New reactive extraction systems for separation of bio-succinic acid

Biotechnologically produced succinic acid has the potential to displace maleic acid and its uses and to become an important feedstock for the chemical industry. In addition to optimized production strains and fermentation processes, an efficient separation of succinic acid from the aqueous fermentation broth is indispensable to compete with the current petrochemical production processes. In this context, high molecular weight amines are known to be effective extractants for organic acids. For this reason, as a first step of isolation and purification, the reactive extraction of succinic acid was studied by mixing aqueous succinic acid solutions with 448 different amine–solvent mixtures as extraction agents (mixer-settler studies). The extraction agents consist either of one amine and one solvent (208 reactive extraction systems) or two amines and two solvents (240 reactive extraction systems). Maximum extraction yields of succinic acid from an aqueous solution with 423 mM succinic acid at pH 2.0 were obtained with more than 95% yield with trihexylamine solved in 1-octanol or with dihexylamine and diisooctylamine solved in 1-octanol and 1-hexanol. Applying these optimized reactive extraction systems with Escherichia coli fermentation broth resulted in extraction yields of 78–85% due to the increased ionic strength of the fermentation supernatant and the co-extraction of other organic acids (e.g., lactic acid and acetic acid), which represent typical fermentation byproducts.     

Effects of organic phase, fermentation media, and operating conditions on lactic Acid extraction

Lactic acid has extensive uses in the food, pharmaceutical, cosmetic and chemical industry. Lately, its use in producing biodegradable polymeric materials (polylactate) makes the production of lactic acid from fermentation broths very important. The major part of the production cost accounts for the cost of separation from very dilute reaction media where productivity is low as a result of the inhibitory nature of lactic acid. The current method of extraction/separation is both expensive and unsustainable. Therefore, there is great scope for development of alternative technology that will offer efficiency, economic, and environmental benefits. One of the promising technologies for recovery of lactic acid from fermentation broth is reactive liquid-liquid extraction. In this paper the extraction and recovery of lactic acid based on reactive processes is examined and the performance of a hydrophobic microporous hollow-fiber membrane module (HFMM) is evaluated. First, equilibrium experiments were conducted using organic solutions consisting of Aliquat 336/trioctylamine (as a carrier) and tri-butyl phosphate (TBP)/sunflower oil (as a solvent) The values of the distribution coefficient were obtained as a function of feed pH, composition of the organic phase (ratio of carrier to solvent), and temperature (range 8-40 degrees C). The optimum extraction was obtained with the organic phase consisting of a mixture of 15 wt % tri-octylamine (TOA) and 15% Aliquat 336 and 70% solvent. The organic phase with TBP performed best but is less suitable because of its damaging properties (toxicity and environmental impact) and cost. Sunflower oil, which performed moderately, can be regarded as a better option as it has many desirable characteristics (nontoxic, environment- and operator-friendly) and it costs much less. The percentage extraction was approximately 33% at pH 6 and at room temperature (can be enhanced by operating at higher temperatures) at a feed flow rate of 15-20 L/h. These results suggest that the hollow-fiber membrane process yields good percentage extraction at the fermentation conditions and its in situ application could improve the process productivity by suppressing the inhibitory effect of lactic acid.     

Integrated separation process for isolation and purification of biosuccinic acid

Biotechnologically produced succinic acid has the potential to displace maleic acid and its uses. Therefore, it is of high interest for the chemical, pharmaceutical, and food industry.In addition to optimized production strains and fermentation processes, an efficient separation of succinic acid from the aqueous fermentation broth is indispensable to compete with the current petrochemical production of succinic acid. Isolation and purification of succinic acid from an Escherichia coli fermentation broth were studied with two amine-based reactive extraction systems: (i) trihexylamine in 1-octanol and (ii) diisooctylamine and dihexylamine in a mixture of 1-octanol and 1-hexanol. Back extraction of succinic acid from the organic phase was carried out using an aqueous trimethylamine solution. The trimethylammonium succinate generated after back extraction was split with an evaporation-based crystallization.The focus was on process integration, for example, reuse of the applied amines for extraction and back extraction. It was shown that the maximum trimethylamine concentration for back extraction should not exceed the stoichiometric amount (2 mol trimethylamine/mol the succinic acid in the organic phase) to ensure maximal extraction yields with the reused organic phase in subsequent extractions. Moreover, mixer-settler extraction and back extraction of succinic acid were scaled up from the milliliter- to the liter-scale making use of liquid–liquid centrifuges. The overall yield was 83.5% of the succinic acid from thefermentation supernatant. The final purity of the succinic acid crystals was 99.5%. Organic phase and amines can easily be recycled and reused.     

Extraction of succinic acid with 1-octanol/n-heptane solutions of mixed tertiary amine

The reactive extraction of succinic acid was carried out by mixed tertiary amine which consisted of tripropylamine (TPA) and trioctylamine (TOA) as the extraction agent in 1-octanol/n-heptane diluent. Maximum distribution coefficient was obtained at 8:2 weight ratio of TPA/TOA. At this ratio, its extraction efficiency is above 90% at the 3.9 wt.% of succinic acid in aqueous solution. Furthermore, the prevention of the third phase formation made the phase separation between organic phase and aqueous phase easy.     

Reactive extraction of lactic acid using alamine 336 in MIBK: equilibria and kinetics

Lactic acid is an important commercial product and extracting it out of aqueous solution is a growing requirement in fermentation based industries and recovery from waste streams. The design of an amine extraction process requires (i) equilibrium and (ii) kinetic data for the acid-amine (solvent) system used. Equilibria for lactic acid extraction by alamine 336 in methyl-iso-butyl-ketone (MIBK) as a diluent have been determined. The extent to which the organic phase (amine +MIBK) may be loaded with lactic acid is expressed as a loading ratio, z=[HL](o)/[B](i,o). Calculations based on the stoichiometry of the reactive extraction and the equilibria involved indicated that more lactic acid is transferred to the organic phase than would be expected from the (1:1) stoichiometry of the reaction. The extraction equilibrium was interpreted as a result of consecutive formation of two acid-amine species with stoichiometries of 1:1 and 2:1. Equilibrium complexation constant for (1:1) and (2:1) has been estimated. Kinetics of extraction of lactic acid by alamine 336 in MIBK has also been determined. In a first study of its kind, the theory of extraction accompanied by a chemical reaction has been used to obtain the kinetics of extraction of lactic acid by alamine 336 in MIBK. The reaction between lactic acid and alamine 336 in MIBK in a stirred cell falls in Regime 3, extraction accompanied by a fast chemical reaction occurring in the diffusion film. The reaction has been found to be zero order in alamine 336 and first order in lactic acid with a rate constant of 1.38 s(-1). These data will be useful in the design of extraction processes.     

Selective separation of amino acids by reactive extraction

The method of reactive extraction with di-(2-ethylhexyl)phosphoric acid (D2EHPA) for the separation of a range of amino acids is studied. The results obtained on the individual reactive extraction indicated the possibility of the amino acids selective separation as a function of the pH value of aqueous solution and the acidic or basic character of each amino acid. Thus, using multistage extraction, the total separation of the following amino acids groups has been performed: neutral amino acids (l-glycine, l-alanine, l-tryptophan) at pH 5–5.5 (nine extraction stages), basic amino acids (l-lysine, l-arginine) and l-cysteine at pH 4–4.5 (ten extraction stages), l-histidine at pH 3–3.5 (five extraction stages), and acidic amino acids (l-aspartic acid, l-glutamic acid) at pH 2–2.5 (three extraction stages).     

Process optimization of chiral extraction of 2,3-diphenylpropionic acid by experiment and simulation

This paper reports the process optimization of chiral extraction of 2,3-diphenylpropionic acid (2,3-2-PPA) enantiomers by experiment and simulation in centrifugal contactor separators. An efficient extraction system was obtained firstly through single-stage extraction experiments and single-stage extraction model, where sulfobutylether-β-cyclodextrin (SBE-β-CD) and 1,2-dichlorethane were selected as the optimal extractant and organic solvent, respectively. The mechanism of the extraction system was proposed and the thermodynamic constants such as physical partition coefficient and reactive equilibrium constants were obtained. Based on phase and reactive equilibrium as well as the law of mass conservation, a model describing the fractional extraction process was acquired. The process of symmetrical separation of 2,3-2-PPA enantiomers was optimized by the fractional extraction model. The optimal conditions composed of flow rate ratio (W/O) of 3.0, pH of 3.00 and SBE-β-CD concentration of 0.10 mol/L were obtained. Under this case, equal enantiomeric excess (ee_eq) can reach up to 37% at 10 stages. The simulated results reveal that the minimum series for ee_eq > 97% and ee_eq > 99% was 78 and 102, respectively.     

Application of reactive extraction to recovery of carboxylic acids

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.     

Solid phase extraction procedure for urinary organic acid analysis by gas chromatography mass spectrometry

We have developed a solid phase extraction procedure for the detection of organic acids by GC-MS using a strong anion exchange column (Sep-Pak Vac RC, Accell Plus QMA cartridge). Extraction efficiencies of 25 organic acids were established by analyzing standards in water based solutions. High extraction efficiencies (90 to 100%) were found for many of the compounds studied. We estimated the limit of detection for 48 organic acids and glycine conjugates. They were below 5 nmole with the exception of malonic and oxalic acids and mevalonic acid lactone. This method provides the advantage of higher recoveries for a wide range of compounds of interest and therefore can be a potential alternative to liquid-liquid extraction for organic acid screening. It is especially sensitive for the detection of some polar compounds, such as 3-OH-glutaric and N-acetylaspartic acids.     

Reaction equilibrium of penicillin G with amberlite LA-2 in a nonpolar organic solvent

Studies have been made of the reactive extraction of penicillin G by Amberlite LA-2, a secondary amine, dissolved in kerosene. On the basis of the previous works about extraction equilibria of monocarboxylic acids by some secondary amines in low polar organic solvents, four equilibrium models were suggested to describe the reaction equilibrium of penicillin G in the liquid-liquid extraction system. The calculated results from the models were compared with the experimental data of 96 runs, and only two equilibrium models seemed to be probable. Ultimately, the most reasonable extraction equilibrium model was chosen through spectroscopic studies on organic solutions obtained by five specific extraction equilibrium experiments.     

Determination of valproic acid in human serum and pharmaceutical preparations by headspace liquid-phase microextraction gas chromatography-flame ionization detection without prior derivatization

An efficient and fast extraction technique for the enrichment of valproic acid from human blood serum samples using the headspace liquid phase microextraction (HS-LPME) combined with gas chromatography (GC) analysis has been developed. The extraction was conducted by suspending a 2 microL drop of organic solvent in a 1 mL serum sample; following 20 min of extraction, withdrawing organic solvent into a syringe and injection into a GC with a flame ionization detector (FID), without any further pre-treatment. Four organic solvents, 1-decanole, benzyl alcohol, 1-octanol and n-dodecane, were studied as extractants, and n-dodecane was found to be the most sensitive solvent for valproic acid. The results revealed that HS-LPME is suitable for the successful extraction of valproic acid from human blood serum samples. Parameters like extraction time, ionic strength, pH, organic solvent volume, and temperature of the sample were studied and optimized to obtain the best extraction results. An enrichment factor of 27-fold was achieved in 20 min. The procedure resulted in a relative standard deviation of <13.2% (n=7) and a linear calibration range from 2 to 20 microg mL(-1) (r>0.98), and the limit of detection was 0.8 microg mL(-1) in serum blank samples. Overall, LPME proved to be a fast, sensitive and simple tool for the preconcentration of valproic acid from real samples. The proposed method was also applied to the analysis of valproate in pharmaceutical preparations.     

Separation of lactic acid from fermented broth by reactive extraction

The separation of lactic acid from complex fermentation broth was examined. Liquid–liquid extraction using reversible chemical complexation for reactive extraction was chosen to be the separation method. Over 50% yield of lactic acid was obtained from fermented broth in a single extraction step, when using the tertiary amine as the extractant, 1-dekanol as the diluent and trimethylamine (TMA) as the stripping solution. The effect of complex media on the extraction behaviour has hardly been examined previously.     

Extraction of steroidal glucosiduronic acids from aqueous solutions by anionic liquid ion-exchangers

A pilot study on the extraction of three steroidal glucosiduronic acids from water into organic solutions of liquid ion-exchangers is reported. A single extraction of a 0.5mm aqueous solution of either 11-deoxycorticosterone 21-glucosiduronic acid or cortisone 21-glucosiduronic acid with 0.1m-tetraheptylammonium chloride in chloroform took more than 99% of the conjugate into the organic phase; under the same conditions, the very polar conjugate, beta-cortol 3-glucosiduronic acid, was extracted to the extent of 43%. The presence of a small amount of chloride, acetate, or sulphate ion in the aqueous phase inhibited extraction, but making the aqueous phase 4.0m with ammonium sulphate promoted extraction strongly. An increase in the concentration of ion-exchanger in the organic phase also promoted extraction. The amount of cortisone 21-glucosiduronic acid extracted by tetraheptylammonium chloride over the pH range of 3.9 to 10.7 was essentially constant. Chloroform solutions of a tertiary, a secondary, or a primary amine hydrochloride also will extract cortisone 21-glucosiduronic acid from water. The various liquid ion exchangers will extract steroidal glucosiduronic acid methyl esters from water into chloroform, although less completely than the corresponding free acids. The extraction of the glucosiduronic acids from water by tetraheptylammonium chloride occurs by an ion-exchange process; extraction of the esters does not involve ion exchange.     

Construction and application of a model on the resolution of tropic acid enantiomers by enantioselective liquid-liquid extraction in centrifugal contactor separators

This paper reports on the construction and application of a mathematical model on multistage liquid-liquid extraction of tropic acid (TA) enantiomers in centrifugal contactor separators (CCSs). An efficient extraction system was obtained, where HE-β-CD and butyl acetate was selected as the best extractant and organic solvent. The mechanism of reactive extraction of TA enantiomers by HE-β-CD was proposed and the thermodynamic constants such as physical partition coefficient and reactive equilibrium constants were obtained, which combined with the law of mass conservation gave the basis for construction of the model. The model was applied to predict and optimize the symmetrical separation of TA enantiomers. The optimal condition was obtained as follows, O/W volume ratio of 3.0, pH of 3.00 and HE-β-CD concentration of 0.05 mol/L, where ee_eq (equal enantiomeric excess) can reach up to 42%. The simulated results reveal that the minimum number of stages for ee_eq > 97% and ee_eq > 99% was 56 and 78, respectively.     

Investigations of biocompatible systems for reactive extraction of propionic acid using aminic extractants (TOA and Aliquat 336)

This paper presents the reactive extraction of propionic acid from aqueous solution by amine based extractants such as tri-n-octylamine and Aliquat 336, dissolved in a mixture of n-dodecane and 1-decanol. Equilibrium experiments were carried out to investigate the effects of various parameters such as modifier (1-decanol) concentration, extractant type, extractant composition, diluent composition, and initial acid concentration on the extraction efficiency. The extraction efficiency was found to be increased with an increase in modifier composition and extractant composition, and decreased with increases in initial acid concentration. Different biocompatible extractant/diluent systems such as (1) 20% TOA, 20% 1-decanol and 60% n-dodecane, (2) 20% TOA, 30% 1-decanol and 50% n-dodecane, (3) 30% TOA, 20% 1-decanol and 50% n-dodecane and (4) 25% Aliquat 336, 25% 1-decanol and 50% n-dodecane are developed and used in this study. A mathematical model based on mass action law and a population-based search algorithm (differential evolution, DE) is proposed, and is used to estimate the extraction equilibrium constant (K _E) and stoichiometry of reactive extraction. Individual equilibrium constants for the simultaneous formation of (1:1) and (2:1) acid:amine complexes are also determined. The extraction system comprised of 20% TOA, 30% 1-decanol, and 50% n-dodecane was found to be the best among the four biocompatible extractant/diluent systems studied. The loading ratios found in the range of 0.113 ～ 1.05 indicated the simultaneous formation of 1:1 and 2:1 complexes between acid and TOA.     

Reactive extraction of succinic acid with tripropylamine (TPA) in various diluents

Succinic acid is of interest as the raw material of polysuccinate which is a biodegradable polymer. The tripropylamine (TPA) was used as the extraction agent for the reactive extraction of succinic acid in various alcohol diluents. Equilibrium and loading data for various active diluents were obtained at various TPA concentrations. At the same TPA concentration the extractabilities of TPA increased as the number of carbon in alcohols decreased. It was explained by decreasing solubility of acid-amine complex due to decreasing polarity with increasing the number of carbon in alcohols. The type of succinic acid-amine-diluent complex was predicted by the value of loading with various concentration of TPA/various alcohols.     

Measurement of inorganic orthophosphate in biological materials: Extraction properties of butyl acetate

The properties of several organic solvents were investigated to determine their suitability for use in phosphomolybdic acid (PMA) extraction procedures for the measurement of inorganic orthophosphate (P_i). Butyl acetate exhibited the most satisfactory properties for measurements at 310 nm, which is the absorption peak for unreduced PMA. Butyl acetate exhibits essentially no absorption at 310 nm, is highly selective for PMA over molybdate and silicomolybdate, does not extract molybdate in the presence of trichloroacetic acid (TCA), exhibits negligible volume changes when equilibrated with equal volumes of aqueous phase, and is among the least toxic of organic solvents. Optimal conditions of acidity, molybdate concentration, and reaction and extraction times were determined for the formation of PMA and extraction into butyl acetate. A procedure for measurement of P_i in biological material employing 8% TCA for precipitation of organic material at 0°C, reaction of the supernatant with acid molybdate, extraction of the PMA with butyl acetate and reading of unreduced PMA at 310 nm is described. The procedure is simple, rapid, accurate, selective, and has high sensitivity. Because of the short (20 sec) sample exposure to acid molybdate, it is suggested that the procedure may also be useful in the measurement of P_i in the presence of adenosine triphosphate such as for the assay of adenosinetriphosphatase activity.     

Reactive extraction and reextraction of penicillin with different carriers

The extraction and reextraction of Penicillin G was investigated with different reactive components. The degrees E_R of reextraction and E_G extraction + reextraction were evaluated as a function of the pH value, carrier and penicillin concentrations. Besides Amberlite LA-2, nine different reactive components were tested and diisotridecylamine was found to be the most suitable one. The quaternary ammonium salt Adogen 464 is suitable also for the extraction of penicillin. However, the reextraction is incomplete. Therefore, sodium salt of p-toluene sulfonic acid was used as counter-ion, and it was regenerated by NaOH or Cl⁻ anion. The advantages of the use of quaternary ammonium salts are discussed.     

紫色小白菜有机酸的提取优化及UPLC定量分析

为建立一种紫色小白菜中精准的有机酸提取及定性定量分析方法。本研究在单因素试验的基础上,采用Box-Behnken的中心组合试验设计原理,设计响应面试验优化紫色小白菜有机酸的提取工艺。结果表明,紫色小白菜有机酸提取的最优工艺参数为:乙醇浓度73%,料液比1∶21,超声时间11 min,超声温度70℃。通过超高效液相色谱法(ultra performance liquid chromatography,UPLC)对紫色小白菜叶片和叶柄部位有机酸进行定性定量分析,检测出苹果酸、柠檬酸、丙二酸、琥珀酸和酒石酸,其中苹果酸含量最高,分别为15.968、5.019 mg/g;其次为柠檬酸,分别为9.293、1.385 mg/g。定性定量结果表明,紫色小白菜叶片及叶柄部位含有丰富有机酸类物质,叶片部位苹果酸、柠檬酸、丙二酸、酒石酸含量均高于叶柄部位,而琥珀酸含量较低。     

In situ lipase-catalyzed reactive extraction of oilseeds with short-chained dialkyl carbonates for biodiesel production

Dimethyl/diethyl carbonate was adopted as extraction solvent and transesterification reagent at the same time for in situ lipase-catalyzed reactive extraction of oilseeds for biodiesel production in this work. Fatty acid methyl esters and ethyl esters were respectively obtained with higher yields than those achieved by conventional two-step extraction/transesterification. The augment ranged from 15.7% to 31.7%. The key parameters such as solvent/seed ratio and water content were further investigated to find their effects on the in situ reactive extraction. The highest yields of Pistacia chinensis Bunge methyl ester, P. chinensis Bunge ethyl ester, Jatropha curcas L methyl ester and J. curcas L ethyl ester could attain 89.6%, 90.7%, 95.9% and 94.5%, respectively under the optimized conditions.