Reactive extraction of itaconic acid using tri‐n‐butyl phosphate and aliquat 336 in sunflower oil as a non‐toxic diluent

Itaconic acid finds a place in various industrial applications. It can be produced by biocultivation in a clean and environment friendly route but recovery of the acid from the dilute stream of the bioreactor is an economic problem. Reactive extraction is a promising method to recover carboxylic acid but suffers from toxicity problems of the diluent and extractant employed. So there is need for a non‐toxic extractant and diluent or a combination of less toxic extractants in a non‐toxic diluent that can recover acid efficiently. Effect of different extractants: tri‐n‐butylphosphate (TBP) (an organophosporous compound) and Aliquat 336 (a quaternary amine) in sunflower oil was studied to find the best extractant–sunflower oil combination. Equilibrium complexation constant, K_E, values of 1.789 and 2.385 m³ kmol^?1, respectively, were obtained for itaconic acid extraction using TBP and Aliquat 336 in sunflower oil. The problem of toxicity in reactive extraction can be reduced by using a natural non‐toxic diluent (sunflower oil) with the extractant. Copyright © 2010 Society of Chemical Industry     

Study of lactic acid extraction with higher molecular weight aliphatic amines

Lactic acid extraction was studied with two extractants, trioctyl amine (TOA) and Aliquat 336, in three diluents (methylisobutyl ketone (MIBK), octanol and paraffin liquid). The effects of organic phase extractant concentration and aqueous phase pH on the extraction process were examined. Among the extractants, TOA was found to be a better extractant than Aliquat 336 in all the diluents. In experiments with 50% (v/v) TOA in methylisobutyl ketone, 79% lactic acid could be extracted (initial lactic acid concentration 86·96 g dm⁻³). MIBK had a profound effect on the extraction behaviour of TOA in comparison with octanol and paraffin liquid while none of the diluents affected the extraction with Aliquat 336. The extraction of lactic acid was favoured at low pH. The toxicities of TOA and the diluents to Lactobacillus rhamnosus NRRL B445 were also studied. While TOA was found to be highly toxic at the molecular and the phase level, the paraffin liquid was totally non-toxic. The extraction of glucose and yeast extract by TOA and the diluents used was found to be low, which thus enables the selective extraction of lactic acid. © 1998 SCI     

Parametric optimization of green synergistic reactive extraction of lactic acid using trioctylamine,Aliquat336, and butan-2-ol in sunflower oil by response surface methodology

A novel green synergistic reactive extraction technique for the removal of lactic acid (LA) from aqueous solution was explored. Response surface methodology (RSM) was applied to optimize the process variables for LA synergistic reactive extraction using a mixture of trioctylamine and Aliquat336 as extractants. During this present investigation, 2-butanol and sunflower oil were used as organic and green diluent. Systematic investigation has been carried out to obtain the optimum process conditions viz. initial LA concentration, pH of aqueous solution, extractant ratio, extractant concentration, solvent ratio, phase ratio, temperature, stirring speed, and contact time for maximizing the LA distribution coefficient (K_D) and extraction efficiency (%, η). The highest experimentally achievable LA distribution coefficient (K_D) and extraction efficiency (%) at optimized process conditions were found to be in close agreement with those predicted by numerical optimization using RSM. Thus, the results of present finding have been shown a great ability of sunflower oil as an economic and environmentally friendly green solvent for LA extraction.     

Valeric acid extraction with tri‐n‐butyl phosphate impregnated in a macroporous resin: II. Studies in fixed bed columns

Extraction and back‐extraction of valeric acid in a fixed bed packed with Amberlite XAD‐4 resin impregnated with tri‐n‐butyl phosphate were experimentally studied at 25 °C. The effects of the feed flow rate, acid concentration in the feed solution and extractant concentration in the impregnated resin on the breakthrough curves, were investigated. The bed saturation capacity was larger under the conditions of higher extractant concentration in the resin phase and higher acid concentration in the feed solution. A dynamic model that considers intraparticle diffusion and external liquid film diffusion as limiting steps in mass transfer rates was successfully applied. The intraparticle effective diffusivities (10^?9 dm² s^?1) were from one to three orders of magnitude lower than the diffusivities in the external liquid film (10^?8–10^?6 dm² s^?1). A fast and complete back‐extraction of valeric acid from the saturated bed was carried out with sodium hydroxide solutions. The operational life of the impregnated resin was also studied. Copyright © 2005 Society of Chemical Industry     

Efficient transport and selective extraction of Cr(VI) from waste pickling solution of the stainless steel-cold rolled plate process using Aliquat 336 via HFSLM

The selective extraction of Cr(VI) from waste pickling solution of the stainless steel-cold rolled plate process by hydrophobic hollow fiber supported liquid membrane (HFSLM) was investigated. The effects of various parameters— types of organic extractants, i.e., metyl trioctylammonium chloride (Aliquat 336), tri-n-octylamine (TOA), tri-n-butyl phosphate (TBP) and the mixture of Aliquat 336 and TBP, concentration of the selected extractant, types of stripping solutions (NaCl and NaOH), pH and concentration of the selected stripping solution, and the operating temperature—were studied. The feed and stripping solutions flowed countercurrently. The results showed that the coexisting contamination in spent pickling solution of Fe(II) and Ni(II) ions had no significant effect on Cr(VI) extraction. Among the extractants used in this study, Aliquat 336 was a specific carrier to attain the highest percentage of Cr(VI) extraction. About 70% extraction was achieved by using 0.11 M Aliquat 336 and 0.5 M NaCl at pH 7. The percentage of stripping slightly increased when the concentration of NaCl increased. In addition, it was found that the operating temperature of 20, 30, 40, and 50 °C had almost no influence on the percentages of extraction and stripping of Cr(VI). The calculated diffusion energy of Cr(VI) extraction was 15.14 kJ/mol.     

Extraction and separation of Pt(IV)/Rh(III) from acidic chloride solutions using Aliquat 336

Extraction and separation of Pt(IV)/Rh(III) from chloride solutions using Aliquat 336 (Quaternary ammonium salt made by the methylation of mixed tri octyl/decyl amine) diluted in kerosene as an extractant/synergist alone and mixed with organophosphorous extractants as synergists/extractants were carried out from an aqueous feed containing 0.0005 mol L⁻¹ Pt(IV)/Rh(III).Variation of hydrochloric acid concentration of aqueous phase from 0.005 to 10.0 mol L⁻¹ increased the percentage extraction of platinum up to 5.0 mol L⁻¹ there after it decreases. Whereas in the case of rhodium, from 0.005 to 1.0 mol L⁻¹ acid range the percentage extraction was decreased from 1.0 to 10.0 mol L⁻¹ acid range is favorable for extraction. Platinum(IV)/rhodium(III) separation factor of 279.2 was obtained at 1.0 mol L⁻¹ HCl concentration with 0.005 mol L⁻¹ Aliquat 336 and separation factor of 612.3 was obtained at 3.0 mol L⁻¹ HCl concentration with 0.01 mol L⁻¹ Aliquat 336. The present study optimized the various experimental parameters like phase contact time, effect of extractant, salts, temperature, loading capacity of extractant, stripping studies with various mineral acids/bases, recycling and reusing capacity of extractant up to ten cycles.     

NON-DISPERSIVE LIQUID EXTRACTION OF Cr(VI) BY TBP/ALIQUAT 336 USING CHITOSAN-MADE HOLLOW FIBER

ABSTRACT

TBP and alkylammonium extractants were investigated for chromate removal from dilute solutions using chitosan-made hollow fibers. Chromate is adsorbed by the chitosan fiber and simultaneously desorbed by the extractant. The influence of chromate concentration, extractant concentration, extractant volume on relative concentration deccrease were investigated as a function of time. These experimental parameters barely influenced the decrease in the relative concentration. Fiber length is more significant in the control of the extraction kinetics. In recirculation flow mode, the relative concentration can be well described as an exponential function of time. The kinetic constant varies as a linear function of fiber length. Amine extractants (Aliquat 336, Alamine 336, Amberlite LA-2) are better extractants than TBP both from the kinetics and equilibrium standpoints. With Aliquat 336 the final Cr(VI) concentration tends to zero, while with TBP, the equilibrium is controlled by the volume of the extractant.     

Hydrodynamic properties for N,N,N′,N′‐tetraalkyl diglycolamides dissolved in n‐dodecane system

N,N,N′,N′‐tetraoctyl diglycolamide (TODGA) and N,N,N′,N′‐tetra(2‐ethylhexyl) diglycolamide (T2EHDGA) have been identified as promising extractants for actinide partitioning from high‐level nuclear waste. These extractants are proposed to be used along with suitable phase modifiers, viz. N,N‐dihexyl octanamide (DHOA), tri‐n‐butyl phosphate (TBP) and 2‐decanol dissolved in n‐dodecane. Hydrodynamic parameters, viz. density, viscosity and interfacial tension (IFT) are important for optimisation of hydrometallurgical process to ensure that there is no emulsion formation and to achieve desired phase disengagement rate. Densities and viscosities of the two extractants, viz. TODGA and T2EHDGA along with different phase modifiers have been measured over different range of compositions and temperatures (298–333 K). The viscosity data have been used to calculate the activation energy for viscous flow for each composition of solvents. The IFT values have also been measured for different solvent compositions. The viscosity and IFT data of TODGA and T2EHDGA with 2‐decanol as phase modifier appears suitable under hydrometallurgical conditions proposed for actinide partitioning. © 2011 Canadian Society for Chemical Engineering     

Organic media selection for the extraction of β‐hydroxyisobutyric acid produced by microbial biotransformation

The aim of this work is to evaluate both the toxic effect of different organic media on the stereospecific oxidation of 2‐methyl‐1,3‐propanediol to R‐(−)‐β‐hydroxyisobutyric (HIBA) in two‐phase systems and the extraction ability and selectivity of these non‐water miscible phases. Apart from traditional solvents, specific organic acid‐complexing carriers like TOPO, TOA and Aliquat 336 dissolved in different diluents have been studied. Special interest has been focused on the effect of the concentration of the organic phase extractants and the pH of the aqueous phase on the extraction system. TOPO dissolved in isooctane enabled higher K_p values at lower concentrations to be attained and resulted in lower toxicity, but its extractive capacity is strongly dependent on the pH. Our results suggest that using a compromise pH value between optimum for bioconversion and extraction, TOPO dissolved in isooctane can be successfully used as an extractive phase for HIBA production in a two‐phase system. © 2000 Society of Chemical Industry     

Computer simulation of flow‐sheets for the solvent extraction of uranium: a new route to delay the effect of chemical degradation of the organic phase during uranium recovery from acidic sulfate media

BACKGROUND: The extractants used in solvent extraction processes undergo degradation under thermal, chemical and radiolytical stresses. In the case of uranium plants, tri‐n‐octylamine, used as an extractant, slowly degrades into di‐n‐octylamine. Such degradation causes a gradual depletion of the uranium extraction isotherms and as a result, of the efficiency of uranium recovery from feed solutions. The present work highlights a new route to delay this depletion of the extraction efficiency, merely by optimizing the flow‐sheets involved in the process. Five flow‐sheets have been compared for uranium recovery from acidic sulfate media by a solution of 0.146 mol L⁻¹ tri‐n‐octylamine in kerosene modified with 5% w/w 1‐tridecanol and stripping with a 199 g L⁻¹ Na₂CO₃ solution. These five flow‐sheets include the classical counter‐current flow‐sheet with four mixers–settlers in extraction and three mixers–settlers in stripping and four unusual combined solvent extraction flow‐sheets with two independent extraction stripping loops and with one or two feed inlets. RESULTS: Computer simulation supplied evidence of the strong influence of the studied flow‐sheets on the sturdiness of the process. More precisely, the unusual combined solvent extraction flow‐sheets appeared to be significantly more efficient than the classical counter‐current one and it is shown that an advantage of this can be to delay the negative impact of gradual degradation of tri‐n‐octylamine on uranium recovery efficiency from acidic sulfate media. CONCLUSION: The replacement of classical counter‐current flow‐sheets with a unique extraction‐stripping loop in unusual combined flow‐sheets with two or more independent extraction‐stripping loops and with one or more feed inlets is a fruitful approach to delay the periodic addition of fresh tri‐n‐octylamine necessary for counter‐balancing the progressive degradation of the extraction solvent and, as a result, to delay the gradual depletion of the efficiency of uranium recovery. Copyright © 2009 Society of Chemical Industry     

VARIATIONS IN THE SOLVENT EXTRACTION BEHAVIOR OF BIFONCTIONAL PHOSPHORUS-BASED COMPOUNDS MODIFIED WITH TBP

ABSTRACT

The solvent extraction of americium from nitric acid by several modified bifunctional extractants in CCl₄has been investigated. For all the compounds examined, addition of a modifier such as tributylphosphate (TBP) enhances distribution ratios at high aqueous acidities. The effect of the modifier at lower acidities varies depending on the basicity of the bifunctional extractant. While the most basic extractants show significantly reduced distribution ratios from lower acid solutions upon TBP addition, for the less basic compounds only slight reductions or, in some cases, even moderate increases in extraction are observed. Studies of the effect of modifier basicity on extraction behavior have also been carried out. The changes in distribution ratios with modifiers fall within the range of variations observed for diluent effects with extractants of this type. Increases in high acid distribution ratios upon TBP addition to an extractant as simple as trioctylphosphine oxide indicate that this modification of extraction behavior may be of general use for a wide range of neutral extractants     

Sensitive Colorimetric Detection of Explosive 2,6‐Bis(picrylamino)pyridine after Preconcentration by Dispersive Liquid‐Liquid Microextraction

An experimental investigation for sensitive spectrophotometric detection of explosive, 2,6‐bis(picrylamino)pyridine (BPAP) using dispersive liquid‐liquid microextraction was carried out. Based on this procedure, which is a dispersive‐solvent‐free technique, the extractant is dispersed in the aqueous sample solution using Aliquat 336 (acted as disperser agent and carrier to extraction solvent) and monitored with microvolume UV/Vis spectrophotometer. The effect of different variables such as pH, concentration of sodium hydroxide, type and volume of extraction solvent, concentration of Aliquat 336 solution and coexisting substances were systematically investigated and optimized. Interference tests showed that the developed method has a good selectivity and could be used conveniently for determination of explosive analyte. The proposed method is capable of determining BPAP over a range of 2.0–150.0 ng mL⁻¹ with a limit of detection 1.0 ng mL⁻¹. Relative standard deviations (RSD) for 20.0 and 80.0 ng mL⁻¹ of BPAP were 3.3 and 1.2 % (n=10), respectively. This colorimetric method was applied to determine BPAP in different water and soil samples.     

Intensification of Nicotinic Acid Separation using Organophosphorous Solvating Extractants by Reactive Extraction

Nicotinic acid (3‐pyridine carboxylic acid) is widely used in food, pharmaceutical, and biochemical industries. Compared to chemical methods, enzymatic conversion of 3‐cyanopyridine is an advantageous alternative for the production of nicotinic acid. This study is aimed to intensify the recovery of nicotinic acid using reactive extraction with organophosphorus solvating extractants such as tri‐n‐octyl phosphine oxide (TOPO) and tri‐n‐butyl phosphate (TBP). The distribution of nicotinic acid between water and phosphorus‐based solvents dissolved in various diluents and the comparison of extraction efficiency with pure diluents are studied at isothermal conditions. Pure diluents are not found to be good extracting agents and the maximum distribution coefficient (K_D) obtained with 1‐octanol is 0.31. Experimental studies are carried out to investigate the effect of diluent, initial acid concentration, extractant type, and extractant composition on the degree of extraction. The maximum recovery of nicotinic acid is obtained by dissolving TOPO in MIBK at an initial nicotinic acid concentration of 0.10 kmol/m³. Solvation numbers and extraction equilibrium are also estimated with both TBP and TOPO.     

Rates of acetate extraction from simulated waste streams in chloromycetin production

The kinetics for extraction recovery of acetate ions from simulated waste streams in chloromycetin production by Aliquat 336 (a quaternary amine) and tri‐n‐butylphosphate (TBP) in xylene were examined using a microporous membrane‐based stirred cell. The waste stream typically contained 15.4% acetic acid, 8.8% sodium acetate, and 4.7% (w/w) NaCl. The stirred cell could give intrinsic rates for formation of the complex occurring at or near the organic–aqueous interface. It was shown that the extraction rate with TBP was higher than that with Aliquat 336. The effect of temperature (288–318 K) on the reaction rate with TBP was also examined and the activation energy (54.5 kJ mol⁻¹) was obtained. © 1999 Society of Chemical Industry     

Synthesis of n‐butyl phenyl ether by tri‐liquid‐phase catalysis using poly(ethylene glycol)‐600 as a catalyst – analysis of factors affecting the reaction in a batch reactor

As the second part of a series of studies on the synthesis of n‐butyl phenyl ether (ROPh) by tri‐liquid‐phase catalysis, this work examines the factors affecting the reaction between n‐butyl bromide (RBr, organic substrate) and sodium phenolate (NaOPh, aqueous nucleophile) with poly(ethylene glycol)‐600 (PEG‐600) as a phase‐transfer catalyst. The reaction is performed in a batch reactor at 45–85 °C for 2 h while the agitation speed is fixed at 1000 rpm. Experimental results indicate that the individual mole fractions of NaOPh and PEG‐600 slightly affect the reaction, while the total amount of these components exerts significant influence. When the mole fraction of PEG‐600 is 0.5, the reaction rate and the conversion of RBr are the highest. No byproducts are formed in the course of the reaction. The system using a non‐polar organic solvent might obtain a higher conversion compared with a weakly polar one owing to a higher concentration of PEG‐600 in the third liquid phase. Furthermore, adding NaOH facilitates the reaction to obtain a higher reaction rate than adding other kinds of salt because the addition of a base results in the formation of a third liquid phase. The catalytic ability of PEG with average molecular weight of 600 gmol^?1 is far higher than that with average molecular weight of 200, 400 and 1000 because PEG‐600 possesses an appropriate chain length which can tightly associate with Na⁺ to form the complex of PEG‐600‐Na⁺OPh^? for reacting with RBr. In addition, this nucleophilic substitution reaction is found to be pseudo‐first‐order with respect to RBr. © 2001 Society of Chemical Industry     

Influence of Solvent Polarity on the Mechanism and Efficiency of Formic Acid Reactive Extraction with Tri‐n‐Octylamine from Aqueous Solutions

The reactive extractions of formic acid with tri‐n‐octylamine (TOA) dissolved in three solvents with different dielectric constants (dichloromethane, butyl acetate, n‐heptane) without and with 1‐octanol as phase modifier were comparatively analyzed. The results indicated that the mechanism of the interfacial reaction between acid and extractant (Q) is controlled by the organic phase polarity. In the absence of 1‐octanol, the structures of the extracted complexes are (HA)₂Q₂ for dichloromethane and butyl acetate, and (HA)₂Q₄ for n‐heptane. These structures are modified by adding 1‐octanol and become (HA)₂Q for extraction in dichloromethane or butyl acetate, and (HA)₂Q₂ for extraction in n‐heptane. Although the presence of 1‐octanol improves the extraction efficiency, it leads to a reduction of the extraction constants for all considered solvents, an influence that is more significant for n‐heptane.     

Synergistic Solvent Extraction and Transport of Zn(II) and Cu(II) across Polymer Inclusion Membranes with a Mixture of TOPO and Aliquat 336

Separation of zinc(II) and copper(II) ions from aqueous solutions by synergistic extraction and transport through polymer inclusion membranes (PIMs) has been investigated. A mixture of trioctylphosphine oxide (TOPO) and trioctymethylammonium chloride (Aliquat 336) was used as a selective extractant as well as an ion carrier in polymer membranes. The effects of hydrochloric acid concentration in the aqueous phase and extractants concentration in the organic phase on the separation process of zinc(II) and copper(II) ions have been studied. Zn(II) ions were successfully separated from Cu(II) ions in solvent extraction process using 0.025 M TOPO and 0.06 M Aliquat 336 in kerosene. Polymer inclusion membranes (PIMs) containing a mixture of TOPO and Aliquat 336 as the ion carrier have been prepared and the facilitated transport of Zn(II) and Cu(II) ions has been studied. The influence of membrane composition on the transport kinetic of Zn(II) and Cu(II) has been evaluated. Zn(II) ions were preferably transported from the aqueous solutions containing Cu(II) and above 87% of Zn(II) ions were effectively recovered from the 0.5 M HCl solution as the source phase through PIM into 0.5 M H₂SO₄ as the stripping phase.     

The Extraction and Separation of Ho,Y, and Er(III) with the Mixtures of Cyanex 302 and Another Organic Extractant

Abstract

The extraction and separation of Ho, Y, and Er(III) with the mixtures of bis(2,4,4‐trimetylpentyl)monothiophosphinic acid (Cyanex 302) and another organic extractant, such as acidic organic extractant (di‐2‐ethylhexyl phosphoric acid P204, 2‐ethylhexyl phosphoric acid mono‐2‐ethylhexyl ester P507, di‐2‐ethylhexyl phosphinic acid P229, and sec‐nonylphenoxy acetic acid CA‐100), neutral organic extractant (tri‐n‐butyl phosphate TBP, di‐(1‐metylheptyl)metyl phosphate P350, and branched trialkylphosphinic oxide Cyanex 925) or primary amine N1923, has been investigated in this paper. The extractability and separation ability for the Ho, Y, and Er with the mixtures of Cyanex 302 and organic extractants has been compared. The synergistic effect of the Ho, Y, and Er extraction with the mixtures of Cyanex 302 and P229, Cyanex 925, CA‐100, or N1923 has been explored and the synergistic enhancement coefficients have been calculated. At last, the Y³⁺ synergistic extraction with the mixtures of Cyanex 302 and CA‐100 has been determined and the extracted complex has been deduced.