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1.
M. M. Mato M. Illobre P. V. Verdes J. L. Legido E. Jiménez M. I. Paz Andrade 《Journal of Thermal Analysis and Calorimetry》2007,88(2):607-611
Excess molar enthalpies
of the ternary mixture {x
1
tert-butyl methyl ether (MTBE)+x
2
ethanol+(1–x
1–x
2) octane} and the involved
binary mixture {x ethanol+(1–x) octane} have been measured at 298.15 K and atmospheric
pressure, over the whole composition range, using a Calvet microcalorimeter.
The results were fitted by means of different variable degree polynomials. 相似文献
2.
M. M. Mato P. V. Verdes M. Illobre J. L. Legido M. I. Paz Andrade 《Journal of Thermal Analysis and Calorimetry》2008,92(1):185-189
Excess molar enthalpies, measured at 298.15 K in a Calvet microcalorimeter, are reported for {x 1 tert-butyl methyl ether (MTBE)+x 2ethanol (EtOH)+(1?x 1?x 2)heptane}. Smooth representations of the results are presented and used to construct contant excess molar enthalpy contours on Roozeboom diagrams. 相似文献
3.
P. V. Verdes M. M. Mato J. L. Legido E. Jiménez M. I. Paz Andrade 《Journal of Thermal Analysis and Calorimetry》2007,88(2):583-586
Excess molar enthalpies, H
E,
for the binary mixtures {p-xylene+(1–x) octane}, {x
p-xylene+(1–x)
diethyl carbonate}, {x octane+(1–x) diethyl carbonate} and the corresponding ternary
system {x
1
p-xylene+x
2
octane+(1–x
1–x
2) diethyl carbonate} have
been measured by using a Calvet microcalorimeter at 298.15 K under atmospheric
pressure. The experimental H
E
values are all positive for the binary and ternary mixtures over the entire
composition range. 相似文献
4.
P. V. Verdes M. M. Mato J. L. Legido E. Jiménez M. I. Paz Andrade 《Journal of Thermal Analysis and Calorimetry》2007,88(2):613-616
Excess molar enthalpies
of the ternary system {x
1
p-xylene+x
2decane+(1–x
1–x
2)diethyl
carbonate} and the involved binary mixtures {p-xylene+(1–x)decane}, {xp-xylene+(1–x)diethyl carbonate} and {xdecane+(1–x)diethyl carbonate} have been determined at the
temperature of 298.15 K and atmospheric pressure, over the whole composition
range, using a Calvet microcalorimeter. The experimental excess molar enthalpies H
m
E
are positive for all the binary systems studied over the whole composition
range. Excess molar enthalpy for the ternary system is positive as well, showing
maximum values at x
1=0, x
2=0.4920, x
3=0.5080, H
m,123
E=1524
J mol–1. 相似文献
5.
Cebreiro S. M. Illobre M. Mato M. M. Verdes V. V. Legido J. L. Paz Andrade M. I. 《Journal of Thermal Analysis and Calorimetry》2002,70(1):251-254
We have determined the excess molar enthalpies H
m
E at 298.15 K and normal atmospheric pressure for the binary mixtures containing tert-butyl methyl ether (MTBE)+(methanol, ethanol, 1-propanol, 1-pentanol) using a Calvet microcalorimeter.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
6.
M. M. Mato S. M. Cebreiro J. L. Legido M. I. Paz Andrade 《Journal of Thermal Analysis and Calorimetry》2006,84(1):279-283
Experimental
excess molar volumes for the ternary system {x1MTBE+x21-propanol+(1–x1–x2)nonane}
and the three involved binary mixtures have been determined at 298.15 K and
atmospheric pressure. Excess molar volumes were determined from the densities
of the pure liquids and mixtures, using a DMA 4500 Anton Paar densimeter.
The ternary mixture shows maximum values
around the binary mixture MTBE+nonane and minimum values for the mixture MTBE+propanol.
The ternary contribution to the excess molar volume is negative, with the
exception of a range located around the rich compositions of 1-propanol.
Several empirical equations predicting ternary mixture properties from
experimental binary mixtures have been applied. 相似文献
7.
Tie line data of {methanol + methyl tert-butyl ether + isooctane} ternary systems were obtained at T = 303.15 K, while data for {methanol + ethylbenzene + isooctane} were taken from literature. The ternary system {methanol + methyl tert-butyl ether + ethylbenzene} and {methyl tert-butyl ether + ethylbenzene + isooctane} were completely miscible. A quaternary system {methanol + ethylbenzene + isooctane + methyl tert-butyl ether} was also studied at the same temperature. In order to obtain equilibium data of the quaternary system, four quaternary sectional planes with several methyl tert-butyl ether/methanol ratios were studied. The effect of the addition of methyl tert-butyl ether on the liquid-liquid equilibrium data of {methanol + ethylbenzene + isooctane} ternary system has been investigate at the same temperature. The distribution curves for ternary and quaternary system was analysed. For the quaternary system {methanol + ethylbenzene + isooctane + methyl tert-butyl ether}, experimental data demonstrated that the distribution coefficient of ethylbenzene between the hydrocarbon and methanol phase on a methyl tert-butyl ether–free basis slightly increases with the increase of methyl tert-butyl ether/methanol ratio. Ternary experimental results were correlated with the UNIQUAC and NRTL equation. The NRTL equation is more accurate than the UNIQUAC equation for the ternary systems studied here. The equilibrium data of three ternary systems were used for determining interactions parameters for the UNIQUAC equation. The UNIQUAC equation fitted to the experimental data appeared to be more accurate than the UNIFAC method for the same quaternary system. 相似文献
8.
H.-L. Liu S.-J. Liu Z.-L. Xiao Q.-Y. Chen D.-W. Yang 《Journal of Thermal Analysis and Calorimetry》2006,85(3):541-544
Excess molar enthalpies of binary mixtures for tributyl
phosphate (TBP)+methanol/ethanol were measured with a TAM air Isothermal calorimeter
at 298.15 K and ambient. The results for xTBP+(1–x)CH3OH
are negative in the whole range of composition, while the values for xTBP+(1–x)C2H5OH
change from positive values at low x to
small negative values at high x. The experimental
results have been correlated with the Redlich–Kister polynomial. IR
spectra of the mixtures were measured to investigate the effect of hydrogen
bonding in the mixture. 相似文献
9.
Ju-Lan Zeng Sai-Bo Yu Bo Tong Li-Xian Sun Zhi-Cheng Tan Zhong Cao Dao-Wu Yang Jing-Nan Zhang 《Journal of Thermal Analysis and Calorimetry》2011,103(3):1087-1093
An N-tert-butyloxycarbonylated organic synthesis intermediate, (S)-tert-butyl 1-phenylethylcarbamate, was prepared and investigated by means of differential scanning calorimetry (DSC) and thermogravimetry
(TG). The molar heat capacities of (S)-tert-butyl 1-phenylethylcarbamate were precisely determined by means of adiabatic calorimetry over the temperature range of 80-380 K.
There was a solid–liquid phase transition exhibited during the heating process with the melting point of 359.53 K. The molar
enthalpy and entropy of this transition were determined to be 29.73 kJ mol−1 and 82.68 J K−1 mol−1 based on the experimental C
p–T curve, respectively. The thermodynamic functions, [HT0 - H298.150 H_{T}^{0} - H_{298.15}^{0} ] and [ST0 - S298.150 S_{T}^{0} - S_{298.15}^{0} ], were calculated from the heat capacity data in the temperature range of 80–380 K with an interval of 5 K. TG experiment
showed that the pyrolysis of the compound was started at the temperature of 385 K and terminated at 510 K within one step. 相似文献
10.
A gas chromatographic method has been developed for the identification and direct determination of alcohols and methyl tert-butyl ether (MTBE) in gasolines. The technique involves simultaneous injection of the gasoline without any sample preparation onto two fused silica capillary columns of differing polarities. The method permits simultaneous determinations of methanol, ethanol, 2-propanol, tert-butanol, 1-propanol, sec-butanol, 1-butanol, and MTBE. By using an automatic sampler in combination with electronic pressure programming and BASIC programming, the determinations were performed automatically and reproducibly with a relatively short analysis time. 相似文献
11.
M. M. Mato S. M. Cebreiro P. V. Verdes A. V. Pallas J. L. Legido M. I. Paz Andrade 《Journal of Thermal Analysis and Calorimetry》2005,80(2):317-321
Summary Experimental densities for the ternary mixture x1MTBE+x21-propanol+(1-x1-x2)decane and the binary mixtures xMTBE +(1-x)1-propanol and x1-propanol+(1-x)decane have been measured at 298.15 K and atmospheric pressure, using a DMA 4500 Anton Paar densimeter. Excess molar volumes were determined from the densities of the pure liquids and mixtures. Attending to the symmetry of the studied mixtures, suitable fitting equations have been used in order to correlate adequately the experimental data. For the ternary mixture, experimental data were also used to test several empirical expressions for estimating ternary properties from experimental binary results. 相似文献
12.
Ernesto C. Tuazon William P. L. Carter Sara M. Aschmann Roger Atkinson 《国际化学动力学杂志》1991,23(11):1003-1015
The products of the reaction of the hydroxyl (OH) radical with methyl tert-butyl ether (MTBE) in NOx-air systems were identified and measured by Fourier transform infrared absorption spectroscopy and gas chromatography. The products observed, and their yields, were as follows: t-butyl formate, 76 ± 7%; formaldehyde, 37%; methyl acetate, 17 ± 2%, and acetone, 2.1 ± 0.9%, where the stated error limits represent both random (two standard deviations) and estimated systematic uncertainties. These products account for ca. 95% of the MTBE carbon reacted. Infrared absorption bands which may be due to small amounts of organic nitrate formation were observed, but organic nitrate yields could not be quantified. These data allow a chemical mechanism for the reaction of MTBE with the OH radical in the presence of NOx to be formulated. 相似文献
13.
E. A. Zaburdaeva M. A. Lopatin T. I. Lopatina V. A. Dodonov 《Russian Chemical Bulletin》2008,57(2):304-308
Oxidation of fullerene C60 with the system aluminum tri-tert-butoxide-tert-butyl hydroperoxide, in which electron-excited dioxygen is generated, gave a complex mixture of fullerene oxides C60O
x
(x = 1–6). The pathways of their formation were proposed.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 296–300, February, 2008. 相似文献
14.
A. M. Sheloumov F. M. Dolgushin M. V. Kondrashov P. V. Petrovskii Kh. A. Barbakadze O. I. Lekashvili A. A. Koridze 《Russian Chemical Bulletin》2007,56(9):1757-1764
First ruthenium complexes with a ferrocene-based pincer ligand were synthesized. The cyclometallation of 1,3-bis[(di-tert-butylphosphino)methyl]ferrocene with RuCl2(DMSO)4 in 2-methoxyethanol afforded the RuCl(CO)[{2,5-(But
2PCH2)2C5H2}Fe(C5H5)](RuCl(CO)
) complex (5). Complex 5 reversibly binds CO to form the RuCl(CO)2
complex (6). The analogous reaction in the presence of NaBAr′4 (Ar′ = 3,5-(CF3)2C6H3) produced the cationic complex {Ru(CO)2
}BAr′4 (7). The structures of complexes 5 and 7 were established by single-crystal X-ray diffraction. The X-ray diffraction study revealed an agostic interaction between
one of the C-H bonds of the axial (exo-oriented with respect to the ferrocene iron atom) tert-butyl group and the Ru atom in complexes 5 and 7.
Dedicated to Academician G. A. Abakumov on the occasion of his 70th birthday.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1695–1701, September, 2007. 相似文献
15.
M. M. Mato S. M. Cebreiro P. V. Verdes J. L. Legido M. I. Paz Andrade 《Journal of Thermal Analysis and Calorimetry》2005,80(2):303-309
Experimental excess molar enthalpies and excess molar volumes of the ternary system x1MTBE+x21-propanol+(1-x1-x2) hexane and the involved binary mixtures have been determined at 298.15 K and atmospheric pressure. Excess molar enthalpies were measured using a standard Calvet microcalorimeter, and excess molar volumes were determined from the densities of the pure liquids and mixtures, using a DMA 4500 Anton Paar densimeter. The UNIFAC group contribution model (in the versions of Larsen et al., and Gmehling et al.) has been employed to estimate excess enthalpies values. Several empirical expressions for estimating ternary properties from experimental binary results were applied. 相似文献
16.
M. Rezaei-Sameti H. Iloukhani M. Rakhshi 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2010,84(12):2023-2032
In this work we used the experimental result for calculating the thermal expansion coefficients α, and their excess values
α
E
, and isothermal coefficient of pressure excess molar enthalpy and comparison the obtain results with Flory theory of liquid
mixtures for the binary mixtures {methanol, ethanol, 1-propanol and 2-butanol-chloroform} at 288.15, 293.15, 298.15, 303.15,
308.15, 313.15, 318.15, and 323.15 K. The excess thermal expansion coefficients α
E
and the isothermal coefficient of pressure excess molar enthalpy ((∂H
mE/∂P)
T,x
for binary mixtures of {methanol and ethanol + chloroform} are S-shaped and for binary mixtures of {1-propanol and 2-butanol
+ chloroform} are positive over the mole fraction. The isothermal coefficient of pressure excess molar enthalpy (∂H
mE/∂P)
T,x
, are negative over the mole fraction range for binary mixture of {1-propanol and 2-butanol + chloroform}. The calculated
values by using the Flory theory of liquid mixtures show a good agreement between the theory and experimental. 相似文献
17.
N. N. Pestereva A. Yu. Zhukova A. Ya. Neiman 《Russian Journal of Electrochemistry》2007,43(11):1305-1313
Transport numbers of oxygen ions,
, in methacomposites (1 − x)MeWO4 · xWO3, where Me = Sr and Ba and x = 0−0.55, are determined in the temperature interval 600 to 900°C by a method of the emf of an oxygen-air galvanic cell.
It is demonstrated that the region of small contents of the additive (x ≤ 0.2) is predominantly characterized by oxygen-ion conduction (
= 1), which gives way to electronic conduction (t
e = 1) at x > 0.35. It is confirmed once again that subeutectic compositions (1 − x)MeWO4 · xWO3 where Me = Sr and Ba and x = 0−0.2 belong in the class of ion-conducting methacomposites. The threshold of percolation of electronic conduction (t
e ≥ 0.5,
< 0.5) occurs at x
t ≥ 0.3. Dependences of the transport numbers of the oxygen ions on the volume ratio between components in both composites
resemble one another; specifically, the threshold composition contains nearly 20 vol % of WO3. The dramatic amplification (by 1–1.5 orders of magnitude) of the ionic conductivity in the methacomposites occurs at small
contents of tungstic oxide (x ≤ 0.01). A chemical transport removal of excess tungstic oxide, which is segregated in the form of the surface compound MeW-s,
from the surface of the MeWO4 grains destroys MeW-s, leading to a 10–15-fold drop of the ionic conductance. At x ≥ 0.05, the oxygen-ion conductance in the methacomposites is practically independent of their composition. A model for the
formation and architecture of the methacomposites is qualitatively modified. The modified model takes into account doubled
surface activity and mobility of the MeW-s phase with respect to MeWO4 and WO3.
Original Russian Text ? N.N. Pestereva, A.Yu. Zhukova, A. Ya. Neiman, 2007, published in Elektrokhimiya, 2007, Vol. 43, No.
11, pp. 1379–1386. 相似文献
18.
A sensitive LC-MS/MS assay for quantification of total and free concentrations of R- and S-warfarin in plasma was required
to support clinical studies on warfarin enantiomers. Several ultrafiltration devices were evaluated for separation of free
warfarin from plasma proteins. The highest precision and lowest non-specific binding was obtained for Centrifree ultrafiltration
devices. R- and S-warfarin were extracted from plasma (total) and ultrafiltrate (free) by liquid–liquid extraction with methyl
tert-butyl ether using d6-warfarin as internal standard. Mean extraction recovery was 68 ± 4%. The enantiomers were separated on a Chirobiotic V column
with isocratic elution using 40% methanol and 0.03% acetic acid in water. Negative mode electrospray ionisation was used for
MS/MS detection, monitoring the ion transition m/z 307/161. Calibration curves (quadratic, weighted 1/x) were fitted over the range of 20–2,000 ng/ml (r
2 ≥ 0.995) in plasma and 0.5–20 ng/ml (r
2 ≥ 0.998) in ultrafiltrate. The lower limit of quantification for R- and S-warfarin was 0.5 ng/ml in ultrafiltrate. Intra-
and interday precision (% RSD) and bias were within 10% in all cases, and matrix effects were negligible. The assay was applied
successfully to analysis of samples from clinical studies. 相似文献
19.
Ricardo K. Donato Marcelo V. Migliorini Moisés A. Benvegnú Jairton Dupont Reinaldo S. Gonçalves Henri S. Schrekker 《Journal of Solid State Electrochemistry》2007,11(11):1481-1487
The electrochemical behavior of a platinum electrode in a set of 1-alkyl ether (and 1-alkyl)-3-methylimidazolium room-temperature
ionic liquids (RTILs) 1–3 ([CxOyMim]+[Anion]− or [CxMim]+[Anion]−, where Mim = 3-methylimidazolium; CxOy = 1-alkyl ether; C7O3 = -(CH2)2O(CH2)2O(CH2)2OCH3; C3O1 = -(CH2)2OCH3; Cx = 1-alkyl; C10 = C10H21; C4 = C4H9; and ) was studied by cyclic voltammetry and electrical conductivity. This complementary set of imidazolium RTILs allowed us to
explore the effect of the imidazolium cation and the counter-ion, both of which affected the electrochemical window of these
RTILs. Various electrochemical events with low current values were observed, which diminished the electrochemical windows.
Interestingly, RTILs 2b [1-(2-methoxyethyl)-3-methylimidazolium tetrafluoroborate] and 2d [1-butyl-3-methylimidazolium tetrafluoroborate]
showed quasireversible charge transfer processes. The length of the functional group attached to the imidazolium cation was
shown to be of great influence as larger electrochemical windows, as well as lower electrical conductivities, were obtained
with the longer C7O3 and C10 functional groups. The largest electrochemical window of 2.0 V was achieved with RTIL 2c, 1-decyl-3-methylimidazolium tetrafluoroborate.
Dedicated to the memory of Prof. Francisco Nart. 相似文献
20.
P. V. Verdes M. M. Mato J. L. Legido M. I. Paz Andrade 《Journal of Thermal Analysis and Calorimetry》2008,92(1):179-183
Densities at 298.15 K and atmospheric pressure have been measured, using a DMA 4500 Anton Paar densimeter, for the ternary
mixture methyl tert-butyl ether (MTBE)+1-pentanol+nonane and for the involved binary mixture 1-pentanol+nonane. In addition, excess molar volumes
were determined from the densities of the pure liquids and mixtures. Suitable fitting equations have been used in order to
correlate adequately the excess molar volumes.
Experimental data were also used to test several empirical expressions for estimating ternary properties from experimental
binary results. 相似文献