Extraction Of Carboxylic Acids Research Articles

Mineral Acid Co-Extraction in Reactive Extraction of Lactic Acid Using a Thymol-Menthol Deep Eutectic Solvent as a Green Modifier.

Carboxylic acids can be isolated from fermentation broths using reactive liquid-liquid extraction, offering an alternative to the environmentally harmful state-of-the-art process of precipitating calcium lactate. To enhance the sustainability of liquid-liquid extraction processes, greener solvents, such as natural deep eutectic solvents, are investigated. However, fermentation broths often exhibit pH values unsuitable for carboxylic acid extraction, which can be adjusted using mineral acids, though mineral acids may be co-extracted. In this study, we systematically examine the co-extraction of hydrochloric, nitric, sulfuric, and phosphoric acid during extraction and back-extraction of lactic acid. The solvent phase consisted of tri-n-octylamine, trioctylphosphine oxide, or tributyl phosphate diluted in a thymol-menthol deep eutectic solvent. The back-extraction was conducted using a diluent swing with p-cymene as the antisolvent and water as the receiving phase. Tri-n-octylamine showed the highest efficiency for lactic acid (up to 29.8%) but also the highest co-extraction of mineral acids (up to 50.9%). In contrast, trioctylphosphine oxide exhibited a lower but more selective lactic acid extraction (5.94%) with low mineral acids co-extraction (0.135%). Overall, the highest co-extraction was observed for phosphoric acid and the lowest for nitric acid. In conclusion, the selected solvent phase composition and mineral acid influence the co-extraction and, thus, final product purity. The successful application of the natural deep eutectic solvent as the modifier enhances the sustainability of liquid-liquid extraction processes.

Reactive extraction of pyridinedicarboxylic acid (PDCA) with tri-n-octylamine and Aliquat 336 in 1-octanol – A promising approach to access microbially produced PDCA

Pyridinedicarboxylic acids (PDCA) are analogues to terephthalic acid and promising molecules for the production of bio-based plastics. Previous work achieved the microbial production of PDCAs from the renewable resource lignin but an efficient and low cost method to recover PDCA from fermentation broth is still missing. Reactive extraction is commonly applied for the extraction of carboxylic acids from aqueous phase. In this study, we investigate reactive extraction of PDCA with the two extractants tri-n-octylamine (TOA) and Aliquat 336 in the diluent 1-octanol. The extraction and re-extraction were optimized with 2,5-PDCA in an aqueous solution leading to up to 98 % extraction for both extractants. Re-extraction by pH swing resulted in > 95 % re-extracted 2,5-PDCA. A scale-up in liquid–liquid centrifuges enabled continuous extraction and re-extraction in liter scale with a yield of 95 %. A concentration factor of 3.6 was achieved and the organic phase was recycled. The approach also showed transferability to the processing of complex fermentation solution. 2,4-PDCA, microbially produced in a bioprocess, could be recovered by 65 % in one single extraction and re-extraction step from biomass-free fermentation broth.

Extraction of Carboxylic Acids from Anaerobic Fermentation Processes by the Anion Exchange Resin Amberlite IRA-400(Cl)

This work describes a methodology for the valorization of non-food biomass for the production of biosourced molecules via the production of biohydrogen and metabolites of fermentations such as volatile fatty acids. The commercial anion exchange resin Amberlite IRA-400(Cl) was chosen for the extraction of carboxylic acids. Different operating conditions were set up namely the amount of resin to be used, activation methods, pH and their effects on the extraction capacity of the solvent.

N-[tris(hydroxymethyl)methyl]-3-aminopropanesulfonic acid (TAPS) effect on the separation of carboxylic acids (acetic acid, propionic acid, or lactic acid) from their aqueous solutions using methyl isobutyl ketone as extraction solvent

This study focusses on N-[tris(hydroxymethyl)methyl]-3-aminopropanesulfonic acid (TAPS) biological buffer effect on the separation of three carboxylic acids (acetic acid, propionic acid, or lactic acid) from aqueous solutions using methyl isobutyl ketone (MIBK) as extraction agent. Liquid-liquid equilibria data were measured for the mixtures of water + acetic acid + MIBK + TAPS, water + propionic acid + MIBK + TAPS, and water + lactic acid + MIBK + TAPS at T = 298.15 K and 308.15 K under P = 0.1 MPa. MIBK with 5 wt% TAPS biological buffer was found to substantially increase the distribution coefficient (D) and the separation factor (S) for the extraction of carboxylic acids (acetic acid, propionic acid or lactic acid). The LLE data reveal that the order of extraction performance follows propionic acid > acetic acid > lactic acid. The NRTL model accurately represents the LLE behavior for these quaternary systems, with the root mean square deviations (RMSDs) 0.3 %. The COSMO-SAC model was also applied to correlate the LLE data, the deviations between predicted and experimental values were in the range of 7.41 %−16.98 %.

Thymol-menthol-based deep eutectic solvent as a modifier in reactive liquid–liquid extraction of carboxylic acids from pretreated sweet sorghum silage press juice

Reactive liquid–liquid extraction has been widely investigated as a means of isolating carboxylic acids from fermentation broths. However, commonly applied fossil-based solvent phases should be replaced by green alternatives. In this work, we investigate a thymol-menthol-based deep eutectic solvent (tmDES) as a green alternative to the commonly applied modifier 1–octanol for the extraction of lactic acid, acetic acid, and oxalic acid from a model solution and pre-treated sweet sorghum silage press juice (pSPJ); tri–n–octylamine (TOA) was used as a reactive extractant. Additionally, NMR spectroscopy was used to detect interactions between menthol and thymol molecules, as well as among these and TOA and lactic acid. NMR measurements of tmDES revealed the existence of multiple intermolecular contacts between thymol and menthol. Furthermore, nuclear Overhauser effects (NOEs) between the tmDES, TOA, and lactic acid molecules were found. Extraction experiments showed that tmDES improves the extraction efficiency when using pSPJ as the feed phase. The maximum extraction efficiency for lactic acid increased from 35.0 ± 0.8 % to 48.7 ± 0.7 % and for acetic acid from 52.4 ± 0.2 % to 82.2 ± 0.6 % when using a tmDES instead of 1–octanol at 50 °C. Furthermore, the use of tmDES resulted in higher extraction efficiencies as compared to the use of 1–octanol at equilibrium pH values ranging from five to seven, which is a common pH range for fermentation. Besides having superior biocompatibility and extraction efficiency as compared to 1–octanol, tmDES allow carboxylic acid extraction processes to be carried out at higher pH levels.

Interphase distribution of a number of polybasic carboxylic acids in aqueous two-phase systems based on polyethylene glycol-1500

In this work, we studied the interphase distribution of a number of polybasic carboxylic acids, in particular, malic, succinic, glutaric, citric, ascorbic and tartaric in two-phase aqueous systems polyethylene glycol-1500 (PEG-1500) - sodium sulfate - water and PEG-1500 - ammonium sulfate - water. Using the spectrophotometric method of analysis, quantitative characteristics (interfacial distribution and degree of recovery) of the extraction of carboxylic acids were determined. In conclusion, it was found that the considered two-phase aqueous systems are promising in the process of extraction of polybasic carboxylic acids. In particular, the system polyethylene glycol 1500 - sodium sulfate - water has effective extraction properties for succinic malic and ascorbic acids. On the other hand, depending on the composition of the extraction systems, the quantitative characteristics for citric, glutaric and tartaric acids practically do not differ.

Mass transfer analysis and kinetic modeling for process design of countercurrent membrane supported reactive extraction of carboxylic acids

Countercurrent membrane supported reactive extraction (MSRE) was studied for removal of carboxylic acids from aqueous streams with a PTFE capillary membrane. Analysis of the mass transfer rates was performed to support modeling of the process. Total mass transfer coefficients ranging from 2.0·10-7 to 4.0·10-7 m/s were obtained when extracting lactic acid with 20 wt% tri-N-octyl amine in 1-decanol with membrane thicknesses of 260 µm and 80 µm. The limiting mass transfer resistance in all experiments was in the membrane phase. The developed model based on mass transfer and reaction in parallel allows to predict countercurrent extraction. Experimental validation with 5, 7 and 12 m long membrane modules showed excellent accordance for two acids, validating the model simulations. Simulated membrane contactor lengths required for single, two and three countercurrent stages varied between 10 and 39 m/stage for lactic, mandelic, succinic, itaconic and citric acid, depending on acid, membrane, and diluent.

Development of New Hydrophobic Deep Eutectic Solvents Based on Trioctylphosphine Oxide for Reactive Extraction of Carboxylic Acids

Separation of carboxylic acids from their aqueous solutions by reactive extraction using a newly developed deep eutectic solvent (DES) was investigated. DESs were prepared using trioctylphosphine o...

Removal and Extraction of Carboxylic Acids and Non-ionic Compounds with Simple Hydroxides and Layered Double Hydroxides.

Carboxylic acids are an important natural component as a final product or intermediates for syntheses. They are produced in plants, animals and also as products from biotechnological processes. This review presents the use of single hydroxide particles and layered double hydroxides as alternative adsorbents to remove carboxylic acids from liquid media. The proposal to use hydroxide particles is based on its affinity to adsorb or intercalate carboxylic acids. Besides, the change in properties of the adsorbate-sorbate product evinces that this intermediate can be used as a vehicle to transport and release carboxylic acids. Additional examples will also be presented to prove that layered hydroxides are capable of removing non-ionic compounds from wine, milk and tomato. The use of layered compounds to remove active ingredients could reduce the number of separations steps, costs and reduce or eliminate solvents, thus encouraging the design of industrial processes of separation using hydroxides particles.

The effect of fermentation broth composition on removal of carboxylic acids by reactive extraction with Cyanex 923

This paper presents results of liquid-liquid extraction of carboxylic acids, particularly succinic acid (Suc), from one-, two-and multi-component model solutions, and from a fermentation broth with 0.1 and 0.4 mol/L Cyanex 923 (solvating extractant, mixture of trialkylphosphine oxides). As the idea of the extraction is to concentrate Suc in the organic phase, thus, the optimum conditions of extraction are proposed, i.e. 0.4 mol/L Cyanex 923) at low volume of the organic phase (o/w = 1/2), to obtain high extraction efficiency (64%) and to enrich Suc in the organic phase (almost 8 g/L in relation to 6 g/L in the feed). The presence of polyols (propane-1,3-diol, glycerol) in Suc model solutions does not affect Suc extraction efficiency, while the presence of such carboxylic acids as lactic (Lac), acetic (Ac) or formic (For) results in a competition between Suc and other acids. Extraction efficiency of the acids from the real fermentation broth decreases in the following order: But ≫ For ≈ Ac > Lac, which is consistent with their increasing hydrophilicity. The total yield of the proposed extraction-stripping process amounts to 70% recovery of succinic acid. The results prove that the extraction with Cyanex 923 is effective for separation of carboxylic acids from polyols (propane-1,3-diol, glycerol).

Extraction of Carboxylic Acids from Aqueous Solutions by Using [BMim][NTf2] and Salting-out Agents

Levulinic and lactic acids are important feedstock in a wide range of different industries such as polymer, pharmaceutical, or food manufacture. In this work, a study about levulinic acid and lactic acid recovery from their aqueous solutions was carried out using the hydrophobic ionic liquid (IL) 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonil)imide, [BMim][NTf2]. Liquid–liquid equilibria data for the ternary systems water + levulinic acid or lactic acid + IL were determined. The obtained experimental data were correlated by using the nonrandom two-liquid (NRTL) equation. An analysis of the influence of the acid structure and the addition of salting-out agents (potassium phosphate, ammonium sulfate, and saccharose) on the phase equilibria, was also carried out. [BMim][NTf2] was found to be a good extractant for the recovery of levulinic acid and the extraction process was improved by the addition ammonium sulfate.

Influence of Anion and Cation Structure of Ionic Liquids on Carboxylic Acids Extraction.

A recently proposed new mechanism and a model of reactive extraction of carboxylic acids by hydrophobic ionic liquids (ILs) was tested on five systems from published as well as from new equilibrium data on liquid-liquid extraction of butyric and lactic acids (BA and LA) from aqueous solutions. Two phosphonium and one ammonium ILs were used. The model describes experimental data for all systems with a good fit. The mechanism of acid extraction by ILs is very similar for all tested systems. This indicates a more general validity of the developed model. The model allows deeper understanding of regularities in carboxylic acid extraction by hydrophobic ILs. Stability constants of the first acid-IL bonds are by one to three orders of magnitude higher compared to that of acid-acid bonds. Values of stability constants related to two acid-IL bonds are sensitive to a cation and anion structure while stability constants for acid-acid bonds more distant from polar head of IL are not sensitive to IL structure. The stability constants of acid-IL bonds for LA and phosphonium ILs are by more than one order of magnitude lower compared to those for BA and are not influenced with an anion structure. The value of stability constant for the first BA-IL bond is for phosphonium IL with a decanoate anion only one third of those for IL with a phosphinate anion. Differences in the stability of acid-IL bonds for BA and LA can be attributed to hydrophobic interactions which almost do not occur in LA extraction. Ammonium IL also forms a less stable BA-IL bond than the phosphonium IL with the same phosphinate anion. A less stable BA-IL bond can favor the higher recovery of volatile acid from the solvent by vacuum evaporation where free acid is separated instead of acid salts as in classical processes what is a great advantage.

Extraction of propionic acid by emulsion liquid membrane using trioctylamine in toluene

The extraction of carboxylic acids by emulsion liquid membranes has also attracted attention in biotechnology, due to the high selectivity for the desired product, high separation rate and lower costly. The emulsion type liquid membrane system consists of three phases (water/organic/water) in which the organic phase acts as a membrane between the aqueous internal phase and the aqueous external phase. The main parameters such as surfactant concentration, mixing speed, feed phase pH, carrier concentration, and feed phase concentration were investigated. In the optimum conditions, extraction efficiency was obtained 71% in 10 minutes using trioctylamine (5% w/w) as a carrier, Span 80 (4% w/w) as a surfactant, toluene (91% w/w) as a diluent, sodium carbonate (10% w/w) as a stripping solution, mixing speed 300 rpm and feed phase pH 2,5.

Selective oxidation of lignite to carboxyl chemicals

Selective oxidation of lignite to carboxyl chemicals is an important way for the utilization of lignite in a clean and efficient manner. At present, the methods of lignite oxidation to carboxyl chemicals include nitric acid oxidation, sodium hypochlorite oxidation, hydrogen peroxide oxidation, ruthenium-ion-catalyzed oxidation, alkali-oxygen oxidation, catalytic oxygen oxidation and other oxidation. Different methods of lignite oxidation may result in different carboxyl chemicals in compositions and yields. However, the oxidation product is a mixture including several carboxyl chemicals and needs to be separated and purified for further utilization. Therefore, researchers have also studied the separation of carboxylic acids using different ways. In this review, first, different methods of lignite oxidation and their mechanism of lignite oxidation are introduced, and the properties and the problems of the oxidation methods are analyzed. Second, the extraction of carboxylic acids in reaction solutions and the separation of carboxylic acid mixtures and the existing problems are also reviewed and discussed. Although many efforts have been paid to the selective oxidation of lignite to carboxyl chemicals, many problems still exist in the ways to industrial applications. Therefore, finally, the challenges and possible future developments in selective oxidation of lignite to carboxyl chemicals are analyzed and outlined.

Separation of Protocatechuic Acid Using Di-(2-ethylhexyl)phosphoric Acid in Isobutyl Acetate, Toluene, and Petroleum Ether

Protocatechuic acid has potential pharmacological significance, like antioxidant, antibacterial, and anticancer activity. The extraction of carboxylic acids from dilute aqueous phase is a topic of current interest to researchers. The present equilibrium study deals with the reactive extraction of protocatechuic acid from an aqueous solution by using di-(2-ethylhexyl)phosphoric acid (D2EHPA) in diluents, such as isobutyl acetate (IBA), toluene, and petroleum ether at isothermal conditions (298 ± 1 K). The physical extraction of protocatechuic acid with pure diluents is also carried out. The difference between the physical extraction and the reactive extraction was studied. The effects of acid concentration (0.001–0.01 mol·kg–1), extractant concentration (0.3445–3.1010 mol·kg–1), and type of diluent on the recovery of protocatechuic acid from aqueous solution were determined. KD values were obtained in the ranges of 1.14–4.03, 0.12–0.67, and 0.08–0.48 for D2EHPA in isobutyl acetate, toluene, and petroleum e...

Reactive extraction of carboxylic acids using organic solvents and supercritical fluids: A review

Abstract A review of the current applications of organic compounds and supercritical fluids as solvents for separation of carboxylic acids from aqueous solutions by physical and reactive extraction is presented. A comparison of efficiencies of acetic, propionic, succinic, and citric acid extraction by using 1-octanol and supercritical CO2 performed in the batch mode and the semi-continuous mode is presented. Supercritical CO2 is a recommended solvent for use in the reactive extraction of carboxylic acids because of its environmentally benign, non-toxic, non-flammable, non-polluting and recoverable characteristics. It is concluded that the supercritical reactive extraction process is an efficient method of carboxylic acid separation from aqueous solutions with higher yield, simplicity, and competitiveness than the other separation methods.

Theoretical and Experimental Studies on Extraction of Carboxylic Acids from Aqueous Solution Using Ionic Liquids

Theoretical and Experimental Studies on Extraction of Carboxylic Acids from Aqueous Solution Using Ionic Liquids

Specific phenomena in carboxylic acids extraction by selected types of hydrophobic ionic liquids

An overview on specific phenomena in extraction of carboxylic acids with hydrophobic ionic liquids (ILs) based on results of new measurements with selected phosphonium, ammonium and imidazolium ILs and published data is presented. Formation of IL – acid hydrated complexes with multiple molecules of organic acid per one IL ion pair was observed. The distribution coefficient of carboxylic acids and water content in ILs strongly decreases with the increasing acid concentration. Dependence of water content in the solvent passes through a minimum at loading of IL with butyric acid of about 3. Two extraction mechanisms are involved: competitive extraction of acid and water with the release of water from the solvent and co-extraction of water with acid depending on the IL concentration. A strong synergistic effect was observed between the cation and anion of ILs enhancing their extractive properties compared to IL precursors. A new extraction model suggests the formation of water bridges and polar nano-channels which is in agreement with the molecular modelling results. ILs are nano-segregated liquids with a structure sensitive to the content of molecular compounds. Water and carboxylic acids accumulate in polar domains and dodecane in non-polar domains modifying the IL structure and decreasing the solvent phase viscosity. The hypothesis of hopping mechanism in polar channels for acid molecules transport between acid chains at IL binding sites is suggested.

Extraction of carboxylic acids with neutral extractants

In the review, the features of the interphase distribution of weak acids (K а < 10–2) in the systems containing neutral extractants have been considered. Experimental results of studies of the extraction of monocarboxylic acids have been described. The possibilities of using extraction processes for the isolation and separation of monocarboxylic acids from solutions of various compositions have been shown.

Reactive Separation of Benzeneacetic Acid with Tri-n-caprylyl Amine: Equilibrium and Modeling

Benzeneacetic acid is an important carboxylic acid extensively used in pharmaceutical industries. Thus, interest has been growing in the scientific community toward its recovery from aqueous streams or fermentation broth. Extraction of carboxylic acids by reactive extraction using extractant-diluent is the emerging area of study. With this concept, the reactive extraction of benzeneacetic acid was carried out to study (i) effect of diluents, such as benzene, toluene, xylene, and hexanol; (ii) effect of concentration of extractant, tri-n-caprylyl amine; (iii) effect of pH; and (iv) equilibrium modeling, namely, relative basicity model and mass action law. The equilibrium results are discussed in terms of partition coefficient (P), dimerization constant (D), distribution coefficient (KD), extraction efficiency (η%), overall equilibrium complexation constant (Ke), and loading factor (ϕ). Distribution coefficient trend was observed as xylene > benzene > toluene > hexanol. The extraction efficiency of benzenea...