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1.
A dielectric relaxation study has been made over a frequency range of 106–10–3 Hz in the supercooled liquid state of the binary mixtures of 2-ethyl-1-hexanol (2EHOH) with a wide variety of common liquids. Differential scanning calorimetry measurements have also been made above 100 K. Our studies show compatibility of the methylcyclohexane with 2EHOH over the entire composition range. However, in the case of 1-bromobutane and acetone with 2EHOH, we have clearly seen two liquidlike phases separating out, which indicates incompatibility. In the case of 4-methyl-2-pentanol, the binary liquid shows no heterogeneity over most of the concentration range. In the case of methyl alcohol (MOH), the binary liquid shows some heterogeneity at a molecular level in the MOH-rich region. An attempt has been made to understand miscibility in terms of the preference for ring and chain formation among the alcohol molecules. 相似文献
2.
Yizhak Marcus 《Journal of solution chemistry》2006,35(2):251-277
The Kirkwood–Buff integrals and the volume-corrected preferential solvation parameters for the first solvation shell of binary
mixtures of tetrahydrofuran with many organic solvents, calculated from reported thermodynamic data at the temperatures for
which these data were available, are reported. The co-solvents include c-hexane, methyl-c-hexane, n-heptane, i-octane, benzene, toluene, ethylbenzene, 1-chlorobutane, dichloromethane, 1,2-dichloroethane, chloroform, 1,1,1-trichloroethane,
tetrachlorom-ethane, tetrachloroethene, hexafluoro benzene, ethanol, 1-propanol, 2-propanol, dibutyl ether, acetic acid, acetone,
dimethyl sulfoxide, tetramethylene sulfone (sulfolane), acetonitrile, pyrrolidine, and triethylamine. The preferential solvation
parameters of these mixtures are discussed in terms of the interactions that occur. 相似文献
3.
Steady-state and time-resolved infrared spectroscopy of the azide (N(3)-) anion has been used to characterize aqueous mixtures both with the ionic liquid (IL) 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM][BF(4)]) and with dimethyl sulfoxide (DMSO). In the DMSO-water mixtures, two anion vibrational bands are observed for low water mole fractions (0 > X(w) > 0.25), which indicates a heterogeneous ion solvation environment. The band at 2000 cm(-1) observed for neat DMSO does not shift but decreases in amplitude as the amount of water is increased. Another band appears at slightly higher frequency at low X(w) (=0.05). As the amount of water is increased, this band shifts to higher frequency and becomes stronger and is attributed to azide with an increasing degree of hydration. At intermediate and high X(w), a single band is observed that shifts almost linearly with water mole fraction toward the bulk water value. The heterogeneity is evident from the infrared pump-probe studies in which the decay times depend on probe frequency at low mole fraction. For the azide spectra in IL-water mixtures, a single azide band is observed for each mole fraction mixture. The azide band shifts almost linearly with mole fraction, indicating nearly ideal mixing behavior. As with the DMSO-water mixtures, the time-resolved IR decay times are probe-frequency-dependent at low mole fraction, again indicating heterogeneous solvation. In both the DMSO and IL mixtures with water, the relaxation times are slower than would be expected from ideal mixing, suggesting that vibrational relaxation of azide is more sensitive than its vibrational frequency to the solvent structure. The results are discussed in terms of preferential solvation and the degree to which the azide shift and vibrational relaxation depend on the degree of water association in the mixtures. 相似文献
4.
《Advances in Molecular Relaxation and Interaction Processes》1979,14(3):163-184
Absorption of ultrasonic waves has been investigated in the mixture of acetic acid and tetrachloromethane covering the complete concentration range. Measurements have been carried out at 20, 30 and 40°C within a frequency range from 3 to 57 MHz for strongly absorbing mixtures (rich in acetic acid) and 5–57 MHz for mixtures with lower absorption. At about 0.01 mole fraction of acetic acid a relaxation has been observed with a relaxation frequency of 20 MHz increasing rapidly with increasing concentration, so that its observation has become impossible at mole fractions of acid bigger than 0.07. At higher acid concentrations the well known low frequency relaxation has been observed. The relaxations are discussed in terms of coupled dimerization and cyclization reaction of acetic acid including the nonideality of the mixture. In this model the faster relaxation seems to be caused by the dimerization reaction. 相似文献
5.
Excess enthalpies of binary mixtures between each of alkane-1-amines {CnH2n+1NH2, n=3-8} and methyl methylthiomethyl sulfoxide (MMTSO) or dimethyl sulfoxide (DMSO) have been determined at 298.15 K. All mixtures showed positive enthalpy changes over the whole range of mole fractions.The limiting excess partial molar enthalpies of the aliphatic amines, H1E,∞, of all the mixtures with MMTSO or DMSO studied were smaller than those of MMTSO or DMSO, H2E,∞, respectively. Linear relations are obtained between limiting excess partial molar enthalpies and number of methylene groups. 相似文献
6.
T. Kimura T. Sato M. Hirota S. Takagi 《Journal of Thermal Analysis and Calorimetry》2008,92(2):381-389
Excess enthalpies of sixteen binary mixtures between one each of methyl methylthiomethyl sulfoxide (MMTSO) and dimethyl sulfoxide
(DMSO) and one of ketone {CH3CO(CH2)nCH3, n=0 to 6 and CH3COC6H5} have been determined at 298.15 K. All the mixtures showed positive excess enthalpies over the whole range of mole fractions.
Excess enthalpies of ketone+MMTSO or DMSO increased with increasing the number of methylene radicals in the methyl alkyl ketone
molecules. Excess enthalpies of MMTSO+ketone are smaller than those of DMSO+ketone for the same ketone mixtures. The limiting
excess partial molar enthalpies of the ketone, H
1
E,∞, in all the mixtures with MMTSO were smaller than those of DMSO. Linear relationships were obtained between limiting excess
partial molar enthalpies and the number of methylene groups except 2-propanone. 相似文献
7.
Proton NMR spectroscopy was used to study the complexation reaction of 18-crown-6 (18C6) with K+, Rb+ and Tl+ ions in a number of binary dimethyl sulfoxide-nitrobenzene mixtures. In all cases, the exchange between free and complexed
crowns was fast on the NMR time scale and only a single population average 1H signal was observed. Formation constants of the resulting 1:1 complexes in different solvent mixtures were determined by
computer fitting of the chemical shift-mole ratio data. There is an inverse relationship between the complex stability and
the amount of dimethyl sulfoxide in the mixed solvent. It was found that, in all solvent mixtures used, Rb+ ion forms the most stable complex with 18-crown-6 in the series. 相似文献
8.
Novel bromo-substituted derivatives of dibenzo-tetraaza and dibenzo-dioxadiaza[14]annulenes B–G were synthesized by a twofold condensation reaction of a symmetrical bromo-substituted vinamidinum salt A with ortho-diamino- and ortho-amino-hydroxyarenes such as 1,2-diaminobenzene, 1,2-diamino-4,5-dimethylbenzene, 2,3-diaminonaphthalene, 1,2-diamino-4-methylbenzene, 2-amino-1-hydroxybnzene, and 2-amino-1-hydroxy-5-methyl-benzene in acetonitrile/acetic acid as reaction medium. The ultraviolet/visible spectral behavior of these [14]annulenes was examined in dimethyl sulfoxide (DMSO). Elemental analysis, infrared, 1H NMR, 13C NMR, and mass spectra confirm the molecular structure of the newly synthesized compounds. 相似文献
9.
Shiraz A. Markarian Liana S. Gabrielyan Karine R. Grigoryan 《Journal of solution chemistry》2004,33(8):1005-1015
FT IR ATR spectra of urea/dimethyl sulfoxide and urea/diethyl sulfoxide mixtures in the S=O and N—H stretching vibration regions at different molar ratios have been measured. On the basis of the band deconvolution data, various types of intermolecular associated forms, including dimers and hydrogen-bonded urea–sulfoxide complexes, have been revealed. The latter has been confirmed also by ab initio calculations. 相似文献
10.
Within the framework of stationary optical spectroscopy, a method for estimation of nonradiative relaxation efficiency for the electronically excited state of a fluorophore is suggested using 3,3-diethylthiacarbocyanine iodide solutions in binary mixtures of toluene and dimethyl sulfoxide (DMSO) as an example. In particular, the quantum yield of dye photoisomerization was found to noticeably decrease upon reducing DMSO content in the mixture. 相似文献
11.
《Physics and Chemistry of Liquids》2012,50(2):207-213
Excess molar polarization in the binary mixture of polar solutes (acetic acid, n-tributyl phosphate) in nonpolar solvents (benzene, tetrachloromethane, p-xylene) is evaluated with the help of our proposed equation. The results have been compared with those obtained from a previously proposed equation. It is observed that our proposed equation is more accurate to interpret the liquid structure and molecular association in the binary liquid mixtures. 相似文献
12.
Comparative Investigation of the Ionicity of Aprotic and Protic Ionic Liquids in Molecular Solvents by using Conductometry and NMR Spectroscopy
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Electrical conductivity (σ), viscosity (η), and self‐diffusion coefficient (D) measurements of binary mixtures of aprotic and protic imidazolium‐based ionic liquids with water, dimethyl sulfoxide, and ethylene glycol were measured from 293.15 to 323.15 K. The temperature dependence study reveals typical Arrhenius behavior. The ionicities of aprotic ionic liquids were observed to be higher than those of protic ionic liquids in these solvents. The aprotic ionic liquid, 1‐butyl‐3‐methylimidazolium tetrafluoroborate, [bmIm][BF4], displays 100 % ionicity in both water and ethylene glycol. The protic ionic liquids in both water and ethylene glycol are classed as good ionic candidates, whereas in DMSO they are classed as having a poor ionic nature. The solvation dynamics of the ionic species of the ionic liquids are illustrated on the basis of the 1H NMR chemical shifts of the ionic liquids. The self‐diffusion coefficients D of the cation and anion of [HmIm][CH3COO] in D2O and in [D6]DMSO are determined by using 1H nuclei with pulsed field gradient spin‐echo NMR spectroscopy. 相似文献
13.
Hindered internal rotation about the C‐N single bonds joining the thiuram disulfide was studied by 1H NMR complete line‐shaped analysis in different dimethyl sulfoxide‐chloroform (DMSO‐CDCl3) mixtures. From the temperature dependence of methyls proton spectra, activation parameters (Ea, ΔH≠, ΔS≠, and ΔG≠) were obtained. The Arrhenius plots showed a distinct isokinetic temperature at about 35 °C at which the exchange rate is more or less independent of the solvent composition. The resulting ΔH≠ against TΔS≠ plot showed a firmly good linear correlation, indicating the existence of an enthalpy‐entropy composition in an exchange process. 相似文献
14.
《Physics and Chemistry of Liquids》2012,50(4):229-235
Abstract The ultrasonic velocity, density and viscosity in binary mixtures of TBP with a number of aliphatic primary alcohols viz. methanol, ethanol, 1-hexanol, 1-heptanol, 1-octanol and 1-decanol have been measured at frequency 3 MHz and at temperature 303.16 K. The data are used to compute excess internal pressure and excess enthalpy in these mixtures. The results corroborate the findings of these authors from dielectric studies that the interaction is maximum in 1 heptanol-TBP system and microheterogeneous β-clusters with antiparaliel orientation of dissimilar molecules predominate in it. 相似文献
15.
Reverse atom transfer radical polymerization (RATRP) has been successfully applied in the synthesis of polyacrylonitrile (PAN) with FeCl3/acetic acid as catalyst in the presence of conventional initiator azobisisobutyronitrile (AIBN) at 65°C in N,N-dimethylformamide (DMF). A FeCl3 to acetic acid ratio of 1:2 not only gave better control on polymer's molecular weight and its distribution, but also provided a rapid polymerization rate compared with any other molar ratio of FeCl3 to acetic acid. The polymerization rate increased with increasing temperature and the apparent activation energy was calculated to be 80.6 kJ·mol?1. In comparison with dimethyl sulfoxide, acetonitrile, cyclohexanone and ethyl acetate, DMF was considered to be the best solvent of the polymerization for its polarity. Analysis of 1H-NMR further confirmed the living nature of the polymerization. 相似文献
16.
V. S. Baranovskii R. V. Simchak B. D. Grishchuk 《Russian Journal of General Chemistry》2009,79(2):269-273
Reactions of arenediazonium tetrafluoroborates with methacrylamide in the presence of potassium thiocyanate in aqueous acetone (1: 2.5) or aqueous dimethyl sulfoxide (1: 4) gave the corresponding 3-aryl-2-methyl-2-thiocyanatopropanamides which underwent heterocyclization in boiling acetic anhydride to produce difficultly accessible 2-(acetyl)amino-5-benzylthiazol-4(5H)-ones. 相似文献
17.
18.
The rate constants of alkaline fading of a number of triphenylmethane (TPM) dyes including methyl green (ME2+), brilliant green (BG+), fuchsin acid (FA2?), and bromophenol blue (BPB2?) were obtained in aqueous binary mixtures of 2‐propanol (protic solvent) and dimethyl sulfoxide (DMSO) (aprotic solvent) at different temperatures. It was observed that the reaction rate constants of BG+ and ME2+ increased and those of FA2? and BPB2? decreased with an increase in weight percentages of aqueous 2‐propanol and DMSO binary mixtures. 2‐Propanol and DMSO interact with the used TPM molecules through hydrogen bonding and ion–dipole interaction, respectively, in addition to their hydrophobic interaction with TPM dyes. The fundamental rate constants of a fading reaction in these solutions were obtained by the SESMORTAC model. Also, the effect of electric charge and substituent groups of a number of TPM dyes on their alkaline fading rate was studied. 相似文献
19.
Youming Zhang 《Journal of fluorine chemistry》2006,127(9):1222-1227
Novel artificial anionic receptors N-flurobenzoyl-N′-phenylthioureas were synthesized by simple steps in good yields. The binding properties for anions of these N-flurobenzoyl-N′-phenylthioureas and 2N-benzoyl-N′-phenyl thiourea were examined by UV-vis and 1H NMR spectroscopy. By fluorination of the benzoyl chromophore, the receptors had higher binding affinity for tested anions than the receptor 2. Especially, we studied the anion binding efficiency of the receptors 1N-(3-flurobenzoyl)-N′-phenylthiourea and 2 in dimethyl and dimethyl sulfoxide-water binary solutions in detail respectively. In pure dimethyl sulfoxide, the receptors 1 and 2 had higher binding affinity for F− over AcO−. However, as the ratio of water to dimethyl sulfoxide increases, we found the binding properties for tested anions of 1 and 2 changed in dimethyl sulfoxide-water binary solutions. The receptor 1 showed high binding affinity and selective ability for AcO− in dimethyl sulfoxide containing water with varied ratios. 相似文献
20.
Dissociation of trifluoromethanesulfonic acid in non-aqueous solvents has been investigated mainly by conductometry and compared with that of p-toluenesulfonic, methanesulfonic, fluorosulfuric and perchloric acids. The solvents used are dimethyl sulfoxide, N,N-dimethylacetamide, N,N-dimethylformamide, n-butyronitrile, propylene carbonate, acetonitrile, nitromethane, methyl isobutyl ketone and acetic acid. Trifluoromethanesulfonic acid is completely dissociated in rather basic solvents such as dimethyl sulfoxide, dimethylacetamide and dimethylformamide, while it is associated to some extent in the other solvents, especially in methyl isobutyl ketone and acetic acid. The strength of trifluoromethanesulfonic acid is almost the same as that of perchloric acid in all the solvents. Dissociation constants of the other acids are also obtained. 相似文献