4 research outputs found
Solid–Liquid Equilibrium (SLE) of the <i>N</i>,<i>N</i>‑Dimethylacetamide (DMA) + MCl (M = Na, K, Rb, and Cs) + Water Ternary Systems at Multiple Temperatures
We
report herein the solid–liquid equilibria (SLE) of <i>N</i>,<i>N</i>-dimethylacetamide (DMA) + MCl (M =
Na, K, Rb, and Cs) + H<sub>2</sub>O ternary systems for the first
time. At the three given temperatures (<i>T</i> = 298.15
K, 308.15 K, and 318.15 K), the solubilities, densities, and refractive
indices for these ternary systems are determined with the mass fraction
of DMA in salt-free solvent system ranging from 0.0 to 1.0. The solubility
of salts decreases significantly with the addition of DMA, and the
salting-out ratios are calculated accordingly. The nonrandom two-liquid
(NRTL) model can effectively fit the experimental solubility. Furthermore,
to investigate the temperature effect on the SLE, the dynamic solubility
measurement system is selected to determine the solubility of the
salts in the mixed solvent (<i>w</i><sub>DMA</sub> = 0.3,
0.5, and 0.7) with the temperature continuously increased. The solubility
data at multiple temperatures are well fitted by the modified Apelblat
equation and the λ<i>h</i> equation
Measurements and Correlations of the Solid–Liquid Equilibrium of RbCl/CsCl + [C<sub><i>n</i></sub>mim]Cl (<i>n</i> = 2, 4, 6, 8) + H<sub>2</sub>O Ternary Systems at <i>T</i> = (288.15, 298.15, and 308.15) K
The
solubility, density and refractive index of RbCl/CsCl + [C<sub><i>n</i></sub>mim]Cl (<i>n</i> = 2, 4, 6, 8)
+ H<sub>2</sub>O saturated systems have been studied at <i>T</i> = (288.15, 298.15 and 308.15) K. The solubility data were correlated
by the nonrandom two-liquid (NRTL) model and an empirical equation.
Both models can qualitatively represent the equilibrium behavior.
In addition, the results denote that all the ionic liquids trigger
salting-out effects with the order: [C<sub>2</sub>mim]Cl > [C<sub>4</sub>mim]Cl > [C<sub>6</sub>mim]Cl > [C<sub>8</sub>mim]ÂCl.
The
density and refractive index of the saturated solutions were determined
for describing the relationship between the physical property and
composition of the solution
Activity Coefficients of RbF in the RbF + RbBr + H<sub>2</sub>O and RbF + RbNO<sub>3</sub> + H<sub>2</sub>O Ternary Systems Using the Potentiometric Method at 298.2 K
Thermodynamic properties of the RbF
+ RbBr + H<sub>2</sub>O and
RbF + RbNO<sub>3</sub> + H<sub>2</sub>O systems were determined by
the potentiometric method at the total ionic strengths ranging from
0.0017 to 0.7005 mol·kg<sup>–1</sup> for different ionic
strength fractions <i>y</i><sub>B</sub> of RbBr/RbNO<sub>3</sub> with <i>y</i><sub>B</sub> = 0.00, 0.30, 0.60, and
0.90, at 298.2 K. Combining the Nernst equation and Pitzer equation,
the mean ionic activity coefficients of RbF and RbBr/RbNO<sub>3</sub>, the osmotic coefficients, and the excess Gibbs energies of the
studied systems were calculated
Design of Pore Size and Functionality in Pillar-Layered Zn-Triazolate-Dicarboxylate Frameworks and Their High CO<sub>2</sub>/CH<sub>4</sub> and C2 Hydrocarbons/CH<sub>4</sub> Selectivity
In the design of new materials, those
with rare and exceptional compositional and structural features are
often highly valued and sought after. On the other hand, materials
with common and more accessible modes can often provide richer and
unsurpassed compositional and structural variety that makes them a
more suitable platform for systematically probing the composition–structure–property
correlation. We focus here on one such class of materials, pillar-layered
metal–organic frameworks (MOFs), because different pore size
and shape as well as functionality can be controlled and adjusted
by using pillars with different geometrical and chemical features.
Our approach takes advantage of the readily accessible layered Zn-1,2,4-triazolate
motif and diverse dicarboxylate ligands with variable length and functional
groups, to prepare seven Zn-triazolate-dicarboxylate pillar-layered
MOFs. Six different gases (N<sub>2</sub>, H<sub>2</sub>, CO<sub>2</sub>, C<sub>2</sub>H<sub>2</sub>, C<sub>2</sub>H<sub>4</sub>, and CH<sub>4</sub>) were used to systematically examine the dependency of gas
sorption properties on chemical and geometrical properties of those
MOFs as well as their potential applications in gas storage and separation.
All of these pillar-layered MOFs show not only remarkable CO<sub>2</sub> uptake capacity, but also high CO<sub>2</sub> over CH<sub>4</sub> and C2 hydrocarbons over CH<sub>4</sub> selectivity. An interesting
observation is that the BDC ligand (BDC = benzenedicarboxylate) led
to a material with the CO<sub>2</sub> uptake outperforming all other
metal-triazolate-dicarboxylate MOFs, even though most of them are
decorated with amino groups, generally believed to be a key factor
for high CO<sub>2</sub> uptake. Overall, the data show that the exploration
of the synergistic effect resulting from combined tuning of functional
groups and pore size may be a promising strategy to develop materials
with the optimum integration of geometrical and chemical factors for
the highest possible gas adsorption capacity and separation performance