1-辛基-3-甲基咪唑离子液体作为可循环溶剂萃取/去除水中二价汞研究

本研究采用1-辛基-3-甲基咪唑离子液体([C₈MIM]PF₆)建立了水中Hg²⁺的循环去除方法. 首先使用[C₈MIM]PF₆萃取水中Hg²⁺, 随后通过甲酸的还原反应, 去除萃取到[C₈MIM]PF₆中的Hg²⁺, 进而实现[C₈MIM]PF₆的回收与循环使用. 本研究优化了萃取与还原去除条件, 考察了最佳条件下[C₈MIM]PF₆的循环使用能力. 结果表明, 50 mL水中加入1 mL[C₈MIM]PF₆同时加入0.2 mL 1-甲基咪唑, 50 ℃、220 r/min震荡2 h, 对Hg²⁺的萃取效率接近100%. 随后在离子液体中加入4 mL, 40%甲酸溶液, 50 ℃下220 r/min震荡30 min, 可以将[C₈MIM]PF₆中60%～70%的Hg²⁺还原去除. 采用这一方式对水中Hg²⁺进行循环萃取, 在9次萃取中,[C₈MIM]PF₆对Hg²⁺的去除效率保持在83%～98%. 因此, 本方法不仅实现[C₈MIM]PF₆对水中Hg²⁺的去除, 同时实现了[C₈MIM]PF₆的回收与循环使用, 避免了[C₈MIM]PF₆过度使用所带来的环境问题.     

新奇二茂铁甲基氮C60衍生物的合成、结构

尽管目前人们对富勒烯[C₆₀]的过渡金属有机物研究较多^[1],但通过氮卡宾方式连接的C₆₀二茂铁衍生物尚未见报道。鉴于对C₆₀反应的浓厚兴趣及二茂铁的广泛应用价值^[2]我们 利用C₆₀的缺电子性^[3]将其与二茂铁甲基氮卡宾进行[1+2]环加成反应,分离并表征了一种具有齿轮式结构的新奇C₆₀二茂铁衍生物(CpFeC₅H₄CH₂N)5C₆₀(l)。     

层级结构BiOBr的离子液体辅助合成及其对苯胺的可见光催化降解

分别以溴代甲基咪唑反应型离子液体[C₄mim]Br、[C₈mim]Br和[C₁₂mim]Br作为溴源和软模板,通过乙二醇溶剂热处理,获得了3种不同形貌结构的溴化氧铋(BiOBr)微粉。 X射线衍射(XRD)、扫描电子显微镜(SEM)和比表面积测定的表征结果证实,产物均属四方晶系,纯度较高,且随着离子液体中阳离子取代基上碳原子数(C_n)的增多,BiOBr晶体沿着(110)晶面择优生长;微米级的BiOBr产物颗粒均是由纳米尺度的花瓣状薄片相互簇集、自组装而形成,呈球心放射状,粒径和表面孔隙均随C_n的增加而减小,但比表面积随之而增大。 可见光降解苯胺的结果表明,3种BiOBr催化剂的催化活性不同,反应280 min时,降解率依次为54.13%、78.67%和95.06%;光生空穴是光降解过程的主要活性物质,羟基自由基所起的作用较小。     

阴离子功能化生物柴油离子液体抗氧化剂[X][C6H5COO]的制备

设计合成了两种阴离子功能化离子液体抗氧化剂（[MI][C₆H₅COO]、[Ch][C₆H₅COO]）,采用核磁共振氢谱、傅里叶红外光谱对其结构进行了表征,并研究了两种离子液体抗氧化剂对小桐子生物柴油抗氧化性、铜片腐蚀性和油溶性能的影响。结果表明,离子液体抗氧化剂可有效提高生物柴油氧化稳定性,在添加量为0.3‰时,[MI][C₆H₅COO]的小桐子生物柴油诱导期提高了238%,超过了中国国家标准（6 h）,[Ch][C₆H₅COO]的小桐子生物柴油诱导期提高了141%,未达到中国国家标准。进一步研究了两种离子液体抗氧化剂的油溶性,油溶性能从大到小的顺序为[MI][C₆H₅COO] > [Ch][C₆H₅COO] > GA（合成离子液体抗氧化剂的原料）。实验表明,合成的两种离子液体抗氧化剂中含有亲油阳离子的[MI][C₆H₅COO]综合性能明显优于含有亲水阳离子的[Ch][C₆H₅COO]。     

表面活性离子液体溴化N-十二烷基异喹啉与非离子表面活性剂Triton X-100在水溶液中的混合胶束

用等温滴定微量热法测定表面活性离子液体溴化N-十二烷基异喹啉([C₁₂iQuin]Br)与非离子表面活性剂Triton X-100混合物在水溶液中的临界胶束浓度。并以¹H核磁共振(NMR)和二维核Overhauser效应增强谱(2D NOESY)研究[C₁₂iQuin]Br与Triton X-100在混合胶束中的作用机理。研究结果显示：混合胶束中,Triton X-100分子的苯环定位于混合胶束的内核,聚氧乙烯链卷曲在异喹啉环周围。本文还应用规则溶液理论和浊点法对比研究了十二烷基三甲基溴化铵(DTAB)-Triton X-100混合胶束体系的相关性质。     

阴离子插层镁铝水滑石结构及相互作用的理论研究

采用密度泛函理论(DFT)计算了MgAl-LDHs层板与无机阴离子(F^-、Cl^-、NO₃^-、CO₃^2-、SO₄^2-)和有机阴离子(水杨酸根离子([HO(C₆H₄)COO]^-)、苯甲酸根离子([(C₆H₅)COO]^-)、对二甲氨基苯甲酸根离子([p-(CH₃)₂N(C₆H₄)COO]^-)、十二烷基磺酸根离子[C₁₂H₂₅SO₃]^-、己烷基磺酸根离子[C₆H₁₃SO₃]^-、丙烷基磺酸根离子[C₃H₇SO₃]^-)间的相互作用,获得稳定超分子几何结构及相互作用能。层板主体与客体间存在较强的超分子作用,包括主客体间静电作用和氢键等。主、客体间相互作用能数值大小顺序为CO₃^2- > SO₄^2- > F^-> Cl^-> NO₃^-;[p-(CH₃)₂N(C₆H₄)COO]^-> [(C₆H₅)COO]^-> [HO(C₆H₄)COO]^-和[C₁₂H₂₅SO₃]^-> [C₆H₁₃SO₃]^- > [C₃H₇SO₃]^-。另外,还采用自然键轨道(NBO)计算和分析了LDHs 层板与阴离子间作用机理,从二阶微扰理论计算得到的稳定化能变化趋势与相互作用能数据基本吻合。     

碳氟醇对阳离子表面活性剂表面活性及胶团反离子结合度的影响

用表面张力及电动势法研究了C₁₀H₂₁N(CH₃)3Br、C₁₂H₂₅N(CH₃)3Br与C₃F₇CH₂OH混合水溶液的表面与胶团性质。结果表明,对于阳离子表面活性剂,C₃F₇CH₂OH的加入一方面增加表面活性,另一方面降低胶团反离子结合度。后者不同于阴离子表面活性剂/C₃F₇CH₂OH混合体系,可归因于C₃F₇CH₂OH略有酸性,因而具备一些类似阴离子表面活性剂的性质。     

室温离子液体对氨基苯磺酸的萃取性能

系统研究了[C₄mim][PF₆], [C₆mim][PF₆], [C₆mim][BF₄]和[C₈mim][BF₄]室温离子液体对间氨基苯磺酸、对氨基苯磺酸稀水溶液的萃取平衡. 实验结果表明: 萃取温度和相体积比的变化对分配比影响不大; 水相pH值对萃取平衡有较大的影响, 氨基苯磺酸在离子液体/水体系中的分配比在pH＝4.2时达到最大值; 水相中CaCl₂或Na₂SO₄的存在能较大幅度地提高氨基苯磺酸的分配比; 离子液体的阴离子的性质对分配比有显著的影响, 阴离子为[BF₄]^－的离子液体对氨基苯磺酸的萃取能力大于阴离子为[PF₆]^－的离子液体; 咪唑环上烷基链的长度也对萃取效果有一定的影响. 在所研究的离子液体中, [C₆mim][BF₄]和[C₈mim][BF₄]对氨基苯磺酸有较好的萃取性能, 且萃取相中的氨基苯磺酸可回收利用, 离子液体也可循环使用.     

新型金属-双二硫杂戊烯(M-BDT)配合物的合成、表征及X射线的指标化

合成了4个新型NiBDT配位化合物,BDT为具有9个S原子的杂戊烯.元素分析、IR谱、UV谱确定这4个新配合物的化学式分别为[(CH₃)₄N]₂[Ni(C₅S₉)₂](1),[(C₂H₅)₄N]₂·[Ni(C₅S₉)₂](2),[(C₄H₉)₄N]₂[Ni(C₅S₉)₂](3),[(C₆H₅)(CH₃)₃N]₂[Ni(C₅S₉)₂](4).采用Ito法对配合物1的X射线粉末图进行了指标化,确定该晶体属单斜晶系,简单晶格,晶胞参数:a=0.680nm,b=0.714nm,c=2.302nm,γ=111.4°,Z=2.     

多功能离子液体分散液液微萃取结合高效液相色谱法检测人尿中5种邻苯二甲酸酯代谢物

将多功能离子液体与分散液液微萃取（DLLME）技术相结合，建立了测定尿液中5种邻苯二甲酸酯类（PAEs）物质代谢产物的高灵敏度新方法。对影响DLLME效率的各单因素进行了优化，包括萃取剂的种类及体积、分散剂的种类及体积、萃取温度、超声时间、冷却时间、离心时间和盐效应等条件，经过严格的优化，最佳的萃取条件分别为：萃取剂[C₈MIM]PF₆]35 μL，分散剂[BSO₃HMIm]OTf]30 μL和[C₄MIM]BF₆]120 μL，萃取温度为35℃，超声时间5 min，冷却时间5 min，离心时间5 min，盐析剂NH₄PF₆ 0.1 g。在最佳的萃取条件下，5种PAEs代谢物在0.5~1000 μg/L范围内具有良好的线性关系，决定系数（R²）均大于0.9955，方法检出限为0.16~0.19 μg/L，尿液中添加低中高水平（5、20、100 μg/L）的PAEs代谢物，其回收率为92.9%~105.0%，日内精密度及日间精密度的相对标准偏差（RSD）均小于5.96%，方法学验证各指标及稳定性均符合分析要求。对所采集的10份糖尿病患者的尿液进行检测，并对该人群PAEs代谢物的暴露水平进行评价。结果表明，各PAEs代谢物均有检出，其中邻苯二甲酸单（2-乙基己基）酯（MEHP）的检出率为100%。总之，该方法萃取过程中未添加有毒的有机试剂，均使用多功能离子液体作为萃取剂、分散剂和盐析剂，萃取过程绿色环保，简单高效；方法的灵敏度较高，稳定性较好，适用于人体尿液中痕量PAEs代谢物的检测。     

相容的聚甲基丙烯酸甲酯/[C12 MIM][PF6]离子液体体系在超临界CO2中的发泡性能

通过快速卸压法, 以超临界CO2为物理发泡剂, 研究了相容的聚甲基丙烯酸甲酯(PMMA)/1-n-十二烷基-3-甲基咪唑六氟磷酸盐([C12 MIM][PF6])离子液体(IL)复合体系的发泡性能. 加入IL后, PMMA对CO2的吸收量增加; 复合体系的玻璃化转变温度(Tg)随IL含量的增加而降低. IL对PMMA发泡行为的影响取决于发泡条件. 在较低温度和压力下, 纯PMMA无法发泡, IL的加入可促进泡孔形成; 提高温度和压力, 纯PMMA可以发泡, IL的加入在提高泡孔尺寸的同时使泡孔仍然保持尺寸分布均匀的微米级结构.     

Antistatic ability of 1-n-tetradecyl-3-methylimidazolium bromide and its effects on the structure and properties of polypropylene

In this study, 1-n-tetradecyl-3-methylimidazolium bromide ([C₁₄mim]Br), one kind of imidazolium ionic liquid (imi-IL), was incorporated into polypropylene (PP) via melt blending. The measurement of surface resistance (R_s) and volume resistance (R_v) of neat PP and PP/[C₁₄mim]Br blends indicated that [C₁₄mim]Br had excellent antistatic properties. The PP/[C₁₄mim]Br blend had the best antistatic ability, when the weight ratio of [C₁₄mim]Br to PP reached 3/100. The surface resistance of PP/[C₁₄mim]Br decreased from the 7.67 × 10¹³ to 1.40 × 10⁷ Ω whereas the volume resistance of PP decreased from 2.67 × 10¹⁴ to 2.60 × 10⁷ Ω. Semicrystalline morphology and crystal structure were investigated by polarized optical microscopy (POM) and X-ray diffraction (XRD). The spherulites of PP became smaller with the addition of [C₁₄mim]Br, implying that [C₁₄mim]Br had a nucleating effect in the PP matrix. The XRD study indicates the crystallization process of PP was affected by [C₁₄mim]Br, and the crystallinity of PP was thus decreased. Scanning electron microscopy (SEM) studies reveal that [C₁₄mim]Br had good dispersion in PP; thermogravimetric analysis (TGA) shows the addition of [C₁₄mim]Br remarkably increased the thermal stability of PP even though it is a small molecule.     

咪唑基离子液体Br[C_(14)im](CH_2)_4[C_(14)im]Br对PP结构与性能的影响

应用Gemini型咪唑基离子液体和聚丙烯(PP)熔融共混,制备出Gemini型咪唑基离子液体改性PP,并对改性PP的结构与性能进行了表征与测试.研究结果表明,Br[C14im](CH2)4[C14im]Br添加到PP中后,起到了异相成核的作用,同时使PP晶体结晶度减小;添加离子液体的样品熔融峰温,结晶峰温与纯样相近,同时离子液体也诱导了PP中α晶的生成;Gemini型咪唑基离子液体可以提高PP的抗静电性能,加入量为3 phr时,表面电阻率为8.97×109Ωcm,抗静电性能优良;此外,添加离子液体后样品拉伸强度有所降低,冲击强度有所提高,断裂伸长率有所下降,降低了PP的玻璃化温度,说明离子液体对PP有增塑作用.     

离子热法制备多级孔AlPO_4-5分子筛

采用离子热法,以磷酸为磷源,γ-Al_2O_3为铝源,在1-丁基-3-甲基溴化咪唑离子液体中于320℃反应10 min内快速合成了多级孔AlPO_4-5分子筛,其结构和形貌经傅里叶红外光谱(FT-IR),X-射线衍射(XRD),扫描电子显微镜(SEM),氮气物理吸-脱附(BET)和透射电镜(TEM)表征。     

Nanostructural organization and anion effects in the optical Kerr effect spectra of binary ionic liquid mixtures

This article reports a study of the effect of anions on the optical Kerr effect (OKE) spectra of binary ionic liquid mixtures with one mixture comprising the 3-methyl-1-pentylimidazolium ([C 5mim] (+)) cation and the anions PF 6 (-) and CF 3CO 2 (-) (TFA (-)), and another mixture comprising the [C 5mim] (+) cation and the anions Br (-) and bis(trifluomethanesulfonyl)imide (NTf 2 (-)). The spectra were obtained by the use of optical heterodyne-detected Raman-induced Kerr Effect Spectroscopy at 295 K. The OKE spectra of the mixtures are compared with the calculated mole-fraction weighted sum of the normalized OKE spectra of the neat liquids. The OKE spectra are nearly additive for [C 5mim]Br/[C 5mim][NTf 2] mixtures, but nonadditive for [C 5mim][PF 6]/[C 5mim][TFA] mixtures. In the case of the equimolar [C 5mim][PF 6]/[C 5mim][TFA] mixture, the nonadditivity is such that the experimental OKE spectrum is narrower than the calculated OKE spectrum. The additivity or nonadditivity of OKE spectra for IL mixtures can be explained by assuming ionic liquids are nanostructurally organized into nonpolar regions and ionic networks. The ionic networks in mixtures will be characterized by "random co-networks" for anions that are nearly the same in size (PF 6 (-) and TFA (-)) and by "block co-networks" for anions that differ greatly in size (Br (-) and NTf 2 (-)).     

Melting and freezing behaviors of prototype ionic liquids, 1-butyl-3-methylimidazolium bromide and its chloride, studied by using a nano-Watt differential scanning calorimeter

1-Butyl-3-methylimidazolium bromide ([bmim]Br) and its chloride ([bmim]Cl) are representative prototypes of ionic liquids. We investigated the melting and freezing behaviors of [bmim]Br and [bmim]Cl by using a homemade differential scanning calorimeter (DSC) with nano-Watt stability and sensitivity. The measurements were carried out at heating and cooling rates slow enough to mimic quasi-static processes. Their thermal behaviors of melting and freezing show characteristic features such as a wide pre-melting range and excessive supercooling and individual behaviors of single crystals even for the same substance. The melting temperatures of [bmim]Br and [bmim]Cl were determined from the broad DSC traces and discussed in relation to the crystal structure. We suggest that the observed characteristics are due to the dynamics of the cooperative change between gauche-trans (GT) and trans-trans (TT) conformations of the butyl group in the [bmim]+ cation.     

Impact of imidazolium-based ionic liquid surfactant additions on dilational rheology properties of different protein adsorption layer

The interfacial behavior of β-casein and BSA solutions have been investigated in the presence of imidazolium-based ionic liquid surfactant ([C₁₄mim]Br) at the decane/water interface with the oscillating the drop and interfacial tension relaxation measurements. Both the electrostatic and the hydrophobic interaction between protein and [C₁₄mim]Br played crucial roles as [C₁₄mim]Br concentration increases. Furthermore, it was found that the dilational rheology parameters provided information of the adsorbed layers structure, and the dynamics properties of the adsorbed layers depend on the bulk [C₁₄mim]Br concentration. Moreover, with the concentration of [C₁₄mim]Br increasing, β-casein in the interfacial layer was subject to conformational changes where it gave space to [C₁₄mim]Br molecules in the form of co-adsorb; for BSA/[C₁₄mim]Br solutions, the globule protein BSA deformed and then co-adsorb with [C₁₄mim]Br molecules at the decane/water interface. These results will contribute to elucidation of the influence of the surfactant on the different structure proteins and the wide applications of protein/surfactant systems in practice.     

Role of C2 methylation and anion type on the physicochemical and thermal properties of imidazolium-based ionic liquids

This study focused on the effects of methylation and different anions (Br^? and Cl^?) on the physicochemical and thermal properties of [C₁₆MIM]X and [C₁₆MMIM]X, belonging to the imidazolium-based ionic liquid (IL) family. The effect of methylation on the transmittance in the fingerprint region of the Fourier transform infrared (FT-IR) spectrum was observed as a blue shift, and a new peak associated with the C-N stretching bond was obtained. In contrast, in the functional group region, the frequency shift was related to the change in the vibrational mode from C2-H-X to C2-methyl-X. In general, methylation resulted in an increase in decomposition temperature, an increase in melting temperature, and a decrease in melting enthalpy, leading to a reduction in entropy. The trends observed for the decomposition temperature, melting temperature, and melting enthalpy with different anions depended on the strength of the Brønsted acids and hydrogen bonds of the Br^? and Cl^? based anions. The thermal conductivity of the methylated ILs increased with an increase in temperature. In contrast, for the non-methylated (protonated) ILs, the thermal conductivity of [C₁₆MIM]Br decreased with an increase in temperature, while the opposite trend was observed for [C₁₆MIM]Cl. The data were compared with those of the short alkyl chain and weakly coordinating anion of NTf₂. The analysis was performed considering different phases, the prominent role and different behaviour in the hydrogen bonding at the C2 position of the imidazolium ring upon methylation, and the significant change in viscosity, which can influence the IL structure.     

Surface tension of binary mixtures of imidazolium and ammonium based ionic liquids with alcohols, or water: cation, anion effect

The surface tensions were measured at atmospheric pressure, with use of a ring tensiometer, of a series of alcoholic solutions of closely related ionic liquids: 1-methyl-3-methylimidazolium methylsulfate, [MMIM][CH3SO4] in alcohol (methanol, or ethanol, or 1-butanol at 298.15 K), 1-butyl-3-methylimidazolium methylsulfate, [BMIM][CH3SO4] in alcohol (methanol, or ethanol, or 1-butanol at 298.15 K), 1-butyl-3-methylimidazolium octylsulfate, [BMIM][OcSO4] in alcohol (methanol, or 1-butanol at 298.15 K) and of 1-hexyloxymethyl-3-methylimidazolium tetrafluoroborate, [C6H(13)OCH2MIM][BF4], 1,3-dihexyloxymethylimidazolium tetrafluoroborate, [(C6H13OCH2)2IM][BF4] in alcohol (methanol, or 1-butanol, or 1-hexanol at 308.15 and 318.5 K) and hexyl(2-hydroxyethyl)dimethylammonium bromide, C6Br in 1-octanol at 298.15 K. The set of ammonium ionic liquids of different cations and anions (C2Br, C2BF4, C2PF6, C2N(CN)2, C3Br, C4Br and C6Br) was chosen to show the influence of small amount of the ammonium ionic liquid on the surface tension of water at 298.15 K. The influence of the cation, or anion alkyl chain length on the properties under study (densities and surface tension) was tested.     

离子液体在多水相液液平衡体系中的作用

通过用短链离子液体(1-乙基-3-甲基咪唑溴盐[C2mim]Br、1-丁基-3-甲基咪唑溴盐[C4mim]Br)部分或全部取代SDS/DTAB/PEG/NaBr/H2O多水相体系中的无机盐NaBr,用长链离子液体十二烷基-3-甲基咪唑溴盐[C12mim]Br部分取代体系中阳离子表面活性剂DTAB,系统研究了离子液体在分相体系中的作用及其对分相体系性质的影响.研究表明,SDS/DTAB/PEG/NaBr/H2O混合体系形成的四水相体系可以看作"聚合物双水相"与"表面活性剂双水相"共存的结果.短链离子液体([C2mim]Br、[C4mim]Br)较强的亲水性能赋予其较强的盐析能力,在混合体系中表现出明显的盐效应,保证了四水相体系中"聚合物双水相"的存在.短链离子液体与聚合物之间的相互作用及其对表面活性剂之间相互作用的影响均不可忽略.对混合体系的相行为,共存多相的性质有重要的影响.而长链离子液体[C12mim]Br主要通过自身的疏水作用影响"表面活性剂双水相"的性质,充当表面活性剂的角色.然而,[C12mim]Br与DTAB分子结构上的差异,导致表面活性剂分子在"表面活性剂双水相"的两相重新分配,影响了对应两相的体积及萃取能力.可见,通过调节离子液体的烷基链长、混合体系中的含量等可获得具有特定性质的多水相体系.