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1.
Mohammad M. H. Bhuiyan Andrew W. Hakin Jin Lian Liu 《Journal of solution chemistry》2010,39(6):877-896
Apparent molar volumes (V
2,φ
) and heat capacities (C
p2,φ
) of glycine in known concentrations (1.0, 2.0, 4.0, 6.0, and 8.0 mol⋅kg−1) of aqueous formamide (FM), acetamide (AM), and N,N-dimethylacetamide (DMA) solutions at T=298.15 K have been calculated from relative density and specific heat capacity measurements. These measurements were completed
using a vibrating-tube flow densimeter and a Picker flow microcalorimeter, respectively. The concentration dependences of
the apparent molar data have been used to calculate standard partial molar properties. The latter values have been combined
with previously published standard partial molar volumes and heat capacities for glycine in water to calculate volumes and
heat capacities associated with the transfer of glycine from water to the investigated aqueous amide solutions, D[`(V)]2,tro\Delta\overline{V}_{\mathrm{2,tr}}^{\mathrm{o}} and D[`(C)]p2,tro\Delta\overline{C}_{p\mathrm{2,tr}}^{\mathrm{o}} respectively. Calculated values for D[`(V)]2,tro\Delta\overline{V}_{\mathrm{2,tr}}^{\mathrm{o}} and D[`(C)]p2,tro\Delta\overline{C}_{p\mathrm{2,tr}}^{\mathrm{o}} are positive for all investigated concentrations of aqueous FM and AM solutions. However, values for D[`(C)]p2,tro\Delta\overline{C}_{p\mathrm{2,tr}}^{\mathrm{o}} associated with aqueous DMA solutions are found to be negative. The reported transfer properties increase with increasing
co-solute (amide) concentration. This observation is discussed in terms of solute + co-solute interactions. The transfer properties
have also been used to estimate interaction coefficients. 相似文献
2.
Dilatometric measurements of excess molar volumes, VE and excess partial molar volumes, [`(V)] \texti\textE\overline V _{\text{i}}^{\text{E}} have been made for binary mixtures of acetonitrile with 1,2-ethanediol, 1,2-propanediol, 1,2-butanediol, 1,2-pentanediol, and 1,2-hexanediol at 20°C over the entire composition range. VE for acetonitrile + 1,2-ethanediol and 1,2-propanediol mixtures are negative over the entire range of mole fractions and positive values are obtained for all remaining mixtures. The results are explained in terms of dissociation of the self-associated 1,2-alkanediol molecules and the formation of aggregates between unlike molecules through O—H...N=C hydrogen bonding. From the experimental results, VE were calculated and correlated by Redlich–Kister type function in terms of mole fractions. The excess partial molar volumes were extrapolated to zero concentration to obtain the limiting values at infinite dilution, [`(V)] \texti\textE,o\overline V _{\text{i}}^{{\text{E,o}}}
. 相似文献
3.
The molar enthalpies of solution of 2-aminopyridine at various molalities were measured at T=298.15 K in double-distilled water by means of an isoperibol solution-reaction calorimeter. According to Pitzer’s theory,
the molar enthalpy of solution of the title compound at infinite dilution was calculated to be DsolHm¥ = 14.34 kJ·mol-1\Delta_{\mathrm{sol}}H_{\mathrm{m}}^{\infty} = 14.34~\mbox{kJ}\cdot\mbox{mol}^{-1}, and Pitzer’s ion interaction parameters bMX(0)L, bMX(1)L\beta_{\mathrm{MX}}^{(0)L}, \beta_{\mathrm{MX}}^{(1)L}, and CMXfLC_{\mathrm{MX}}^{\phi L} were obtained. Values of the relative apparent molar enthalpies (
φ
L) and relative partial molar enthalpies of the compound ([`(L)]2)\bar{L}_{2}) were derived from the experimental enthalpies of solution of the compound. The standard molar enthalpy of formation of the
cation C5H7N2 +\mathrm{C}_{5}\mathrm{H}_{7}\mathrm{N}_{2}^{ +} in aqueous solution was calculated to be DfHmo(C5H7N2+,aq)=-(2.096±0.801) kJ·mol-1\Delta_{\mathrm{f}}H_{\mathrm{m}}^{\mathrm{o}}(\mathrm{C}_{5}\mathrm{H}_{7}\mathrm{N}_{2}^{+},\mbox{aq})=-(2.096\pm 0.801)~\mbox{kJ}\cdot\mbox{mol}^{-1}. 相似文献
4.
Yameeka Chhikara J. S. Yadav Dimple Sharma V. K. Sharma 《Journal of solution chemistry》2011,40(10):1769-1783
Densities, ρ
123, and speeds of sound, u
123, of 1-methyl pyrrolidin-2-one (1) + benzene or methyl benzene or cyclohexane (2) + propan-2-ol (3) ternary mixtures have
been measured over the entire composition range at 308.15 K and atmospheric pressure. The resulting ρ
123 and V123EV_{123}^{\mathrm{E}} data were utilized to predict excess isentropic compressibilities, (kSE)123(\kappa_{S}^{\mathrm{E}})_{123}, of the studied (1+2+3) mixtures. The observed V123EV_{123}^{\mathrm{E}} and (kSE)123(\kappa_{S}^{\mathrm{E}})_{123} data have been analyzed in terms of Graph theory (which involved the topology of a molecule). It has been observed that V123EV_{123}^{\mathrm{E}} and (kSE)123(\kappa_{S}^{\mathrm{E}})_{123} values determined by Graph theory compare well with their corresponding experimental values. 相似文献
5.
V. K. Sharma Sunil K. Jangra Neeti Saini Jaibir S. Yadav Dimple Sharma 《Journal of solution chemistry》2011,40(9):1563-1581
Excess molar volumes, V
E, excess molar enthalpies, H
E, speeds of sound, u, and vapor-liquid equilibrium data of 1,4-dioxane (1) + aniline or N-methyl aniline or o-toluidine (2) binary mixtures have been measured as a function of composition at 308.15 K. Isentropic compressibility changes
that occur for mixing, kSE\kappa_{S}^{\mathrm{E}}, and excess Gibb’s energies, G
E, have been determined by employing speeds of sound and vapor-liquid equilibrium data. The VE, HE,kSEV^{\mathrm{E}}, H^{\mathrm{E}},\kappa_{S}^{\mathrm{E}} and G
E values have been estimated by (i) graph theory and (ii) the Prigonone-Flory-Patterson theory (PFP). It was observed that
values of VE, HE,kSEV^{\mathrm{E}}, H^{\mathrm{E}},\kappa_{S}^{\mathrm{E}} and G
E predicted by graph theory compare well, relative to the PFP theory, with their corresponding experimental values. 相似文献
6.
Densities, ??, and viscosities, ??, of binary mixtures of 2-methyl-2-propanol with acetone (AC), ethyl methyl ketone (EMK) and acetophenone (AP), including those of the pure liquids, were measured over the entire composition range at 298.15, 303.15 and 308.15?K. From these experimental data, the excess molar volume $V_{\mathrm{m}}^{\mathrm{E}}$ , deviation in viscosity ????, partial and apparent molar volumes ( $\overline{V}_{\mathrm{m},1}^{\,\circ }$ , $\overline{V}_{\mathrm{m},2}^{\,\circ }$ , $\overline{V}_{\phi ,1}^{\,\circ}$ and $\overline{V}_{\phi,2}^{\,\circ} $ ), and their excess values ( $\overline{V}_{\mathrm{m},1}^{\,\circ \mathrm{E}}$ , $\overline{V}_{\mathrm{m,2}}^{\,\circ \mathrm{ E}}$ , $\overline {V}_{\phi \mathrm{,1}}^{\,\circ \mathrm{ E}}$ and $\overline{V}_{\phi \mathrm{,2}}^{\,\circ \mathrm{ E}}$ ) of the components at infinite dilution were calculated. The interaction between the component molecules follows the order of AP > AC > EMK. 相似文献
7.
Iván Alonso Ismael Mozo Isaías García De La Fuente Juan Antonio González José Carlos Cobos 《Journal of solution chemistry》2011,40(12):2057-2071
Densities, ρ, and speeds of sound, u, of 2-heptanone + aniline + N-methylaniline or + pyridine systems have been measured at (293.15, 298.15 and 303.15) K and atmospheric pressure using a
vibrating tube densimeter and sound analyzer. The ρ and u values were used to calculate excess molar volumes, V
E, and the excess functions at 298.15 K for the speed of sound, u
E, the thermal expansion coefficient, apE\alpha_{p}^{\mathrm{E}}, and for the isentropic compressibility, kSE\kappa_{\mathrm{S}}^{\mathrm{E}}. V
E and kSE\kappa_{\mathrm{S}}^{\mathrm{E}} are both negative and increase in the sequence: aniline <N-methylaniline < pyridine. In contrast, u
E is positive and changes in the opposite way. The data suggest the existence of interactions between unlike molecules, which
are much weaker in the pyridine solution. Aromatic amine–alkanone interactions are stronger in mixtures with acetone. The
linear dependence of Rao’s constant with concentration reveals that there is no complex formation in the investigated systems. 相似文献
8.
Sunil K. Jangra Neeti Saini J. S. Yadav Dimple Sharma V. K. Sharma 《Journal of solution chemistry》2011,40(6):1055-1066
Excess molar volumes, V123EV_{123}^{\mathrm{E}}, of 1,3-dioxolane or 1,4-dioxane (1) + aniline (2) + benzene or toluene (3) ternary mixtures have been determined over the
entire mole fraction range at 308.15 K. V123EV_{123}^{\mathrm{E}} data have been fitted to the Redlich-Kister equation to evaluate ternary adjustable parameters and standard deviations. The
observed V123EV_{123}^{\mathrm{E}} data have been analyzed in terms of (i) Graph theory, (ii) Prigogine-Flory-Patterson theory, and (iii) Sanchez and Lacombe
theory. It has been observed that V123EV_{123}^{\mathrm{E}} values predicted by Graph theory compare well with the corresponding experimental values. 相似文献
9.
Shoichi Okouchi Pariya Thanatuksorn Shiego Ikeda Hisashi Uedaira 《Journal of solution chemistry》2011,40(5):775-785
The 17O-NMR spin-lattice relaxation times (T
1) of water molecules in aqueous solutions of n-alkylsulfonate (C1 to C6) and arylsulfonic anions were determined as a function of concentration at 298 K. Values of the dynamic hydration number,
(S-) = nh - (tc- /tc0 - 1)(\mathrm{S}^{-}) = n_{\mathrm{h}}^{ -} (\tau_{\mathrm{c}}^{-} /\tau_{\mathrm{c}}^{0} - 1), were determined from the concentration dependence of T
1. The ratios (tc -/tc0\tau_{\mathrm{c}}^{ -}/\tau_{\mathrm{c}}^{0}) of the rotational correlation times (tc -\tau_{\mathrm{c}}^{ -} ) of the water molecules around each sulfonate anion in the aqueous solutions to the rotational correlation time of pure water
(tc0\tau_{\mathrm{c}}^{0}) were obtained from the n
DHN(S−) and the hydration number (nh -n_{\mathrm{h}}^{ -} ) results, which was calculated from the water accessible surface area (ASA) of the solute molecule. The tc -/tc0\tau_{\mathrm{c}}^{ -}/\tau_{\mathrm{c}}^{0} values for alkylsulfonate anions increase with increasing ASA in the homologous-series range of C1 to C4, but then become approximately constant. This result shows that the water structures of hydrophobic hydration near large
size alkyl groups are less ordered. The rotational motions of water molecules around an aromatic group are faster than those
around an n-alkyl group with the same ASA. That is, the number of water–water hydrogen bonds in the hydration water of aromatic groups
is smaller in comparison with the hydration water of an n-alkyl group having the same ASA. Hydrophobic hydration is strongly disturbed by a sulfonate group, which acts as a water
structure breaker. The disturbance effect decreases in the following order: $\mbox{--} \mathrm{SO}_{3}^{-} > \mbox{--} \mathrm{NH}_{3}^{ +} > \mathrm{OH}> \mathrm{NH}_{2}$\mbox{--} \mathrm{SO}_{3}^{-} > \mbox{--} \mathrm{NH}_{3}^{ +} > \mathrm{OH}> \mathrm{NH}_{2}. The partial molar volumes and viscosity B
V
coefficients for alkylsulfonate anions are linearly dependent on their n
DHN(S−) values. 相似文献
10.
Nikos G. Tsierkezos Athanassios I. Philippopoulos Uwe Ritter 《Journal of solution chemistry》2009,38(12):1536-1557
The molar conductivities (Λ) of solutions of bis(2,2′-bipyridine)bis(thiocyanate)chromium(III) triiodide [CrIII(bipy)2(SCN)2]I3 (where bipy denotes 2,2′-bipyridine, C10H8N2), [
_3^-\mathrm{A}^{+}\mathrm{I}_{3}^{-}
], were measured in acetonitrile (ACN) at the temperatures 294.15, 299.15, and 305.15 K. In addition, cyclic voltammograms
(CVs) of [
A+I3-\mathrm{A}^{+}\mathrm{I}_{3}^{-}
] were recorded on platinum, gold, and glassy carbon working electrodes in ACN, using n-tetrabutylammonium hexafluorophosphate (NBu4PF6) as the supporting electrolyte, at scan rates (v) ranging from 0.05 to 0.12 V⋅s−1. Furthermore, electrochemical impedance spectroscopic (EIS) measurements were carried out in the frequency range 50 Hz<f<50 kHz using these three working electrodes. The measured molar conductivities (Λ) demonstrate that [
A+I3-\mathrm{A}^{+}\mathrm{I}_{3}^{-}
] behaves as uni-univalent electrolyte in ACN over the investigated temperature range. The Λ values were analyzed by means of the Lee-Wheaton conductivity equation in order to estimate the limiting molar conductivities (Λ
o), as well as the thermodynamic association constants (K
A), at each experimental temperature for formation of [A+
I3-\mathrm{I}_{3}^{-}
] ion-pairs. The limiting ionic conductivities (
l±o\lambda_{\pm}^{\mathrm{o}}
), the diffusion coefficients at infinite dilution (D
±), as well as the Stokes’ radii (r
St) were determined for both A+ and
I3-\mathrm{I}_{3}^{-}
ions. The thermodynamic parameters for the ionic association process, i.e. the Gibbs energy (
DGAo\Delta G_{\mathrm{A}}^{\mathrm{o}}
), enthalpy (
DHAo\Delta H_{\mathrm{A}}^{\mathrm{o}}
), and entropy (
DSAo\Delta S_{\mathrm{A}}^{\mathrm{o}}
), were also determined. The mobility and diffusivity of the A+ ion increase linearly with increasing temperature because the solvent medium becomes less viscous as the temperature increases.
The K
A values indicate that significant ion association occurs that is not influenced by temperature changes. The ion-pair formation
process is exothermic (
DHAo < 0\Delta H_{\mathrm{A}}^{\mathrm{o}}<0
), leading to the generation of additional entropy (
$\Delta S_{\mathrm{A}}^{\mathrm{o}}>0$\Delta S_{\mathrm{A}}^{\mathrm{o}}>0
). As a result, the Gibbs energy
DGAo\Delta G_{\mathrm{A}}^{\mathrm{o}}
is negative (
DGAo < 0\Delta G_{\mathrm{A}}^{\mathrm{o}}<0
) and the formation of
[A+I3-][\mathrm{A}^{+}\mathrm{I}_{3}^{-}]
becomes favorable. CV studies on
[A+I3-][\mathrm{A}^{+}\mathrm{I}_{3}^{-}]
solutions indicated that the redox pair Cr3+/2+ appears to be quasi-reversible on a glassy carbon electrode but is completely irreversible on platinum and gold electrodes.
EIS experiments confirm that, among these three electrodes, the glassy carbon working electrode has the smallest resistance
to electron transfer. 相似文献
11.
Densities, viscosities, and refractive indices of three amino acids (glycine, L-alanine, and L-valine) in aqueous solutions
of an ionic liquid, 1-propyl-3-methylimidazolium bromide, have been measured at 298.15 K. These data have been used to calculate
apparent molar volumes (V
φ
), viscosity B-coefficients, and molar refractions of these mixtures. The standard partial molar volumes (Vf0V_{\phi}^{0}) and standard partial molar volumes of transfer (DtrVf0\Delta_{\mathrm{tr}}V_{\phi}^{0}) have been determined for these amino acid solutions from these density data. The resulting values of Vf0V_{\phi}^{0} and DtrVf0\Delta_{\mathrm{tr}}V_{\phi}^{0} for transfer of amino acids from water to aqueous ionic liquid solutions have been interpreted in terms of solute + solvent
interactions. These data also indicate that hydrophobic interactions predominate in L-alanine and L-valine solutions. Linear
correlations were found for both Vf0V_{\phi}^{0} and the viscosity B-coefficient with the number of carbon atoms in the alkyl chain of the amino acids, and have been used to estimate the contribution
of the charged end groups (NH3+\mathrm{NH}_{3}^{+}, COO−), the CH2 group, and other alkyl chains of the amino acids. The viscosity and molar refractivity results have been used to confirm
the conclusions obtained from volumetric properties. 相似文献
12.
Ramzi Zarrougui Mahmoud Dhahbi Daniel Lemordant 《Journal of solution chemistry》2010,39(10):1531-1548
The densities of binary mixtures of ethylammonium nitrate (EAN) ionic liquid (IL) and γ-butyrolactone (BL) have been measured over the entire range of concentrations at 293.15, 298.15, 303.15, 308.15, 313.15 and
318.15 K and under ambient pressure. Experimental densities were used to calculate excess molar volumes VmEV_{m}^{\mathrm{E}}, isobaric and excess isobaric expansion coefficients α and α
E. The excess molar volumes have both negative and positive values, while the excess isobaric expansion coefficients are negative
over the entire composition range. The VmEV_{m}^{\mathrm{E}} values have been fitted to the Redlich-Kister polynomial equation, and other volumetric properties such as the partial molar
volumes V
mi
, the excess partial molar volume VEmiV^{\mathrm{E}}_{mi} and the partial molar volumes at infinite dilution V¥miV^{\infty}_{mi} were calculated. The results have been interpreted in terms of dipole-dipole interactions, hydrogen bonds formation and structural
factors of these mixtures. The FT-Raman spectroscopy study of the intensity variations of some characteristic bands such as
the C=O stretching band at 1763 cm−1, C–O symmetric stretching band at 932 cm−1 and C–C stretching band at 872 cm−1 of BL has been undertaken. The solvation phenomenon is evidenced by the modifications of these band intensities due to the
presence of the IL ions. Moreover, the Raman spectroscopy corroborates the volumetric study. The average number of BL molecules
in the primary solvation shell of the ethylammonium cation lies between 3 and 4 depending on the temperature. 相似文献
13.
Ponnusamy Sami Thangarajan Durai Anand Mariappan Premanathan Kasi Rajasekaran 《Transition Metal Chemistry》2010,35(8):1019-1025
Glutathione (GSH) undergoes facile electron transfer with vanadium(V)-substituted Keggin-type heteropolyoxometalates,
[ \textPV\textV \textW 1 1 \textO 4 0 ] 4 - [ {\text{PV}}^{\text{V}} {\text{W}}_{ 1 1} {\text{O}}_{ 4 0} ]^{{ 4 { - }}} (HPA1) and
[ \textPV\textV \textV\textV \textW 1 0 \textO 4 0 ] 5 - [ {\text{PV}}^{\text{V}} {\text{V}}^{\text{V}} {\text{W}}_{ 1 0} {\text{O}}_{ 4 0} ]^{{ 5 { - }}} (HPA2). The kinetics of these reactions have been investigated in phthalate buffers spectrophotometrically at 25 °C in aqueous
medium. One mole of HPA1 consumes one mole of GSH and the product is the one-electron reduced heteropoly blue,
[ \textPV\textIV \textW 1 1 \textO 40 ] 5- [ {\text{PV}}^{\text{IV}} {\text{W}}_{ 1 1} {\text{O}}_{ 40} ]^{ 5- } . But in the GSH-HPA2 reaction, one mole of HPA2 consumes two moles of GSH and gives the two-electron reduced heteropoly blue
[ \textPV\textIV \textV\textIV \textW 10 \textO 40 ] 7- [ {\text{PV}}^{\text{IV}} {\text{V}}^{\text{IV}} {\text{W}}_{ 10} {\text{O}}_{ 40} ]^{ 7- } . Both reactions show overall third-order kinetics. At constant pH, the order with respect to both [HPA] species is one and
order with respect to [GSH] is two. At constant [GSH], the rate shows inverse dependence on [H+], suggesting participation of the deprotonated thiol group of GSH in the reaction. A suitable mechanism has been proposed
and a rate law for the title reaction is derived. The antimicrobial activities of HPA1, HPA2 and
[ \textPV\textV \textV\textV \textV\textV \textW 9 \textO 4 0 ] 6 - [ {\text{PV}}^{\text{V}} {\text{V}}^{\text{V}} {\text{V}}^{\text{V}} {\text{W}}_{ 9} {\text{O}}_{ 4 0} ]^{{ 6 { - }}} (HPA3) against MRSA were tested in vitro in combination with vancomycin and penicillin G. The HPAs sensitize MRSA towards
penicillin G. 相似文献
14.
Ultrasound speeds in 31 aqueous binary mixtures of 2-(ethylamino)ethanol (EEA) were experimentally determined over the entire
composition range at 283.15, 288.15 and 303.15 K. Isentropic compressibilities, κ
S
, were calculated by combining the ultrasound speed with density data. Excess molar isentropic compressions, KS,mEK_{S,\mathrm{m}}^{\mathrm{E}}, referred to a thermodynamically-defined ideal liquid mixture, were estimated. Excess partial molar isentropic compressions,
KS,iEK_{S,i}^{\mathrm{E}}, of both components and their respective limits at infinite dilution, KS,iE,¥K_{S,i}^{\mathrm{E,}\infty}, were analytically obtained using Redlich-Kister type equations. The temperature and composition dependences of KS,iEK_{S,i}^{\mathrm{E}} were analyzed, especially in the water and EEA rich regions. The present KS,iE,¥K_{S,i}^{\mathrm{E,}\infty} values are compared with those for water + 2-diethylaminoethanol (DEEA) and water + diethylamine (DEA) mixtures, as a function
of temperature. Although the KS,2E,¥K_{S,2}^{\mathrm{E,}\infty} values for EEA and DEEA increase with temperature, the opposite trend is observed for DEA. Results for aqueous EEA and aqueous
DEEA seem to support the idea that the driving force for hydrophobic hydration relies on solute-solvent hydrophilic interaction
rather than on enhancing the water structure. On the other hand, different temperature dependent behavior is observed for
the differential volumetric properties KS,iE,¥K_{S,i}^{\mathrm{E,}\infty} and limiting excess partial molar isobaric expansion, EP,iE,¥E_{P,i}^{\mathrm{E,}\infty}, which are attributed to the different sensitivity of these properties to hydration. 相似文献
15.
Speeds of sound have been measured in dipropylene glycol monopropyl ether mixtures with methanol, 1-propanol, 1-pentanol,
and 1-heptanol as a function of composition at 288.15, 298.15, and 308.15 K and atmospheric pressure. Measurements of viscosity
at 298.15 K and atmospheric pressure have also been made for the same mixtures over the whole composition range. The speeds
of sound were combined with our previous densitity results to obtain the isentropic compressibility κ
S
. The molar volumes were multiplied by the isentropic compressibilities to obtain estimates of K
S,m
and its excess counterparts KS,mEK_{S,m}^{\mathrm{E}}. The KS,mEK_{S,m}^{\mathrm{E}} values are negative over the entire range of composition for all mixtures. Deviations in viscosity η from the mixing relation ∑x
i
ln η
i
and excess Gibbs energies of activation for viscous flow ΔG
∗E have been derived for all of these systems. Also, from the speed of sound results, the apparent molar compressibilities [`(K)]f,i0\overline{K}_{\phi ,i}^{0} of the components have been calculated at infinite dilution. The variations of these properties with the composition, temperature
and the number of carbon atoms in the alcohol molecule are discussed in terms of molecular interactions. The experimental
results have also been discussed on the basis of IR measurements. 相似文献
16.
Anil Kumar Nain 《Journal of solution chemistry》2007,36(4):497-516
The densities of binary mixtures of formamide (FA) with 1-butanol, 2-butanol, 1,3-butanediol, and 1,4-butanediol, including
those of the pure liquids, over the entire composition range were measured at temperatures (293.15, 298.15, 303.15, 308.15,
313.15 and 318.15) K and atmospheric pressure. From the experimental data, the excess molar volume, V
m
E, partial molar volumes, and , at infinite dilution, and excess partial molar volumes, and , at infinite dilution were calculated. The variation of these parameters with composition and temperature of the mixtures
are discussed in terms of molecular interactions in these mixtures. The partial molar expansivities, and , at infinite dilution and excess partial molar expansivities, and , at infinite dilution were also calculated. The V
m
E values were found to be positive for all the mixtures at each temperature studied, except for FA + 1-butanol which exhibits
a sigmoid trend wherein V
m
E values change sign from positive to negative as the concentration of FA in the mixture is increased. The V
m
E values for these mixtures follow the order: 1-butanol < 2-butanol < 1,3-butanediol < 1,4-butanediol. It is observed that
the V
m
E values depend upon the number and position of hydroxyl groups in these alkanol molecules. 相似文献
17.
Donald A. Palmer Pascale Bénézeth Caibin Xiao David J. Wesolowski Lawrence M. Anovitz 《Journal of solution chemistry》2011,40(4):680-702
Results of solubility experiments involving crystalline nickel oxide (bunsenite) in aqueous solutions are reported as functions
of temperature (0 to 350 °C) and pH at pressures slightly exceeding (with one exception) saturation vapor pressure. These
experiments were carried out in either flow-through reactors or a hydrogen-electrode concentration cell for mildly acidic
to near neutral pH solutions. The results were treated successfully with a thermodynamic model incorporating only the unhydrolyzed
aqueous nickel species (viz., Ni2+) and the neutrally charged hydrolyzed species (viz., Ni(OH)20)\mathrm{Ni(OH)}_{2}^{0}). The thermodynamic quantities obtained at 25 °C and infinite dilution are, with 2σ uncertainties:
log10Ks0o = (12.40 ±0.29),\varDeltarGmo = -(70. 8 ±1.7)\log_{10}K_{\mathrm{s0}}^{\mathrm{o}} = (12.40 \pm 0.29),\varDelta_{\mathrm{r}}G_{m}^{\mathrm{o}} = -(70. 8 \pm 1.7) kJ⋅mol−1;
\varDeltarHmo = -(105.6 ±1.3)\varDelta_{\mathrm{r}}H_{m}^{\mathrm{o}} = -(105.6 \pm 1.3) kJ⋅mol−1;
\varDeltarSmo = -(116.6 ±3.2)\varDelta_{\mathrm{r}}S_{m}^{\mathrm{o}} =-(116.6 \pm 3.2) J⋅K−1⋅mol−1;
\varDeltarCp,mo = (0 ±13)\varDelta_{\mathrm{r}}C_{p,m}^{\mathrm{o}} = (0 \pm 13) J⋅K−1⋅mol−1; and log10Ks2o = -(8.76 ±0.15)\log_{10}K_{\mathrm{s2}}^{\mathrm{o}} = -(8.76 \pm 0.15);
\varDeltarGmo = (50.0 ±1.7)\varDelta_{\mathrm{r}}G_{m}^{\mathrm{o}} = (50.0 \pm 1.7) kJ⋅mol−1;
\varDeltarHmo = (17.7 ±1.7)\varDelta_{\mathrm{r}}H_{m}^{\mathrm{o}} = (17.7 \pm 1.7) kJ⋅mol−1;
\varDeltarSmo = -(108±7)\varDelta_{\mathrm{r}}S_{m}^{\mathrm{o}} = -(108\pm 7) J⋅K−1⋅mol−1;
\varDeltarCp,mo = -(108 ±3)\varDelta_{\mathrm{r}}C_{p,m}^{\mathrm{o}} = -(108 \pm 3) J⋅K−1⋅mol−1. These results are internally consistent, but the latter set differs from those gleaned from previous studies recorded in
the literature. The corresponding thermodynamic quantities for the formation of Ni2+ and Ni(OH)20\mathrm{Ni(OH)}_{2}^{0} are also estimated. Moreover, the Ni(OH)3 -\mathrm{Ni(OH)}_{3}^{ -} anion was never observed, even in relatively strong basic solutions (mOH - = 0.1m_{\mathrm{OH}^{ -}} = 0.1 mol⋅kg−1), contrary to the conclusions drawn from all but one previous study. 相似文献
18.
Apparent molar volumes V
φ,B of n-propylamine, n-butylamine, di-n-propylamine, di-n-butylamine, triethylamine, tri-n-propylamine, and tri-n-butylamine in 1,4-dioxane and in oxolane (tetrahydrofuran) have been determined at 303.15 K using a high-precision Anton
Paar vibrating-tube densimeter (model DMA 60/602). The limiting partial molar volumes
and limiting excess partial molar volumes
are analyzed and interpreted in terms of solute-solvent interactions and structural effects of the molecules.
Analyses were made of the contributions of specific interactions to the partial molar volumes of these primary, secondary
and tertiary amines in 1,4-dioxane and oxolane using the Terasawa model, scaled particle theory (SPT) and hard-sphere theory
(HST). The ERAS model has also been applied to estimate the apparent molar volumes and excess apparent molar volumes of alkylamine
solutions in 1,4-dioxane and oxolane. 相似文献
19.
20.
Ricardo Picciochi Hermínio P. Diogo Manuel E. Minas da Piedade 《Journal of Thermal Analysis and Calorimetry》2010,100(2):391-401
Combustion calorimetry, Calvet-drop sublimation calorimetry, and the Knudsen effusion method were used to determine the standard
(p
o = 0.1 MPa) molar enthalpies of formation of monoclinic (form I) and gaseous paracetamol, at T = 298.15 K:
\Updelta\textf H\textm\texto ( \textC 8 \textH 9 \textO 2 \textN,\text cr I ) = - ( 4 10.4 ±1. 3)\text kJ \textmol - 1 \Updelta_{\text{f}} H_{\text{m}}^{\text{o}} \left( {{\text{C}}_{ 8} {\text{H}}_{ 9} {\text{O}}_{ 2} {\text{N}},{\text{ cr I}}} \right) = - ( 4 10.4 \pm 1. 3){\text{ kJ}}\;{\text{mol}}^{ - 1} and
\Updelta\textf H\textm\texto ( \textC 8 \textH 9 \textO 2 \textN,\text g ) = - ( 2 80.5 ±1. 9)\text kJ \textmol - 1 . \Updelta_{\text{f}} H_{\text{m}}^{\text{o}} \left( {{\text{C}}_{ 8} {\text{H}}_{ 9} {\text{O}}_{ 2} {\text{N}},{\text{ g}}} \right) = - ( 2 80.5 \pm 1. 9){\text{ kJ}}\;{\text{mol}}^{ - 1} . From the obtained
\Updelta\textf H\textm\texto ( \textC 8 \textH 9 \textO 2 \textN,\text cr I ) \Updelta_{\text{f}} H_{\text{m}}^{\text{o}} \left( {{\text{C}}_{ 8} {\text{H}}_{ 9} {\text{O}}_{ 2} {\text{N}},{\text{ cr I}}} \right) value and published data, it was also possible to derive the standard molar enthalpies of formation of the two other known
polymorphs of paracetamol (forms II and III), at 298.15 K:
\Updelta\textf H\textm\texto ( \textC 8 \textH 9 \textO 2 \textN,\text crII ) = - ( 40 8.4 ±1. 3)\text kJ \textmol - 1 \Updelta_{\text{f}} H_{\text{m}}^{\text{o}} \left( {{\text{C}}_{ 8} {\text{H}}_{ 9} {\text{O}}_{ 2} {\text{N}},{\text{ crII}}} \right) = - ( 40 8.4 \pm 1. 3){\text{ kJ}}\;{\text{mol}}^{ - 1} and
\Updelta\textf H\textm\texto ( \textC 8 \textH 9 \textO 2 \textN,\text crIII ) = - ( 40 7.4 ±1. 3)\text kJ \textmol - 1 . \Updelta_{\text{f}} H_{\text{m}}^{\text{o}} \left( {{\text{C}}_{ 8} {\text{H}}_{ 9} {\text{O}}_{ 2} {\text{N}},{\text{ crIII}}} \right) = - ( 40 7.4 \pm 1. 3){\text{ kJ}}\;{\text{mol}}^{ - 1} . The proposed
\Updelta\textf H\textm\texto ( \textC 8 \textH 9 \textO 2 \textN,\text g ) \Updelta_{\text{f}} H_{\text{m}}^{\text{o}} \left( {{\text{C}}_{ 8} {\text{H}}_{ 9} {\text{O}}_{ 2} {\text{N}},{\text{ g}}} \right) value, together with the experimental enthalpies of formation of acetophenone and 4′-hydroxyacetophenone, taken from the
literature, and a re-evaluated enthalpy of formation of acetanilide,
\Updelta\textf H\textm\texto ( \textC 8 \textH 9 \textON,\text g ) = - ( 10 9. 2 ± 2. 2)\text kJ \textmol - 1 , \Updelta_{\text{f}} H_{\text{m}}^{\text{o}} \left( {{\text{C}}_{ 8} {\text{H}}_{ 9} {\text{ON}},{\text{ g}}} \right) = - ( 10 9. 2\,\pm\,2. 2){\text{ kJ}}\;{\text{mol}}^{ - 1} , were used to assess the predictions of the B3LYP/cc-pVTZ and CBS-QB3 methods for the enthalpy of a isodesmic and isogyric
reaction involving those species. This test supported the reliability of the theoretical methods, and indicated a good thermodynamic
consistency between the
\Updelta\textf H\textm\texto \Updelta_{\text{f}} H_{\text{m}}^{\text{o}} (C8H9O2N, g) value obtained in this study and the remaining experimental data used in the
\Updelta\textr H\textm\texto \Updelta_{\text{r}} H_{\text{m}}^{\text{o}} calculation. It also led to the conclusion that the presently recommended enthalpy of formation of gaseous acetanilide in
Cox and Pilcher and Pedley’s compilations should be corrected by ~20 kJ mol−1. 相似文献