Formic acid (FA)
is an interesting hydrogen (H
2
) and
carbon monoxide (CO) carrier that can be produced by the electrochemical
reduction of carbon dioxide (CO
2
) using renewable energy.
The separation of FA from water is challenging due to the strong (cross)association
of the components and the presence of a high boiling azeotrope. For
the separation of dilute FA solutions, liquid–liquid extraction
is preferred over conventional distillation because distilling large
amounts of water is very energy-intensive. In this study, we use 2-methyltetrahydrofuran
(2-MTHF) to extract FA from the CO
2
electrolysis process,
which typically contains <20 wt % of FA. Vapor–liquid equilibrium
(VLE) data of the binary system 2-MTHF–FA and liquid–liquid
equilibrium (LLE) data of the ternary system 2-MTHF–FA–water
are obtained. Continuous extraction and distillation experiments are
performed to test the extraction power and recovery of 2-MTHF from
the extract. The VLE and LLE data are used to design a hybrid extraction
and distillation process to produce a commercial grade product (85
wt % of FA). A detailed economic analysis of this hybrid extraction–distillation
process is presented and compared with the existing FA separation
methods. It is shown that 2-MTHF is a cost-effective solvent for FA
extraction from dilute streams (<20 wt % FA).
Isobaric vapor−liquid equilibrium data of the binary systems comprising 2-ethoxyethanol, 2-ethoxyethyl acetate, and toluene were measured using an ebulliometer. The boiling temperatures of the binary mixtures are reported for six different pressures ranging from 53.3 to 101.3 kPa. The binary system 2-ethoxyethanol−toluene shows a low-boiling azeotrope around 90 mol % toluene. A nonrandom two-liquid (NRTL) model was used to fit the binary (PTx) data. The experimental data were verified using the thermodynamic consistency tests of Redlich−Kister and Wisniak. The reported data were compared with available literature data and modeling results. The studied systems are relevant for the design of azeotropic/reactive distillation columns for the esterification of 2-ethoxyethanol and acetic acid using toluene as an entrainer.
Benzethonium chloride (BTC) has various applications in several industries. The solubility and solution thermodynamic properties of BTC were measured. The solubility of BTC in methanol, ethanol, 1-propanol, 2-propanol, 1butanol, water, dimethyl sulfoxide, acetic acid, and dimethyl formamide neat solvents and methanol + water and ethanol + water binary solvents at 298.15−318.15 K over an atmospheric pressure was measured. The solubility data of BTC is positively related to the temperature in all selected solvents. The solubility data was fitted by the Apelblat model, λh model, Yaws model, Van't Hoff equation, CNIBS/R-K model, and modified Jouyban−Acree equation. The RMSD and ARD were chosen to evaluate the fitting of each model. The dissolution thermodynamic parameters, enthalpy of the solution, entropy of the solution, and Gibbs energy of the solution were calculated. The solubility data and dissolution thermodynamic parameters of BTC will provide significant guidance for purification, crystallization, and separation in various areas.
Vapor–liquid equilibrium (VLE) data for the binary
systems
tetrahydrofuran (THF) + acetic acid (AA) and THF + trichloroethylene
(TCE) were measured under isobaric conditions using an ebulliometer.
The boiling temperatures for the systems (THF + AA/THF + TCE) are
reported for 13/15 compositions and five/six different pressures ranging
from 50.2/60.0 to 101.1/101.3 kPa, respectively. The THF + AA system
shows simple phase behavior with no azeotrope formation. The THF +
TCE system does not exhibit azeotrope formation but seems to have
a pinch point close to the pure end of TCE. The nonrandom two-liquid
(NRTL) and universal quasichemical (UNIQUAC) activity coefficient
models were used to accurately fit the binary (PTx) data. Both models were able to fit the binary VLE data satisfactorily.
However, the NRTL model was found to be slightly better than UNIQUAC
model in fitting the VLE data for both systems. The results can be
used for designing liquid–liquid extraction and distillation
processes involving mixtures of THF, AA, and TCE.
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