-methylimidazolium tetrafluoroborate [BMIm][BF₄] ionic liquid solutions was studied by cyclic voltammetry and chronoamperometry. The reduction of Cr³⁺ occurs in two steps, Cr³⁺ to Cr²⁺ and Cr²⁺ to Cr⁰, respectively. The first step is quasi-reversible with a diffusion coefficient of Cr³⁺ in solution of 3.13 × 10⁻⁸ cm² s⁻¹ at 303 K and 25.8 × 10⁻⁸ cm² s⁻¹ at 358 K, estimated from cyclic voltammetry data.Black chromium films were electrodeposited on copper, stainless steel and carbon steel substrates at a constant potential of −1.5 V vs Pt quasi-reference electrode. The films consist of aggregates of nanosized particles. The coatings in the as-deposited condition present an amorphous structure but after annealing for 4 h, a nanocrystalline Cr₂O₃ phase is formed, with an average crystallite size of 17 nm.     

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-甲基咪唑为原料,正丁基溴为烷基化试剂,合成中间体[Bmim]Br,然后与醇钠溶液及氟硼酸反应,制备[Bmim]BF4。结果表明,反应温度80℃,反应24 h,中间体产率为83.7%;目标离子液体的转化率为98.6%。差式扫描量热(DSC)显示,离子液体具有较低的熔点。     

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。     

Anodic behavior of gold in 1-butyl-3-methylimidazolium methanesulfonate ionic liquid with chloride anion

The anodic behavior of gold has been investigated in presence of chloride and/or water in 1-butyl-3-methylimidazolium methanesulfonate (BMI CH₃SO₃) ionic liquid (IL). The cyclic voltammetry (CVs) in presence of chloride ions shows two waves attributed to the oxidation of the gold electrode which occurs under two steps: the first one is attributed to the electrochemical dissolution of gold into to gold(I), while the second one is attributed to an overlap of the chloride oxidation step as well as the oxidation of Au(I) to Au(III). Furthermore the determination of water and chloride content in IL allowed observing that the passive layer induced by water could be removed under chloride. Thanks to those results we were able to clarify the conditions of gold recovering in this kind of electrolyte.     

Electrochemical behavior of rhodium(III) in 1-butyl-3-methylimidazolium chloride ionic liquid

Electrochemical behavior of rhodium(III) chloride in 1-butyl-3-methylimidazolium chloride was investigated by various electrochemical transient techniques at glassy carbon working electrode at different temperatures (343-373 K). Cyclic voltammogram of rhodium(III) in bmimCl consisted of a surge in reduction current occurring at a potential of −0.48 V (vs. Pd) is due to the reduction of Rh(III) to metallic rhodium and a very small oxidation wave occurring at −0.1 V. Increase of scan rate increases the peak current and remarkably shifts the cathodic peak potential () in negative direction indicating the irreversibility of electroreduction of rhodium(III). The diffusion coefficient of rhodium(III) in bmimCl (∼10⁻⁹ cm²/s) was determined and the energy of activation (∼25 kJ/mol) was deduced from cyclic voltammograms at various temperatures. The cathodic (τ_r) and anodic (τ_o) transition times were measured from chronopotential transients and the ratio τ_o/τ_r was found to be 1:7. Electrowinning of rhodium from bmimCl medium results in a deposition of metallic rhodium with lower (20-25%) Faradaic efficiency. A separation factor of rhodium from co-existing noble metal fission product palladium in bmimCl was determined during electrodeposition.     

Determination of cost-effective operating condition for CO2 capturing using 1-butyl-3-methylimidazolium tetrafluoroborate ionic liquid

1-Butyl-3-methylimidazolium tetrafluoroborate ([BMIM][BF4]) ionic liquid (IL) is considered for CO₂ capturing in a typical absorption/stripper process. The use of ionic liquids is considered to be cost-effective because it requires less energy for solvent recovery compared to other conventional processes. A mathematical model was developed for the process based on Peng-Robinson (PR) equation of state (EoS). The model was validated with experimental data for CO₂ solubility in [BMIM][BF4]. The model is utilized to study the sorbent effect and energy demand for selected operating pressure at specific CO₂ capturing rates. The energy demand is expressed by the vapor-liquid equilibrium temperature necessary to remove the captured CO₂ from the spent solvent in the regeneration step. It is found that low recovery temperature can be achieved at specific pressure combination for the absorber/stripper units. In fact, the temperature requirement is less than that required by the typical monoethanolamine (MEA) solvent. The effect of the CO₂ loading in the sorbent stream on the process performance is also examined.     

Synthesis of phosphinic acid resin using acidic 1-butyl-3-methylimidazolium chloroaluminate ionic liquid as catalyst

The resin is functionalized by the introduction of phosphinic acid moieties by Friedel–Crafts phosphination reaction using acidic 1-butyl-3-methylimidazolium chloroaluminate ionic liquid as catalyst. The phosphorous and hydroxyl capacities of the resin are compared with those obtained by using conventional aluminium chloride catalysis. Extraction of uranium(VI) from nitric acid medium by the resins has been studied, and it was found that the distribution coefficient (K_d, mL/g) of uranium(VI) initially decreases with the increase in the concentration of nitric acid, and reaches a minimum value at 1.5 M in nitric acid followed by the increase in K_d values. A maximum distribution coefficient has been obtained when the concentration of nitric acid was 4.0–5.0 M. The extraction data have been fitted in to a Langmuir adsorption model for obtaining the apparent experimental capacity.     

Surface tension and viscosity of 1-butyl-3-methylimidazolium iodide and 1-butyl-3-methylimidazolium tetrafluoroborate, and solubility of lithium bromide+1-butyl-3-methylimidazolium bromide in water

The surface tension and viscosity of 1-butyl-3-methylimidazolium iodide ([bmim][I]) and 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim][BF₄]) were measured over a temperature range of 298. 15 to 323.15 K. It was found that both the viscosity and surface tension decrease with increasing temperature and that the surface tension and viscosity values of [bmim][I] were higher than those of [bmim][BF₄]. Additionally, the solubility of lithium bromide (2)+1-butyl-3-methylimidazolium bromide ([bmim][Br]) (3) in water (1) was measured at three different mass ratios (w₂/w₃=4 and 7, w₃=0) by using a visual polythermal method. The solubility of the suggested systems was better than that of lithium bromide in water.     

乙腈+水+离子液体等压汽液平衡测定与计算

采用改进的Ellis平衡蒸馏仪测定了乙腈+水+1-乙基-3-甲基咪唑磷酸二乙酯盐([EMIM][DEP])、乙腈+水+{1-乙基-3-甲基咪唑醋酸盐([EMIM][OAC])+[EMIM][DEP]}常压(101.3 kPa)等压汽液平衡(VLE)数据。实验结果表明，备选离子液体可促进水+乙腈混合物的分离并消除其共沸点。借助NRTL模型成功关联了含离子液体的三元和四元VLE实验数据，获得了乙腈-[EMIM][DEP]、水-[EMIM][DEP]和[EMIM][OAC]-[EMIM][DEP]二元交互作用参数。应用COSMO-SAC预测了实验VLE，结果令人满意。量化计算表明可与水形成强相互作用的离子液体更易促进乙腈与水的分离。     

离子液体1-乙基-3-甲基咪唑醋酸盐对酿酒酵母AY93161的毒性及其酒精发酵过程的影响

为了考察离子液体在由木质纤维原料制备可发酵糖中的残留对后续酒精发酵过程的影响,对离子液体1-乙基-3-甲基咪唑醋酸盐([Emim]Ac)对酿酒酵母AY93161的毒性及其酒精发酵过程的影响进行研究。通过亚甲基蓝染色,利用OLYMPUS CX41显微镜观察不同[Emim]Ac浓度下对数生长期酵母细胞的形态结构,出芽情况及代谢活性,发现在[Emim]Ac浓度高于5 g·L^-1时,酵母细胞的形态结构会发生变化,在[Emim]Ac浓度高于0.1 g·L^-1时,随着[Emim]Ac浓度的增加,酵母的出芽速率及代谢活性降低。通过平板培养和液体悬浮培养测得[Emim]Ac对酵母的半有效浓度EC50和半抑制浓度IC50分别为4.45、7.70 g·L^-1。通过测定不同[Emim]Ac浓度下酵母酒精发酵的过程数据,发现在[Emim]Ac浓度低于0.1 g·L^-1时,对酵母酒精发酵过程几乎无影响,在[Emim]Ac浓度高于0.1 g·L^-1时,对酵母酒精发酵有抑制作用,[Emim]Ac对酵母酒精发酵的抑制作用主要是由其对菌体生长的抑制所致。     

Vapor pressure measurement and correlation of acetonitrile+1-butyl-3-methylimidazolium chloride,+1-butyl-3-methylimidazolium tetrafluoroborate,and+1-hexyl-3-methylimidazolium chloride

Vapor pressures were measured for acetonitrile+1-butyl-3-methylimidazolium chloride ([C4mim][Cl]),+1-butyl-3-methylimidazolium tetrafluoroborate ([C4mim][BF4]) and+1-hexyl-3-methylimidazolium chloride ...     

乙腈+[C4mim][Cl]、乙腈+[C4mim][BF4]、乙腈+[C6mim][Cl]的气液平衡测定与关联（英文）

Vapor pressures were measured for acetonitrile+1-butyl-3-methylimidazolium chloride ([C4mim][Cl]),+1-butyl-3-methylimidazolium tetrafluoroborate ([C4mim][BF4]) and+1-hexyl-3-methylimidazolium chloride ([C6mim][Cl]) at temperatures of 313 to 353 K by a quasi-static method. The experimental data for the binary sys-tems were correlated by the non-random two liquid (NRTL) equation with an average absolute relative deviation (AARD) of within 1.84%. The results indicate that the three ionic liquids (ILs) can result in a negative deviation from the Raoult's law for the binary solutions containing acetonitrile, and the affinity between ILs and acetonitrile mole-cules fol ows the order [C4mim][BF4]+acetonitrile N [C4mim][Cl]+acetonitrile N [C6mim][Cl]+acetonitrile.