Recovery of Formic Acid by Reactive Extraction Using an Environmentally-Friendly Solvent (original) (raw)
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Journal of Chemical & Engineering Data, 2010
This study aims to investigate the extraction of formic acid by a high molecular-weight aliphatic amine, tridodecylamine (TDA), and a phosphorus-bonded, oxygen-containing extractant, tributyl phosphate (TBP), dissolved in five different diluents (ethyl valerate, diethyl adipate, diethyl sebacate, 1-octanol, and heptane) each. The experiments were carried out at 298.15 K. Comparisons of the results were made using the distribution coefficient, loading factor, separation factor, and the percentage of extraction yield. The results demonstrated that combination of TDA and diethyl adipate had the greatest synergistic effects with a distribution value of 6. The maximum value of the extraction efficiency was found to be 87 % with a 1.09 mol · L -1 concentration of TDA in diethyl adipate.
ACS Omega, 2017
The distribution coefficients and selectivities required for extraction purposes were predicted with a thermodynamic equation of state for the ternary system formic acid/water/extraction solvent. These predictions were validated with experimental data from the literature and experimental data from the oxidation of biomass to formic acid process measured in this work. Extraction solvents discussed in this work are 1-butanol, 1-pentanol, 1-hexanol, 1-heptanol, 1octanol, 1-decanol, ethyl n-butyl ether, diisopropyl ether, di-nbutyl ether, benzyl formate, and heptyl formate. The considered temperature ranged from 273 to 363 K under atmospheric pressure. Perturbed-chain statistical associating fluid theory (PC-SAFT) was used for prediction purposes applying an approach as simple as possible and as complex as necessary to achieve trustworthy data for selecting the best extraction solvent. Using PC-SAFT allowed identifying 1-hexanol as the most promising solvent out of the 11 extraction agents. The predicted data were in good agreement with the experimental distribution coefficients and the selectivities, which are very sensitive to experimental uncertainties.
2019
In this study, the separation of formic acid from aqueous solutions was investigated. Liquid-liquid equilibrium (LLE) data including tie-lines was reported for water + formic acid + 2-methylpropyl ethanoate ternary mixture at (293.15 to 323.15) K and atmospheric pressure. The system shows type-I phase behavior based on Treybal’s classification because only one partially miscible binary mixture (water + 2-methylpropyl ethanoate) was observed. The composition of tie-lines was determined by cloud point method and refractive index measurements. The results show that the solubility of formic acid in the water-rich phase is more than in the solvent-rich phase. The extracting capability of the solvent was ascertained by determining the distribution coefficients and separation factors. The reliability of tie-line data was checked by Othmer–Tobias and Hand equations. The experimental data were correlated with NRTL and UNIQUAC models and the binary interaction parameters were determined. The ...
Industrial & Engineering Chemistry Research
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 energyintensive. 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).
Reactive Extraction of Formic Acid by Amberlite LA-2 Extractant
Journal of Chemical & Engineering Data, 2009
The reactive extraction of formic acid by Amberlite LA-2 dissolved in five different esters (dimethyl phthalate, dimethyl adipate, dimethyl succinate, dimethyl glutarate, diethyl carbonate), five different alcohols (isoamyl alcohol, hexan-1-ol, octan-1-ol, nonan-1-ol, decan-1-ol), and two different ketones (diisobutyl ketone (DIBK), methylisobutyl ketone (MIBK)) as diluents as well as the extraction capacity of pure diluent alone have been studied at isothermal conditions. All measurements have been carried out at 298.15 K. The comparison of physical and reactive extractions has been studied. The loading factor, T T , extraction efficiency, E, modified separation factor, S F , and distribution coefficients, K D , have been calculated. The isoamylalcohol has been found to be the most effective solvent with a maximum distribution value of 19.223. Furthermore, the linear solvation energy relationship (LSER) model equation has been obtained to calculate distribution coefficients for alcohols with an R square of 0.976.
ChemEngineering, 2019
The present work develops the basics for the isolation of lactic acid, acetic acid and formic acid from a single as well as a mixed feed stream, as is present, for example, in fermentation broth for lactic acid production. Modelling of the phase equilibria data is performed using the law of mass action and shows that the acids are extracted according to their pka value, where formic acid is preferably extracted in comparison to lactic and acetic acid. Back-extraction was performed by 1 M NaHCO3 solution and shows the same tendency regarding the pka value. Based on lactic acid, the solvent phase composition, consisting of tri-n-octylamine/1-octanol/n-undecane, was optimized in terms of the distribution coefficient. The data clearly indicate that, compared to physical extraction, mass transfer can be massively enhanced by reactive extraction. With increasing tri-n-octylamine and 1-octanol concentration, the equilibrium constant increases. However, even when mass transfer increases, tr...
Application of reactive extraction to recovery of carboxylic acids
Biotechnology and Bioprocess Engineering, 2001
Carboxylic acids are examples of compounds with wide industrial applications and high potential. This article presents the principles of reactive extraction along with the characteristics of tertiary amine extractants, while is given on considering the effect of the amine class and chain length. As such a brief overview the current research on reactive extraction, including the recovery of citric acid, selective amine-based extraction, and extractive fermentation is given. When discussing extractive fermentation, strategies for reducing solvent toxicity are also suggested based on specific examples. Finally, solvent regeneration and stripping of extracted acid are explained.
Levulinic acid (LA) can be produced from lignocellulosic materials via hydroxylation followed by an acid-catalyzed conversion of hexoses. Inorganic homogeneous catalysts are mostly used, in particular sulphuric acid, yielding a mixture of LA with sulphuric acid, formic acid (FA) and furfural. Significant attention has been paid to optimization of the yield, but purification of the LA is a challenge too. This work focuses on the separation of LA from the complex aqueous mixtures by liquid-liquid extraction. Two aqueous product feeds were considered, reflecting two different processes. One aqueous product stream contains sulphuric acid and LA, while the second product stream also contains formic FA and furfural. Furfural could be removed selectively via liquid-liquid extraction with toluene. For selective extraction of LA and FA without co-extracting sulphuric acid, 30 wt.% of trioctylphosphine oxide (TOPO) in methylisobutylketone (MIBK) was found most suitable, showing a high selectivity over sulphuric acid, and a high equilibrium partitioning of LA. When instead of MIBK, 1-octanol was applied as diluent, the co-extraction of FA was enhanced, while hexanoic acid suppressed the acid extraction. To obtain the LA pure, eventually a distillation is required, and the potential of temperature swing back extraction (TSBE) at 90 °C to pre-concentrate the acid solutions was evaluated for 30 wt.% TOPO in MIBK. This pre-concentration step increased the concentrations of LA and FA by a factor of 2.45 and 2.45 respectively, reducing the distillation reboiler duty from roughly 31.5 to 11.3 GJ per ton LA, at a cost of roughly 4.5 GJ heating duty per ton produced LA.
Extraction of carboxylic acids by amine extractants
1989
This work examines the chemistry of solvent extraction by long-chain amines for recovery of carboxylic acids from dilute aqueous solution. Long-chain amines act as complexing agents with the acid, which facilitates distribution of the acid into the organic phase. This complexation is reversible, allowing for recovery of the acid from the organic phase and regeneration of the extractant. Batch extraction experiments were performed to study the complexation of acetic, lactic, succinic, malonic, fumaric, and maleic acids with Alamine 336, an aliphatic, tertiary amine extractant, dissolved in various diluents. The diluents were selected from a variety of chemical classes, including halogenated hydrocarbons, alcohols, ketones, substituted aromatics, and alkanes. The results of batch extraction experiments were interpreted by a "chemical" model, in which stoichiometric ratios of acid and amine molecules are assumed to form complexes in the solvent phase. From fitting of the extraction data, the stoichiometry of complexes formed and the corresponding equilibrium constants were obtained. The results of the model were combined with infrared spectroscopic experiments aJld results of past studies to analyze the chemical interactions that are responsible for extraction behavior.
Removal of low molecular organic acids from aqueous solutions with reactive extraction
Polish Journal of Chemical Technology, 2013
This paper presents investigation on removal of low molecular organic acids (acetic, lactic, succinic and fumaric) from aqueous solutions with reactive extraction. The results specifi cally show that the extraction effi ciency of acids depends on the type of extractant, diluents of the organic phase and the initial pH of the aqueous phase. It is possible to separate succinic or fumaric from lactic and acetic acids with high selectivity with the use of TOA and Aliquat 336, respectively. Increasing the pH of the aqueous phase results in a reduction of fumaric acid extraction effi ciency with solvating extractants. This can be explained by the decreasing share of acidic form, whose extraction is favored by these extractants. Effi cient extraction of both fumaric acid and fumarate using Aliquat 336 can be explained by the ionic structure of the quaternary ammonium salt, capable of transporting both forms of the acid.