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1.
Ionic Solvation in Aqueous and Nonaqueous Solutions 总被引:1,自引:0,他引:1
Hitoshi Ohtaki 《Monatshefte für Chemie / Chemical Monthly》2001,132(11):1237-1268
Summary. The history of studies on ionic solvation is briefly reviewed, and structural and dynamic properties of solvated ions in
aqueous and nonaqueous solutions are discussed. An emphasis is placed on ionic solvation in nonaqueous mixed solvents in which
preferential solvation of ions takes place. A new parameter for expressing the degree of preferential solvation of an ion
is proposed.
Received January 16, 2001. Accepted January 31, 2001 相似文献
2.
Mohammad Khodadadi-Moghaddam Aziz Habibi-Yangjeh Mohamad Reza Gholami 《Monatshefte für Chemie / Chemical Monthly》2009,140(3):329-334
Abstract Solvatochromic parameters (E
T
N, normalized polarity parameter; π*, dipolarity/polarizability; β, hydrogen-bond acceptor basicity; α, hydrogen-bond donor acidity) have been determined for binary mixtures of propan-2-ol, propan-1-ol, ethanol, methanol and
water with recently synthesized ionic liquid (IL; 2-hydroxyethylammonium formate) at 25 °C. In all solutions except aqueous
solution, E
T
N values of the media increase abruptly with the ILs mole fraction and then increase gradually to the value of pure IL. A synergistic
behavior is observed for the α parameter in all solutions. The behavior of π* and β are nearly ideal for all solutions except for solutions of methanol with the IL. The applicability of nearly ideal combined
binary solvent/Redlich–Kister equation was proved for the correlation of various solvatochromic parameters with solvent composition.
The correlation between the calculated and the experimental values of various parameters was in accordance with this model.
Solute–solvent and solvent–solvent interactions were applied to interpret the results.
Graphical Abstract Predicted values of solvatochromic parameters (SP) (E
T
N, normalized polarity parameter; π*, dipolarity/polarizability; β, hydrogen-bond acceptor basicity; α, hydrogen-bond donor acidity) from the correlation equations versus its experimental values for binary mixtures of 2-hydroxyethylammonium
formate with water, methanol, ethanol, propan-1-ol and propan-2-ol.
相似文献
3.
Yizhak Marcus 《Monatshefte für Chemie / Chemical Monthly》2001,132(11):1387-1411
Summary. The Kirkwood-Buff integrals for 18 completely miscible aqueous co-solvent binary mixtures have been recalculated from thermodynamic data, and
the volume-corrected preferential solvation parameters derived from them are presented. Also presented are these latter quantities
for 15 additional such mixtures, for which the volume correction has not been applied previously. The self-interaction of
the water, the mutual interaction of the water and the co-solvent, and the self-interaction of the co-solvent at infinite
dilution derived from these integrals and parameters are then discussed. The systems studied include aqueous hydrogen peroxide,
methanol, ethanol, 1- and 2-propanol, 2-methyl-2-propanol, 2,2,2-trifluoroethanol, 1,1,1,3,3,3-hexafluoro-2-propanol, ethane-1,2-diol,
glycerol, 2-methoxyethanol (at 313 and 343 K), 2-ethoxyethanol, 2-butoxyethanol, 2-aminoethanol, N-methyl- and N,N-dimethyl-2-aminoethanol,
tetrahydrofuran, 1,4-dioxane, acetone, formic, acetic, and propanoic acids, piperidine, pyridine, acetonitrile, formamide,
N-methyl- and N,N-dimethylformamide, N-methylacetamide, N-methylpyrrolidin-2-one (at 303 K), hexamethyl phosphoric triamide,
dimethylsulfoxide, and tetramethylenesulfone (at 303 K).
Received January 10, 2001. Accepted (revised) February 20, 2001 相似文献
4.
The partition of acetic acid between aqueous solutions and various binary mixtures of carbon tetrachloride + cyclohexane and
carbon tetrachloride + 1,2-dichloroethane were carried out at 30.0 °C. The nonlinear dependence of both the monomer partition
coefficient and the dimerization constant on the mole fraction composition has been rationalized in terms of preferential
solvation of the various solvation sites of the involved species. Two and four polar sites were identified for the monomer
and dimer forms, respectively. The solvation preference is controlled by the relative polarities of the binary solvent components,
being, in general, higher for the monomer sites compared to the dimer ones. The dimer is almost equally stable in various
carbon tetrachloride + 1,2-dichloroethane mixtures, and the variation of dimerization constants with changing binary composition
arises mainly from the monomer solvation stabilization. 相似文献
5.
The preferential solvation of water plays an important role in ferrocene research which is a subject of current interest. Voltammetric investigations were carried out for Au electrode in acetonitrile/water, showing preferential solvation of water. In our work, the preferential solvation of water in acetonitrile/water was studied by electrochemical methods including cyclic volitammetry, electrochemical impedance spectra and double‐step chronoamperometry. Ferrocenemethanol (FcCH2OH) molecules as a solute spontaneously adsorb on the electrode surface in anhydrous acetonitrile, resulting from acetonitrile molecules tend to form an acetonitrile solvent layer on the surface of the electrode and acetonitrile solvent layer has a lower energy barrier than the aqueous solvent layer, which has been obtained by modeling solvation. The solvent strongly influences electrochemical behavior of solute. Once there is an amount of water in acetonitrile solvent, FcCH2OH that adsorbed on the electrode surface desorb. This is because water preferentially solvate with FcCH2OH in term of intermolecular forces between solvent and solute. Moreover, hydrogen bond between water molecules and FcCH2OH molecules is stronger than dipole‐dipole interaction between acetonitrile molecules and FcCH2OH molecules in solvation effect. Through electrochemical behavior of FcCH2OH changing, preferential solvation of water is analyzed by electrochemical methods. 相似文献
6.
通过一步法合成了基于1,3-二烷基咪唑阳离子和甲烷磺酸或对甲苯磺酸阴离子的无卤素离子液体,并对它们的物理化学性质如聚集行为、表面性质、热性质、密度、黏度、折光率和电化学性质等进行了详细研究.结果表明在甲烷磺酸阴离子基离子液体中观察到离子液体中普遍存在的离子簇行为;同等条件下[BEim]MS的荧光光谱强度较[BEim]TS弱;[C12Mim]MS展现出液晶行为;[TS]-基离子液体有着较高的折光率,大于1.51. 相似文献
7.
Dr Andrew Dolan Dylan A. Sherman Prof. Rob Atkin Prof. Gregory G. Warr 《Chemphyschem》2016,17(19):3096-3101
The Kamlet–Taft solvent parameters of solvate ionic liquids (SILs) prepared from lithium salts with glyme and glycol ligands are determined. The dipolarity/polarisibilities (π*) are high, similar to those found in conventional ionic liquids. The H‐bond basicities (β) depend strongly on the anion. The H‐bond acidities (α) are high in both glyme and glycol SILs, indicating that the lithium is acting as a H‐bond donor site. “Poor” SILs have glyme‐rich and salt‐rich regions. In these liquids the π* and β values are almost identical to the parent glyme or glycol, and the α values are determined by the salt alone. 相似文献
8.
First Binary Mixture Ionic Liquids Containing EMIMBr and IM 总被引:1,自引:0,他引:1
LiYiDAI ChunYanHUA ShengRongYE YongKuiSHAN MingYuanHE 《中国化学快报》2003,14(6):634-636
A new series of binary mixture ionic liquids comprising 1-ethyl-3-methylimidozalium bromide(EMIMBr) and imidazole(IM) have been synthesized.The melting prints of the ionic liquids vary with te different content of IM while they still keey satisfactory conductivity and viscosity.According to the analysis of its phase diagram,the cutectic point is about 16.5℃ with the mass percentage of IM 29%. 相似文献
9.
Summary. In this study, the stoichiometric protonation constants, logKOH and logKNH, of sixteen substituted N-benzylidene-2-hydroxyanilines have been determined potentiometrically in ethanol-water mixtures of varying composition (10–80%
ethanol by volume) at 25.0±0.1°C. The values of the constants, logK, were submitted to factor analysis in order to obtain the number of factors which affect the variation of the whole data
sets of protonation constants and, afterwards, to target factor analysis to identify these factors. The influence of solvatochromic
parameters in the interactions between Schiff bases derivatives and the solvent studied was identified and quantified. Kamlet and Taft general equations allow calculation of the logK values of Schiff bases studied in any ethanol-water mixtures up to 80% (v/v) and thus provide the knowledge of the acid-base behaviour in these solvent media. Further, the quasi-lattice quasi-chemical
(QLQC) theory of preferential solvation has been applied to quantify the preferential solvation by water of electrolytes in
ethanol-water mixtures. 相似文献
10.
新型对称烷基咪唑离子液体介质中酶催化合成l-乙酸薄荷酯 总被引:4,自引:0,他引:4
设计合成三种新型对称烷基咪唑六氟磷酸盐离子液体——1,3-二正丁基咪唑六氟磷酸盐([DnBIM][PF6]), 1,3-二异丁基咪唑六氟磷酸盐([DiBIM][PF6])和1,3-二仲丁基咪唑六氟磷酸盐([DsBIM][PF6]). 以脂肪酶pseudomonas cepacia催化l-薄荷醇和乙酸酐的酯化过程为模型反应, 分别考察不同介质中酶的活性、反应性和稳定性, 结果表明作为反应介质三种新型离子液体均优于经典离子液体1-正丁基-3-甲基咪唑六氟磷酸盐和有机溶剂正己烷. 在三种新的离子液体中, [DiBIM][PF6]具有最好的亲生物性而被选择作为模型反应介质. 此外, 影响l-薄荷醇转化率的各种因素(包括反应温度、底物投料比、离子液体用量和含水量)及酶的重复利用性也被详细研究. 在最佳反应条件下, l-薄荷醇转化率达到97.4%, 酶促反应速度、平衡转化率和半衰期分别是正己烷中的12.7, 4.6和15.1倍. 脂肪酶重复使用10次后催化活性没有明显减少. 由于三种新型离子液体互为同分异构体, 以上事实还表明除憎水性和亲核性以外离子液体的空间构型也是影响酶行为的一个重要因素. 相似文献
11.
12.
二茂铁在几种离子液体中的迁移行为 总被引:2,自引:1,他引:2
采用循环伏安法研究了二茂铁(Fc)在几种离子液体中的迁移行为. 计算了Fc在各离子液体中的扩散系数和粘度系数,探讨了离子液体粘度与离子液体结构之间的关系. 实验结果表明, 离子液体的粘度随阳离子取代基碳链长度的增加而增加, 随阴离子对称性的增加而增加. 相似文献
13.
本文研究了在10种溶剂中0.5mol/L的Ca(ClO4)2中^35Cl的峰宽和6种溶剂中^35Cl峰宽随盐浓度的变化,讨论了离子缔合与溶剂性质及离子性质的关系;以乙晴或乙醇作溶剂,在Ca(ClO4)2浓度固定时,观察^35Cl峰宽随第2溶剂组分B(此处B为H2O或DMF)的加入量(以[B]/[Ca^2 ]表示)的变化,讨论了变化规律、原因及钙离子被水或DMF的溶剂化数;还结合电导数据,讨论了Ca^2 离子与ClO4^-离子的相互作用和缔合形式。 相似文献
14.
Polyethylene glycols have become more popular alternate reaction media due to interesting properties like non-toxicity, bio-degradability, and full miscibility with water and organic solvents. Binary mixtures of polyethylene glycols with common solvents can be useful to tune their physical and chemical properties and to facilitate chemical and physical processes. In this study, solvatochromic parameters were spectrophotometrically determined for binary solvent mixtures of poly(ethylene glycol)-400 (PEG-400) with methanol, 2-propanol, 1-butanol, dimethyl sulfoxide, N,N-Dimethylformamide, and dichloromethane under ambient conditions, over the whole range of mole fractions. The solvatochromic parameters showed different trends in protic and aprotic solvents mixed with PEG-400. Methanol/PEG-400 mixtures showed special properties in polarity and polarizability so that the mixtures are more dipolar/polarizable than their pure components. Positive or negative deviations from ideal behavior confirmed that the indicators were involved in a preferential solvation process in the solvent mixtures. These deviations from ideality can be attributed to strong solvent–solvent interactions in the binary mixtures. 相似文献
15.
Study of Microheterogeneity in Acetonitrile–Water Binary Mixtures by using Polarity‐Resolved Solvation Dynamics 下载免费PDF全文
The solvation dynamics of three coumarin dyes with widely varying polarities were studied in acetonitrile–water (ACN–H2O) mixtures across the entire composition range. At low ACN concentrations [ACN mole fractions (XACN)≤0.1], the solvation dynamics are fast (<40 ps), indicating a nearly homogeneous environment. This fast region is followed by a sudden retardation of the average solvation time (230–1120 ps) at higher ACN concentrations (XACN≈0.2), thus indicating the onset of nonideality within the mixture that continues until XACN≈0.8. This nonideality regime (XACN≈0.2–0.8) comprises of multiple dye‐dependent anomalous regions. At very high ACN concentrations (XACN≈0.8–1), the ACN–H2O mixtures regain homogeneity, with faster solvation times. The source of the inherent nonideality of the ACN–H2O mixtures is a subject of debate. However, a careful examination of the widths of time‐resolved emission spectra shows that the origin of the slow dynamics may be due to the diffusion of polar solvent molecules into the first solvation shell of the excited coumarin dipole. 相似文献
16.
ROW Kyung Ho 《高等学校化学研究》2009,25(3)
Several chromatography systems with ionic liquids and a mixture of water with the modifier as mobile phase were characterized via the linear solvation energy relationships(LSER) model. The effects of the ionic liquids and modifier(methanol) concentrations on the retention of 10 solutes(caffeine,pyridine,aniline,phenol,methylparaben,acetopenone,m-cresol,p-cresol,o-cresol,and benzene) were discussed. The LSER model demonstrated high potential to predict retention factors with high squared correlation coeffici... 相似文献
17.
18.
ZhangGaoLE ZhenChuCHEN YiHU QinGuoZHENG 《中国化学快报》2005,16(2):155-158
1-(α-Alkoxyalkyl)benzotriazoles are readily synthesized from three-component condensation of benzotriazole with aldehyde and alcohol in ionic liquid [Bmim]PF6. 相似文献
19.
In this paper, a survey has been undertaken to clarify the possible reasons for the electrocatalytic activity obtained by the presence of ionic liquid in carbon paste electrode (CPE). For this purpose, the effect of the addition of traces of ionic liquid to conventional CPE was investigated. Fe(CN)63?/4? was used as a probe and two ionic liquids, namely n‐octylpyridinum hexafluorophosphate and 1‐octyl‐3‐methylimidazolium hexaflourophosphate were tested for their electrocatalytic activity. The reasons for this electrocatalytic behavior were evaluated and it was found that different factors such as increase in the ionic conduction of the binder, decrease in the resistance of the modified electrode, increase in ion exchange properties of the electrode and the inherent catalytic activity of ionic liquids are responsible for the considerable improved electrochemical response obtained in the presence of traces of ionic liquid. 相似文献