共查询到20条相似文献,搜索用时 31 毫秒
1.
近年来,温室效应日趋严重,因此吸收CO_2的材料受到了广泛的关注.采用了密度泛函理论(DFT)研究以SiO_2为载体的限域离子液体对CO_2的吸附.对比纯净离子液体(ILs)以及限域离子液体与CO_2的相互作用情况,在这两种状态下两种体系的吸附情况大不相同.从几何结构、相互作用以及电荷分析等方面对ILs、 SiO_2以及ILs/SiO_2复合结构进行研究.计算结果表明,载体、离子液体和CO_2之间都存在较强的相互作用.离子液体的负载不仅改变了SiO_2载体的结构,而且受载体的影响阴阳离子之间的相互作用力也发生了改变.计算结果为进一步深入限域离子液体对CO_2的吸附打下了理论基础. 相似文献
2.
3.
4.
5.
6.
《印度化学会志》2021,98(11):100205
Due to the increasing trend to use ionic liquids (ILs) for number of applications, it is of utmost importance to ensure non toxicity of the solvent systems which may contaminate the processed products. The reported toxicity of several imidazolium based ionic liquids posed a need to develop bio based ILs for various applications which are due to their bio-origin are bio compatible, nontoxic and biodegradable. Herein eleven bio-based ionic liquids were prepared using acid moieties available in various plants and characterized. Although some of the ILs were used to separate antibodies such as IgG from rat serum in the form of aqueous biphasic systems but to find their direct application for material preparation and food applications, herein rheological behavior of the ILs were investigated. The choline based IL containing coumarine-3-carboxylate was found to have highest zero shear viscosity while the IL with D-(−)-quinate was found to have the lowest. The viscoelastic behavior of the ionic liquids established anion dependent viscous and liquid like behavior of the ionic liquids. Interestingly the ILs showed viscosity independent ion conductivity. Due to the high conductivity, stable physical state and bio-origin such ILs have the potential for applications in electrochemistry, food and material science. 相似文献
7.
以H2O2为氧化剂,研究了离子液体为催化剂和溶剂,环己烯氧化生成反-1,2-环己二醇的反应。 考察了不同咪唑型离子液体、反应时间、反应温度和H2O2用量等对产率和选择性的影响, 实验结果表明,在7种咪唑型离子液体催化体系中,阳离子为咪唑环上含有1或2个羧基,阴离子为[PF6]的离子液体催化效果较好。 反应温度为100 ℃,n(H2O2)∶n(Cyclohexene)=1.1∶1,反应5 h时,离子液体c(0.60 g,2.1 mmol)催化生成的反-1,2-环己二醇的产率和选择性分别为95%和97%,而离子液体f(0.20 g,0.6 mmol)催化生成的反-1,2-环己二醇的产率和选择性分别为84%和90%,从离子液体的用量来看,含2个羧基的离子液体f的催化效率更高。 相似文献
8.
Liquid phase behavior of ionic liquids with alcohols: experimental studies and modeling 总被引:3,自引:0,他引:3
Crosthwaite JM Muldoon MJ Aki SN Maginn EJ Brennecke JF 《The journal of physical chemistry. B》2006,110(18):9354-9361
Ionic liquids (ILs) have been suggested as potential "green" solvents to replace volatile organic solvents in reaction and separation processes due to their negligible vapor pressure. To develop ILs for these applications, it is important to gain a fundamental understanding of the factors that control the phase behavior of ionic liquids with other liquids. In this work, we continue our study of the effect of chemical and structural factors on the phase behavior of ionic liquids with alcohols, focusing on pyridinium ILs for comparison to imidazolium ILs from our previous studies. The impact of different alcohol and IL characteristics, including alcohol chain length, cation alkyl chain length, anion, different substituent groups on the pyridinium cation, and type of cation (pyridinium vs imidazolium) will be discussed. In general, the same type of behavior is observed for pyridinium and imidazolium ILs, with all systems studied exhibiting upper critical solution temperature behavior. The impacts of alcohol chain length, cation chain length, and anion, are the same for pyridinium ILs as those observed previously for imidazolium ILs. However, the effect of cation type on the phase behavior is dependent on the strength of the cation-anion interaction. Additionally, all systems from this study and our previous work for imidazolium ILs were modeled using the nonrandom two-liquid (NRTL) equation using two different approaches for determining the adjustable parameters. For all systems, the NRTL equation with binary interaction parameters with a linear temperature dependence provided a good fit of the experimental data. 相似文献
9.
Swantje Lerch Prof. Dr. Thomas Strassner 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(62):15554-15557
Tunable aryl alkyl ionic liquids (TAAILs) based on the imidazolium cation were first reported in 2009. Since then, a series of TAAILs with different properties due to the electron-donating or -withdrawing effect of the substituents at the aryl ring has been developed. Herein, a wide variety of those ionic liquids (ILs) is presented in terms of their cation structure. The authors synthesized ILs containing the bromide or bis(trifluoromethane)sulfonimide anion and 1-aryl-3-alkyl imidazolium cations with various substituents in the ortho and/ or para position of the phenyl ring and alkyl chains of different lengths varying from butyl to dodecyl. The differences of their physical properties (melting point, thermal decomposition, viscosity, electro-chemical window) of these ILs are reported according to their structure. 相似文献
10.
Dr. Shruti Trivedi Sidney G. Coombs Durgesh V. Wagle Nakara Bhawawet Prof. Gary A. Baker Prof. Frank V. Bright 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(33):11677-11684
To develop ionic liquid/porous silicon (IL/pSi) microarrays we have contact pin‐printed 20 hydrophobic and hydrophilic ionic liquids onto as‐prepared, hydrogen‐passivated porous silicon (ap‐pSi) and then determined the individual IL spot size, shape and associated pSi surface chemistry. The results reveal that the hydrophobic ionic liquids oxidize the ap‐pSi slightly. In contrast, the hydrophilic ionic liquids lead to heavily oxidized pSi (i.e., ox‐pSi). The strong oxidation arises from residual water within the hydrophilic ILs that is delivered from these ILs into the ap‐pSi matrix causing oxidation. This phenomenon is less of an issue in the hydrophobic ILs because their water solubility is substantially lower. 相似文献
11.
提出了关于离子液体的新理论——离子交换跃迁模型,通过理论推导得出1:1型离子液体的Walden乘积仅取决于离子对和离子簇直径的统计平均值,即离子液体的阴阳离子结构不同,Walden乘积不同。为了验证模型的正确性,本文合成8种N-烷基-吡啶二氰胺类和N-烷基-咪唑丝氨酸类离子液体,利用上述离子液体的电导率和动力粘度的实验值及文献数据,计算了33种离子液体的Walden乘积。通过比较发现,不同离子液体的Walden乘积不同,即对于离子液体来说,Walden乘积是它的特征物理量。 相似文献
12.
An extension of the Ye and Shreeve group contribution method [C. Ye, J.M. Shreeve, J. Phys. Chem. A 111 (2007) 1456–1461] for the estimation of densities of ionic liquids (ILs) is here proposed. The new version here presented allows the estimation of densities of ionic liquids in wide ranges of temperature and pressure using the previously proposed parameter table. Coefficients of new density correlation proposed were estimated using experimental densities of nine imidazolium-based ionic liquids. The new density correlation was tested against experimental densities available in literature for ionic liquids based on imidazolium, pyridinium, pyrrolidinium and phosphonium cations. Predicted densities are in good agreement with experimental literature data in a wide range of temperatures (273.15–393.15 K) and pressures (0.10–100 MPa). For imidazolium-based ILs, the mean percent deviation (MPD) is 0.45% and 1.49% for phosphonium-based ILs. A low MPD ranging from 0.41% to 1.57% was also observed for pyridinium and pyrrolidinium-based ILs. 相似文献
13.
Tyler Batchelor Joe Cunder Alexander Y. Fadeev 《Journal of colloid and interface science》2009,330(2):415-420
In this work, we present a systematic contact angles study of a series of 1-alkyl, 3-methyl-imidazolium ionic liquids (ILs) on well-defined polar and nonpolar monolayer surfaces supported on Si wafers. The advancing and receding contact angles of ILs were used to determine the surface energy of the monolayer surfaces using Neumann's equation-of-state and Zisman's critical surface tension approaches. In parallel, the contact angles of conventional probe fluids (molecular liquids) including water, formamide, methylene iodide, ethylene glycol, and hexadecane were determined on the same surfaces. The results obtained showed a great deal of similarity in wetting behavior of ionic vs molecular probe fluids: the contact angles of both sets of liquids followed the same patterns in accord with the surface tension of the fluid. A good agreement was found between the surface energy determined by different sets of liquids. 相似文献
14.
Juliusz Pernak Anna ?wierczyńskaMariusz Kot Filip WalkiewiczHieronim Maciejewski 《Tetrahedron letters》2011,52(33):4342-4345
Pyrylium salts represent a new group of ionic liquids (ILs) containing a positive charge on the oxygen atom. The novel ILs were obtained starting with 4-pyrones from petroleum feedstock and renewable resources and sulfonic acids. The use of carboxylic acids instead of salts resulted in the formation of cocrystals. The synthesized pyrylium ionic liquids were stable in air and in contact with water and common organic solvents. The permanganate indices which are characteristic for prepared sulfonates were also investigated. The pyrylium ionic liquids were useful as immobilizers and dissolving agents in hydrosilylation reactions. 相似文献
15.
Zhuo K Chen Y Chen J Bai G Wang J 《Physical chemistry chemical physics : PCCP》2011,13(32):14542-14549
Extensive applications of ionic liquids (ILs) may result in their accumulation in the ecological environment and organisms. Although ILs are popularly called "green solvents", their toxicity, in fact, has been exhibited. Therefore the interaction of ILs with biomolecules is a cutting-edge research subject. Herein, the interactions of 1-butyl-3-methylimidazolium carboxylate ionic liquids ([C(4)mim][HCOO], [C(4)mim][CH(3)COO] and [C(4)mim][CH(3)CH(2)COO]) with glucose in water were studied for their volumetric properties, viscosity, conductivity and NMR spectra. Limiting apparent molar volumes (V(Φ, IL)(0)), viscosity B-coefficients, limiting molar conductivities (Λ(0)) and Walden products (Λ(0)η(0)) were evaluated for the ILs in glucose + water solutions. Volumetric interaction parameters were also obtained from the transfer volumes of the ionic liquids. The contributions of the solvent properties (B(1)) and the ionic liquid-solvent interactions (B(2)) to the B-coefficient were extracted, together with molar activation energies (Δμ(IL)(0≠)) of the ionic liquids for viscous flow of the aqueous glucose + IL solution. In addition, the (13)C and (1)H NMR spectra of methyl β-D-glucopyranoside and ILs in β-D-glucopyranoside + IL + D(2)O were studied. The NMR results show that no special and strong interactions were observed between glucopyranoside and the ILs. However, it was confirmed that the H2 on the imidazolium ring has more activity (acidity) than atoms H4 and H5. The macro-properties and their changes were also discussed in terms of the size, structure and solvation of the ILs and glucose. 相似文献
16.
Novel halogen-free chelated orthoborate-phosphonium ionic liquids: synthesis and tribophysical properties 总被引:1,自引:0,他引:1
Shah FU Glavatskih S MacFarlane DR Somers A Forsyth M Antzutkin ON 《Physical chemistry chemical physics : PCCP》2011,13(28):12865-12873
We report on the synthesis, characterisation, and physical and tribological properties of halogen-free ionic liquids based on various chelated orthoborate anions with different phosphonium cations, both without halogen atoms in their structure. Important physical properties of the ILs including glass transition temperatures, density, viscosity and ionic conductivity were measured and are reported here. All of these new halogen-free orthoborate ionic liquids (hf-BILs) are hydrophobic and hydrolytically stable liquids at room temperature. As lubricants, these hf-BILs exhibit considerably better antiwear and friction reducing properties under boundary lubrication conditions for steel-aluminium contacts as compared with fully formulated (15W-50 grade) engine oil. Being halogen free these hf-BILs offer a more environmentally benign alternative to ILs being currently developed for lubricant applications. 相似文献
17.
《合成通讯》2013,43(17):3083-3089
Abstract New room‐temperature ionic liquids (ILs) were prepared by neutralization of 1,1,3,3‐tetramethylguanidine with different acids under ambient condition. The density, viscosity, decomposition temperature, electronic conductivity, and miscibility with some commonly used solvents were determined. As an example of the applications of the new ILs, the reaction of benzaldehyde, aniline, and acetophenone was carried out in the ILs. The ILs are easily prepared in large scale. 相似文献
18.
19.
In this study, ionic liquids (ILs) as BGE additives were applied for the analysis of neutral carbohydrates in CE. The ILs served primarily as chromophores for indirect UV detection. The influence of imidazolium-based ionic liquids on the separation, detection limits and mobility of underivatized neutral carbohydrates was investigated. BGEs consisting of 10-50 mM of ILs at pH 12.4 without other additives provided fast separation of neutral sugars. This method was used to determine sucrose, glucose and fructose in certain vegetable juices. 相似文献