Amberlite LA-2 Research Articles

REACTIVE EXTRACTION OF BETA-LACTAM ANTIBIOTICS: IR SPECTROSCOPIC STUDIES

Infrared spectroscope study on reactive extraction of Cephalosporin-C (CPC) and 6-Aminopenicillanic acid (6-APA) with secondary and tertiary amines and a quaternary amine salt as the extractants in butyl acetate as the diluent has been reported. The study aims at analysing the chemical interaction involved in the complexation of the molecules with the extract-ant and the reaction stoichiometry. Amberlite LA-2, Trioctylamine and Aliquat-336 (Tricaprylyl methyl ammonium chloride) were used as the extractants. The results of experimental extraction equilibrium study and spectroscopic analysis indicate the formation of (1:1) complex vie ion-exchange reaction of CPC and 6-APA with Aliquat-336. The ion-pair extraction with Amberlite LA-2 and Trioctylamine exhibited non-stoichiometric complexation in accordance with experimental observation on equilibrium relationship

Reactive extraction of penicillin G in hollow-fiber and hollow-fiber fabric modules.

Penicillin G (Pen G) can be rapidly extracted in hollow-fiber liquid-liquid contactors using N-lauryl-N-trialkylmethylamine (Amberlite LA-2) as the extractant. n-Butylacetate is much better than decanol as a diluent for such an extraction, although decanol can give a partition coefficient four times larger. The overall mass transfer coefficient found is a function of aqueous flow on the lumen side of the fiber, and is less dependent on shell-side flow. In backextraction, the overall mass transfer coefficient determined is only one tenth that of the forward extraction, primarily because the hydrophobic hollow fibers used have a high mass transfer resistance under these conditions. The mass transfer experiments show that hollow-fiber extraction of Pen G is competitive with centrifugal extraction. The prospects for extraction of other fermentation products with hollow fibers can be estimated based on the present study.

Selective separation of penicillin V from phenoxyacetic acid using liquid membranes

The selective separation of Penicillin V from phenoxyacetic acid using extraction and transport through liquid membranes consisting of 1,2-dichloroethane and Amberlite LA-2 as carrier was studied. The selective separation is the result of the difference between the acidity and hydrophobicity of the two compounds. The experimental data indicated the decisive influences of pH (difference between the feed and stripping phases), carrier concentration in solvent phase (0–80 g/l Amberlite LA-2) and mixing intensity. Thus, the selectivity factor, defined as the ratio between the final mass flows of Penicillin V and phenoxyacetic acid, was enhancing by reducing the pH gradient between the aqueous solutions and by using low concentrations of carrier inside the liquid membrane, in the conditions of high stirrers rotation speed values. The selectivity factor value varied between 2.5 and 80.4.

Solvent extraction of Au(CN) 2− and application to facilitated supported liquid membrane transport

The solvent extraction of gold(I) from aurocyanide solutions by means of various reagents: amines (Primene JMT, Amberlite LA2, Alamine 336), solvation extractants (TBP, Cyanex 921, DMPL) and mixtures of both is reported. Different variables that could affect the systems were evaluated; on the basis of the numerical treatment of experimental data, the stoichiometries of the extracted species (generally represented by HAu(CN) 2·R·L q , R being the amine, L the solvation extractant and q depending either of the amine and/or the solvation reagent) are proposed. The permeation of Au(I) through a supported liquid membrane impregnated with various of the extractants has been investigated. High selectivity in the separation, through supported liquid membrane, of Au(I) against different metal–cyano complexes (Ag(CN) 2 −, Cu(CN) 4 3−, Zn(CN) 4 2−, Fe(CN) 6 3−) is achieved.

Mathematical modeling of penicillin G extraction in an emulsion liquid membrane system containing only a surfactant in the membrane phase

An extraction experiment of penicillin G was performed in an emulsion liquid membrane system in which only ECA 4360J exists in the organic membrane phase without a predominant carrier, Amberlite LA-2, used in our previous works and it functions as a carrier as well as a surfactant. A permeation model for the present system has been developed as a primary study to examine the transport mechanism of penicillin G in the previous batch and continuous systems with two carriers of Amberlite LA-2 and ECA 4360J. The model takes into account the mass transfer in the external aqueous film, the extraction reaction between penicillin G and ECA 4360J at the external interface, the diffusion of penicillin G in the emulsion phase, the stripping reaction at the internal interface and the pH change of internal aqueous solution containing Na 2CO 3 with penicillin G transported into the internal phase. The experimental data were well fitted with the present model. Also, an expression for the reaction of penicillin G with ECA 4360J was obtained through a series of equilibrium measurements in liquid–liquid extraction system.

On the Purification of β-Naphthalenesulfonic Acid from Dilute Aqueous Solutions Containing Sulfuric Acid

In the development of a biological process for the production of β-naphthol starting from β-naphthalenesulfonic acid, the purification of the acid from dilute aqueous solutions containing sulfuric acid is of relevant importance. We investigate the feasibility of carrying out such a purification using the secondary amine Amberlite LA-2 dissolved in toluene. Experimental measurements were performed with aqueous solutions of β-naphthalenesulfonic acid (NSA) in the concentration range 0.01−0.5 m. The organic phase comprised 0.5 m of Amberlite in the diluent toluene. Experimental results were modeled to determine the Nernst distribution coefficients of NSA and sulfuric acid and the infinite dilution selectivity. The obtained value of this last parameter shows that separation is thermodynamically favored.

Carrier-facilitated liquid membrane extraction of penicillin G from aqueous streams

Kinetics and mechanism for the carrier-facilitated transport of penicillin G from aqueous solutions through a supported liquid membrane containing Amberlite LA-2 were investigated. The strip phase was either phosphate buffer or sodium carbonate solution. Experiments were performed as a function of the pH, the concentrations of penicillin G in the feed phase and of amine in the membrane phase. A transport model was proposed considering aqueous film diffusion, interfacial chemical reaction, and membrane diffusion. The calculated rates were found to agree with the measured ones (average standard error, 12%). Under the conditions investigated (feed pH 5.02–7.83, penicillin G concentration 10–500 mol/m 3, amine concentration 50–1000 mol/m 3), the present transport process was shown to be governed by combined interfacial chemical reaction and membrane diffusion.

Investigation on interfacial reaction kinetics of penicillin G and Amberlite LA-2 from membrane flux measurements

Interfacial reaction kinetics for reactive extraction of penicillin G from aqueous solutions by Amberlite LA-2 in a mixture of kerosene and n-butyl acetate were studied using a microporous membrane-based stirred cell. This operation gave intrinsic rate equations for formation and dissociation of the Amberlite LA-2 complex of penicillin G occurring at or near the organic–aqueous interface. The effect of temperature on the reaction rates was also examined and the activation energies were determined. On the basis of the reaction kinetics and transport parameters within two stagnant layers, the fractional resistances of aqueous layer diffusion, interfacial chemical reaction, and organic layer diffusion were quantitatively determined in this liquid–liquid extraction process (forward and backward), and thus the transport mechanism was clarified.

Preliminary report on fractionation of fucans by ion-exchange displacement centrifugal partition chromatography

A new method combining ion-exchange displacement chromatography with centrifugal partition chromatography (CPC) was used for the fractionation of partially depolymerized fucans (polysulphated polysaccharides). The ion-exchanger was Amberlite LA2, a high-molecular-mass liquid secondary amine miscible with most common organic solvents and immiscible with aqueous solutions. Ion-exchange displacement centrifugal partition chromatography was performed with LA2 in methyl isobutyl ketone (MiBK) as the stationary phase, water as the mobile phase, Cl− as the carrier and OH− as the displacer. A complex mixture of partially depolymerized fucans was resolved into adjacent families characterized by their peak molecular mass and polydispersity. The Dubois test (sugar) and the azur A test (SO3−) confirmed the displacement mode of the process, and size-exclusion chromatographic controls confirmed its efficiency.

Pertraction of Penicillin G in Hollow Fiber Contained Liquid Membranes

Pertraction of Penicillin G in Hollow Fiber Contained Liquid Membranes was investigated in a system consisting of 2 Liqui Cel 106 modules from Hoechst Celanese. The flux of Pen G depended upon the content of n-octanol and of Amberlite LA2 in kerosene used as a membrane phase. During the pertraction of Pen G in HFCLM system the pH difference between the both buffered aqueous phases diminished proportionally to the contact time with the membrane phase. The flux of citric acid used as a buffer component in the feed phase attained 11.8 mM/m2·h and was comparable with the flux of Pen G equal to 18.4 mM/m2·h. In order to eliminate the undesired transport of citric acid, CO2 was used as a volatile buffer component. Although the pH values were stabilised in the range of 5.47 and 7.45 in the feed and strip phase, respectively, the achieved Pen G flux was significantly lower.

Extraction of Anions from Aqueous Solutions Using Secondary Amines

Extraction of strong mineral acids (HCl and H2SO4) from aqueous solutions was carried out using the secondary amine Amberlite LA-2. Experimental measurements were performed with aqueous solutions in the concentration range 0.01−0.5 m. The organic phase comprised 0.5 m Amberlite in diluent toluene. Experimental results were modeled to determine the Nernst distribution coefficients of the two acids and the infinite dilution selectivity. The affinity for H2SO4 is found to be greater than that for HCl.

REACTIVE EXTRACTION OF DICARBOXYLIC ACIDS I. MECHANISM, LIMITING STEPS AND KINETICS

In this paper the reactive extraction of some dicarboxylic acids (oxalic acid, malonic acid, succinic acid, glutaric acid, and adipic acid) have been studied. These acids have been extracted by Amberlite LA-2 in butyl acetate using a modified extraction cell of the Lewis type. Mechanism, limiting steps, and kinetic of the mass transfer process have been settled.

Removal of valeric acid from wastewaters by membrane contactors

Membrane contactors, providing a non-dispersive extraction technique, were used for the removal of valeric (n-pentanoic) acid from synthetic aqueous solutions simulating an industrial wastewater from polymer manufacturing. Amberlite LA-2 (secondary amine) in toluene was chosen as the extraction system. Equilibrium conditions were determined and mechanistically modelled for different extractant concentrations allowing the further calculation of mass transfer coefficients. The influence of the hydrodynamics of both the aqueous and organic phases on the overall mass transfer coefficient, calculated through two proposed methods, was studied. The integration of extraction and backextraction was also carried out, allowing a further acid removal with lower extractant concentrations.

Integrated membrane extraction, enzymic conversion and electrodialysis for the synthesis of ampicillin from penicillin G

Penicillin G was continuously extracted from an aqueous buffer solution at pH 5 across a membrane of Amberlite LA-2 isodecanol kerosene solution in a Hoechst-Celanese hollow fibre membrane module, and re-extracted from the organic phase across a membrane by phosphate buffer solution at pH 8 in a second Hoechst-Celanese hollow fibre module. The penicillin G in the stripping phase was converted to phenylacetic acid (PAA) and 6-aminopenicillanic acid (6-APA) by free and immobilized penicillin G amidase (PA) in phosphate buffer solution, respectively. PAA was removed from the reaction mixture by electrodialysis. For this purpose sandwich and composite bipolar membranes were compared, based on the electrodialysis of acetate and citrate. The electrodialysis of penicillin G, PAA, 6-APA and phosphate were investigated under various operational conditions to determine the optimal conditions for the retention of 6-APA and the removal of PAA from the reaction mixture at optimal pH value for the stripping of penicillin G and its conversion to PAA and 6-APA. PAA was removed from the educt cycle by electrodialysis into the product cycle. The pH in the educt cycle was reduced to a value of 6 by permeation of phosphate into the product cycle. Free and immobilized PA, respectively, and phenylglycine ethyl ester (PGE) were added to the educt cycle of the electrodialyser and the latter reacted with 6-APA to form ampicillin.

RECOVERY OF GALLIUM FROM COAL FLY ASH BY A DUAL REACTIVE EXTRACTION PROCESS

The extraction of gallium from coal fly ash by leaching and extraction with commercial extractants Amberlite LA-2 and LIX 54N dissolved in kerosene was studied. Leaching of gallium and other metals from the fly ash was carried out with 6 M hydrochloric acid. The leaching liquor is first contacted with Amberlite LA-2 which extracts the gallium and iron. The iron is then precipitated with sodium hydroxide, while gallium remains in solution. Gallium is extracted selectively from the base solution with LIX 54; the resulting stripped solution contains 83% of the gallium present in the leaching liquor. A flow diagram for this dual-extraction process is proposed.

Recovery of Gallium From Coal Fly Ash By a Dual Reactive Extraction Process

The extraction of gallium from coal fly ash by leaching and extraction with commercial extractants Amberlite LA-2 and LIX 54N dissolved in kerosene was studied. Leaching of gallium and other metals from the fly ash was carried out with 6 M hydrochloric acid. The leaching liquor is first contacted with Amberlite LA-2 which extracts the gallium and iron. The iron is then precipitated with sodium hydroxide, while gallium remains in solution. Gallium is extracted selectively from the base solution with LIX 54; the resulting stripped solution contains 83% of the gallium present in the leaching liquor. A flow diagram for this dual-extraction process is proposed. © 1997 ISWA

Continuous extraction of penicillin G by an emulsion liquid membrane in a countercurrent extraction column

Penicillin G was continuously extracted by an emulsion liquid membrane (ELM) using Amberlite LA-2 as a carrier and ECA 4360J as a surfactant in a countercurrent extraction column of Oldshue-Rushton type. The effects of various operating conditions on the extraction were experimentally investigated and discussed on the basis of our previous work on batch extraction of penicillin G. In addition, we calculated the relative interfacial area using holdup of emulsion phase in the column which was measured throughout the experiments, and it was known that the magnitude of relative interfacial area had a main influence on degree of extraction. About 90% of penicillin G was extracted under specific conditions, which verified the possibility of applying the extraction of penicillin G using an ELM to a continuous process.

Elimination of sulfate interferences in the chromatographic determination of o-phosphate using liquid-liquid extraction.

A liquid-liquid extraction procedure for the elimination of high levels of sulfate is described. The proposed method allows the ion-chromatographic determination of ppb concentrations of phosphate in the presence of a 20 000-fold excess of sulfate. The liquid anion exchange resin Amberlite LA-2 was selected to retain sulfate from the sample solution acidified by acetic acid as well as cation-exchange cartridges in the H-form. The detection limit for phosphate was 0.03 mg/L.

Extractive ultrafiltration for the removal of valeric acid

The removal of valeric acid (pentanoic acid) from aqueous solutions in the range of 0.01 to 0.7 wt%, using amines (Alamine 336 and Amberlite LA-2) and tributyl phosphate at 25°C as extractants, was carried out by extractive ultrafiltration, a combination of solvent extraction and membrane filtration. Several diluents were used in the preliminary solvent extraction tests. A tubular, ceramic, ultrafiltration membrane was used in all the membrane filtration experiments. Extraction results showed that Amberlite LA-2 and tributyl phosphate are the best extractants from those tested, but only the system with the amine shows a high degree of extraction, when using the extractive ultrafiltration technique. A more detailed study of the extractive ultrafiltration of valeric acid with Amberlite LA-2 in toluene as diluent was carried out. Permeation rates and extraction behaviour were studied under the following conditions: at total recirculation, with permeate removal and continuous operation of the system.

Distribution equilibrium of penicillin G between water and organic solutions of Amberlite LA-2

Equilibrium studies on the distribution of penicillin G between aqueous solutions and Amberlite LA-2 (a secondary amine) in mixtures of n-butyl acetate and kerosene were made in the temperature range 288–308 K. Experiments were performed as a function of aqueous pH, penicillin G concentration in the aqueous phase, and amine concentration in the organic phase. The composition of the complex present in the organic phase and the equilibrium constant for the formation of this complex were numerically determined at different temperatures. In addition, the apparent enthalpy and entropy for complexation reaction were calculated.