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1.
Rodríguez O Cristóvão RO Tavares AP Macedo EA 《Applied biochemistry and biotechnology》2011,164(4):524-533
The activity and stability of laccase and their kinetic mechanisms in water soluble ionic liquids (ILs): 1-butyl-3-methyl
imidazolium chloride [C4mim][Cl], 1-octyl-3-methyl imidazolium chloride [C8mim][Cl], and 1-decyl-3-methyl imidazolium chloride [C10mim][Cl] were investigated. The results show that an IL concentration up to 10% is satisfactory for initial laccase activity
at pH 9.0. The laccase stability was well maintained in [C4mim][Cl] IL when compared to the control. The inactivation of laccase increases with the length of the alkyl chain in the
IL: [C10mim][Cl] > [C8mim][Cl] > [C4mim][Cl]. The kinetic studies in the presence of ABTS as substrate allowed calculating the Michaelis–Menten parameters. Among
the ILs, [C4mim][Cl] was the suitable choice attending to laccase activity and stability. Alkyl chains in the ions of ILs have a deactivating
effect on laccase, which increases strongly with the length of the alkyl chain. 相似文献
2.
Fatemeh Fadaei Michelle Seifert Joshua R. Raymond David eha Natalia Kulik Babak Minofar Mark P. Heitz 《Molecules (Basel, Switzerland)》2022,27(1)
Ionic liquids (ILs) have become nearly ubiquitous solvents and their interactions with biomolecules has been a focus of study. Here, we used the fluorescence emission of DAPI, a groove binding fluorophore, coupled with molecular dynamics (MD) simulations to report on interactions between imidazolium chloride ([Imn,1]+) ionic liquids and a synthetic DNA oligonucleotide composed entirely of T/A bases (7(TA)) to elucidate the effects ILs on a model DNA duplex. Spectral shifts on the order of 500–1000 cm−1, spectral broadening (~1000 cm−1), and excitation and emission intensity ratio changes combine to give evidence of an increased DAPI environment heterogeneity on added IL. Fluorescence lifetimes for DAPI/IL solutions yielded two time constants 0.15 ns (~80% to 60% contribution) and 2.36–2.71 ns for IL up to 250 mM. With DNA, three time constants were required that varied with added IL (0.33–0.15 ns (1–58% contribution), ~1.7–1.0 ns (~5% contribution), and 3.8–3.6 ns (94–39% contribution)). MD radial distribution functions revealed that π-π stacking interactions between the imidazolium ring were dominant at lower IL concentration and that electrostatic and hydrophobic interactions become more prominent as IL concentration increased. Alkyl chain alignment with DNA and IL-IL interactions also varied with IL. Collectively, our data showed that, at low IL concentration, IL was primarily bound to the DNA minor groove and with increased IL concentration the phosphate regions and major groove binding sites were also important contributors to the complete set of IL-DNA duplex interactions. 相似文献
3.
Densities and speeds of sound of three ionic liquids (ILs), 1-ethyl-3-methyl imidazoliumtetrafluoroborate (C2mimBF4), 1-butyl-3-methylimidazoliumtetrafluoroborate (C4mimBF4) and 1-hexyl-3-methylimidazoliumtetrafluoroborate (C6mimBF4) were measured in aqueous solutions at (288.15, 293.15, 298.15, 303.15 and 308.15) K. These data were used to calculate the volumetric properties apparent molar volume and apparent molar isentropic compression as a function of molality. Infinite dilution values for these properties were evaluated by an extrapolation procedure based on Redlich–Meyer type equations. Apparent molar isobaric expansions at infinite dilution were also obtained from the slopes of the apparent molar volume at infinite dilution versus temperature. All these properties are interpreted in terms of IL–water interactions. The hydrolysis of the \( {\text{BF}}_{4}^{ - } \) anion of the ILs and its effects on the results is discussed. 相似文献
4.
FangShengJIANG HuaYU GeGAO RuGangXIE 《中国化学快报》2005,16(3):321-324
Benzoin condensation promoted efficiently in three imidazolium based room temperature ionic liquids [bmim]Br, [bmim]BF4 and [Bnmim]BF4 is reported for the first time. Benzoins were obtained in up to 91% yield within less than 30 min under mild conditions. 相似文献
5.
运用密度泛函理论B3LYP方法及6-311++G(d,p)基组对11种咪唑氟硼酸离子液体进行了研究.选择相应化合物的离子体系{[XIM][BF4]n}(n-1)-(n=2,3)作为研究对象,即研究体系由一个烷基咪唑阳离子XIM+和2-3个BF4-阴离子构成,对其进行结构优化.在优化得到的最低能量构型的基础上计算了分子内阳离子与阴离子间的相互作用能,同时考虑了基组重叠误差的修正.结果表明所研究离子体系的离子间相互作用能与离子液体的实验熔点之间存在明确的线性关系,并且所得到的线性方程与氨基酸阳离子型离子液体中存在的线性关系相近.我们的工作为今后借助量子化学方法设计功能化离子液体提供了一定的理论基础. 相似文献
6.
Roohi Jan Ghulam Mohammad Rather Mohsin Ahmad Bhat 《Journal of solution chemistry》2014,43(4):685-695
Here we report a systematic study on electrical conductivity and surface tension of various concentrated solutions of imidazolium based room temperature ionic liquids (RTILs), viz. 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM][ $\hbox {PF}_{6}$ ]) and 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM][ $\hbox {BF}_{4}$ ]) in the cosolvents methanol and acetonitrile at 298.15 K. The aim of the investigations was to explore the impact of cosolvents on bulk and interfacial characteristics of imidazolium based RTILs. It was observed that both methanol and acetonitrile mix non-ideally with and enhance the transport parameters of the imidazolium based RTILs. An interesting outcome of the presented work is that the investigated RTILs retain their inherent structural characteristics up to a high dilution limit with cosolvent, and this limit is higher in acetonitrile than in methanol as cosolvent. The findings establish that, in comparison to methanol, acetonitrile is a better cosolvent that can be used for enhancing the transport parameters of imidazolium based RTILs for electrochemical and other applications. The results are explained in light of structure-composition-property relations and ion-ion and ion-cosolvent interactions. 相似文献
7.
A. Heintz J. K. Lehmann E. Schmidt A. Wandschneider 《Journal of solution chemistry》2009,38(8):1079-1083
Diffusion coefficients of the ionic liquids [C2MIM][EtSO4], [C4MIM][OcSO4], [C2MIM][NTf2] and [C4MIM][NTf2] in water at high dilution have been measured using the Taylor dispersion technique. Data on the diffusion coefficients have
been obtained for each solute at six temperatures between 288 and 313 K. The data have been fitted by the Arrhenius equation
and activation energies of diffusion have been determined. Effective radii of the ionic liquid molecules have also been obtained
using the Stokes–Einstein relationship. 相似文献
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9.
多羧基咪唑离子液体的酸性表征 总被引:9,自引:0,他引:9
通过电位滴定法测得多羧基咪唑离子液体的离解常数pKa值(25 ℃)在1.43~1.92范围内, 说明多羧基咪唑离子液体酸性接近乙二酸, 比丁二酸以及乙酸强. 由于多羧基咪唑离子液体结构中咪唑环具有较强的吸电子诱导效应, 使多羧基咪唑离子液体具有中等强度的酸性. 三羧基咪唑离子液体酸性比含相同阴离子的二羧基咪唑离子液体酸性强. 阳离子相同、阴离子不同的多羧基咪唑离子液体酸性强弱顺序为: HSO4- > NO3- > PF6- > H2PO4-> Cl-、Br- > CF3CO2- > BF4- > CF3SO3-. 同时, 吡啶红外光谱探针法研究表明, 多羧基咪唑离子液体具有Brønsted酸性. 相似文献
10.
Doklady Physical Chemistry - The comparative stability of ionic liquids containing alkyl-substituted imidazolium and phosphonium cations on exposure to gamma radiation (60Co source) under the same... 相似文献
11.
Synthesis of Multiester-appended and Multicarboxylic-appended Imidazolium Ionic Liquids 总被引:2,自引:0,他引:2
Wei Guo GENG Xuc Hui LI Le Fu WANG Hong Li DUAN Wei Ping PAN 《中国化学快报》2006,17(2):169-172
Currently ionic liquids (ILs) are attracting considerable interest as eco-friendly solventsfor the replacement of volatile organic solvents in organic synthesis and catalysis1.Low-melting ILs based on imidazolium cations have dominated this area over the … 相似文献
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13.
Recent advances in studies of ionic liquids (IL) and ionic liquid–solvent mixtures are reviewed. Selected experimental, simulation, and theoretical results for electrochemical, thermodynamical, and structural properties of IL and IL-solvent mixtures are described. Special attention is paid to phenomena that are not predicted by the classical theories of the electrical double layer or disagree strongly with these theories. We focus on structural properties, especially on distribution of ions near electrodes, on electrical double layer capacitance, on effects of confinement, including decay length of a dissjoining pressure between confinig plates, and on demixing phase transition. In particular, effects of the demixing phase transition on electrochemical properties of ionic liquid–solvent mixtures for different degrees of confinement are presented. 相似文献
14.
Stefan Schernich Dr. Mathias Laurin Dr. Yaroslava Lykhach Dr. Nataliya Tsud Dr. Marek Sobota Dr. Tomáš Skála Dr. Kevin C. Prince Dr. Nicola Taccardi Valentin Wagner Prof. Dr. Hans-Peter Steinrück Prof. Dr. Vladimír Matolín Prof. Dr. Peter Wasserscheid Prof. Dr. Jörg Libuda 《Chemphyschem》2013,14(16):3673-3677
15.
This article represents a step towards how to choose an ionic liquid as the solvent to improve metal ion (Ag+ and Pb2+) extraction. The liquid-liquid solvent extraction is proposed with the following imidazolium ionic liquids (ILs): 1-ethyl-3-ethylimidazolium,
or 1-butyl-3-ethylimidazolium, or 1-hexyl-3-ethylimidazolium bis{(trifluoromethyl)sylfonyl}imide [EEIM][NTf2], or [BEIM][NTf2], or [HEIM][NTf2], or 1-butyl-3-ethylimidazolium hexafluorophosphate [BEIM][PF6], or 1-hexyl-3-ethylimidazolium hexafluorophosphate [HEIM][PF6] and the popular 1-butyl-3-methylimidazolium hexafluorophosphate [BMIM][PF6] for comparison. The effect of anion type (NTf2− versus PF6−) and the effect of structural components of an ionic liquid including alkyl chain length at the cation and the ethyl substituent
instead methyl at the cation, on the extraction and re-extraction processes by using dithizone as a metal chelator, were studied
at 296 K. Dithizone was employed to form neutral metal-dithizone complexes with heavy metal ions to extract them from aqueous
solution into the ILs.
Electronic Supplementary Material The online version of this article () contains supplementary material, which is available to authorized users.
Presented at the 236th ACS National Meeting, August 17–21, Philadelphia, USA. 相似文献
16.
离子液体因其低挥发性,高热稳定性及在萃取金属离子方面的优良表现被认为是乏燃料后处理中萃取分离放射性核素的新一代绿色溶剂。但从乏燃料后处理强辐射的应用环境来看,需要首先对离子液体及其萃取体系的辐射效应进行系统研究和评估。本文以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( )和1-丁基-3-甲基咪唑三氟甲基磺酰亚胺酸盐( )为例,综述了我们在离子液体及其萃取体系的γ辐射效应方面的最新研究进展,内容包括纯离子液体在氮气气氛下的辐射效应,硝酸对离子液体辐射效应的影响,离子液体辐解产物的分离分析及γ辐照对离子液体体系萃取金属离子的影响等。基于以上研究对离子液体用于乏燃料后处理的可行性进行了评估,同时对离子液体及其萃取体系的辐射效应研究进行了展望。 相似文献
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在离子液体氯化-1-烯丙基-3-甲基咪唑(AmimCl)存在的条件下,利用水合肼对氧化石墨烯进行同步还原,制备了一种可稳定分散在N,N-二甲基甲酰胺(DMF)和乙酸丁酯等有机溶剂中的离子液体改性石墨烯(IL-G)。运用红外光谱(FTIR)、紫外-可见吸收光谱(UV-Vis)、热失重分析(TGA)、原子力显微镜(AFM)、拉曼光谱(Raman)、X射线电子衍射(XRD)和X射线光电子能谱(XPS)对制备的改性石墨烯进行结构性能测试,结果表明离子液体AmimCl与石墨烯之间存在π-π和阳离子-π的相互作用,能较好的吸附在石墨烯表面。TGA测试表明IL-G中离子液体的比例约为7.20wt%。同时,AFM结果显示改性石墨烯剥离在DMF中的平均厚度是0.962 nm。由于非共价改性石墨烯可再分散于DMF和乙酸丁酯中,通过紫外可见吸收光谱测得其最大分散浓度分别是1.69 mg·mL-1和1.12 mg·mL-1。 相似文献
19.
在离子液体氯化-1-烯丙基-3-甲基咪唑(AmimCl)存在的条件下,利用水合肼对氧化石墨烯进行同步还原,制备了一种可稳定分散在N,N-二甲基甲酰胺(DMF)和乙酸丁酯等有机溶剂中的离子液体改性石墨烯(IL-G)。运用红外光谱(FTIR)、紫外-可见吸收光谱(UV-Vis)、热失重分析(TGA)、原子力显微镜(AFM)、拉曼光谱(Raman)、X射线电子衍射(XRD)和X射线光电子能谱(XPS)对制备的改性石墨烯进行结构性能测试,结果表明离子液体AmimCl与石墨烯之间存在π-π和阳离子-π的相互作用,能较好的吸附在石墨烯表面。TGA测试表明IL-G中离子液体的比例约为7.20wt%。同时,AFM结果显示改性石墨烯剥离在DMF中的平均厚度是0.962nm。由于非共价改性石墨烯可再分散于DMF和乙酸丁酯中,通过紫外可见吸收光谱测得其最大分散浓度分别是1.69mg·mL-1和1.12mg·mL-1。 相似文献
20.
考察了一系列基于"甲壳"效应的离子液晶高分子poly(2,5-bis{[6-(4-butoxy-4?-imidazolium phenyl)k-alkyl]oxy carbonyl}styrene bis(fluoroborate)salts)Pk-6-BF4(k=4,8,12,16)的相行为和相结构.热重分析结果表明,该系列聚合物的热分解温度都在320?C以上,说明其均具有优异的热稳定性能.示差扫描量热仪结果表明,P4-6-BF4和P8-6-BF4仅表现出一个玻璃化转变,随着尾链的增长,P12-6-BF4和P16-6-BF4具有一个结晶熔融峰.偏光显微镜、一维广角X衍射、二维广角X衍射结果表明,该系列聚合物均形成稳定的近晶A相结构,并且随着烷烃尾链的增长,层间距增加、近晶结构内部分子堆积形式有所改变. 相似文献