Study on rosmarinic acid separation by synergic extraction

Separation of rosmarinic acid by synergic reactive extraction using a mixture of two extractants (one of aminic and one of basic type) dissolved in solvents with different polarities has been studied. By analysing the influences of the main factors (organic phase polarity, extractant concentration in the mixture) on the synergic effect, the most important synergic effect (C_S = 10.89) was found to correspond to the extractants mixture containing 5 g/l D2EHPA and 5 g/l Amberlite LA-2 dissolved in n-heptane. In this system the extraction constant reached the maximum value of 6.78 l²/mol².     

Comparative Study on Reactive Extraction of Nicotinic Acid with Amberlite LA‐2 and D2EHPA

Abstract

The comparative study of reactive extraction of nicotinic acid with Amberlite LA‐2 and D2EHPA in three solvents with different polarity indicated that the extractant type and solvent polarity control the extraction mechanism. Thus, the reactive extraction with Amberlite LA‐2 in low‐polar solvents occurs by means of the interfacial formation of an aminic adduct with 3 or 2 extractant molecules. If solvents with higher polarity are used, each reactant participates with one molecule to the interfacial reaction. The mechanism of reactive extraction with D2EHPA involves in all cases the formation of a salt as the product of the interfacial reaction between one molecule of each reactant.     

二（2-乙基己基）磷酸/磷酸三丁酯复合萃取剂协萃对氨基苯甲酸

为强化两性官能团化合物的萃取分离性能,以对氨基苯甲酸（PABA）为被分离溶质,二（2-乙基己基）磷酸（D2EHPA）/磷酸三丁酯（TBP）/正庚烷的混合物为萃取剂进行了萃取平衡特性的研究,考察了溶液的pH值、D2EHPA浓度、TBP浓度对于萃取平衡的影响,建立了复合萃取剂协同萃取PABA的萃取平衡分配系数的表达式.结果表明,D2EHPA/TBP/正庚烷复合萃取剂萃取PABA具有明显的协萃效应,协萃机理为D2EHPA及TBP分别与PABA的Lewis碱性官能团（—NH2）和Lewis酸性官能团（—COOH）缔合形成亲油性更强的萃合物,且D2EHPA与TBP的浓度差异越小,协萃效应越明显.根据萃取平衡分配系数表达式拟合求取了表观萃取平衡常数,复合萃取剂的值远大于D2EHPA、TBP单独作为萃取剂的值,进一步证明了本文提出的协萃机理.     

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     

三烷基胺与二（2-乙基己基）磷酸协同萃取对氨基苯酚

引　言随着现代工业的发展及环境保护标准的严格实施 ,对极性有机物稀溶液的分离和工业废水的治理提出了更高的要求 ,而萃取技术在该领域已进行了较为广泛的研究 ,并进行了工业应用 .由于废水体系的复杂性 ,尤其是含多官能团的极性有机物废水 ,在采用萃取方法进行废水预处理时强化萃取能力是十分必要的 .自 195 6年Blake[1] 提出协同萃取以来 ,由于它兼具物理萃取和化学萃取的优点 ,具有更高的选择性和高效性 ,已成功地用于金属的萃取分离中 .协同萃取用于极性有机物稀溶液的分离多见于物理萃取 ,例如乙酸丁酯与苯乙酮协萃苯酚[2 ] 、乙酸…     

二(2-乙基己基)磷酸萃取L-色氨酸

以二 (2 -乙基己基 )磷酸 (D2EHPA) -正辛烷 (体系A)及D2EHPA -正辛醇 +正辛烷 (体系B)萃取L -色氨酸为对象 ,研究了D2EHPA浓度、L -色氨酸初始浓度、稀释剂组成以及pH值对萃取平衡分配系数的影响 .结果表明 ,在实验研究涉及的pH值 (1.0     

Enantioselective Extraction of Racemic Mandelic Acid by Di(2‐ethylhexyl) Phosphoric Acid and Tartaric Acid Derivatives as Mixed Complex Chiral Selectors

The distribution behavior of mandelic acid (MA) enantiomers was examined in a two‐phase system containing di(2‐ethylhexyl) phosphoric acid (D2EHPA) with two tartaric acid derivatives as complex chiral selectors in n‐octanol. Factors affecting the extraction were investigated, including the structure and concentration of tartaric acid as well as the concentration of D2EHPA and D,L‐MA. The results showed that both the distribution ratio and enantioselectivity were greatly improved by using a complex chiral selector rather than using the tartaric acid derivative by itself. Finally, it was found that the formation of mixed complex chiral selectors by mixing two tartaric acid derivatives with D2EHPA can improve the capacity of enantioselective extraction.     

Analysis of the Interaction between Organophosphorus Acid and Tertiary Amine Extractants in the Binary Mixtures by Fourier Transform Infrared Spectroscopy (FT-IR)

In the synergistic solvent extraction of rare earth elements by binary mixtures of organophosphorus acid and tertiary amine extractants, the extraction reaction depends on the nature and strength of the interaction between the two extractants in the mixtures. In order to correlate qualitatively the interaction in different mixtures, the FT-IR spectra for organophosphorus acid (D2EHPA, PC88A, and Cyanex 272) and tertiary amine (Alamine 336 and TEHA) extractants and their mixtures have been analyzed. The primary focus was on investigating the changes in the characteristic functional groups of acidic and amine extractants in the binary mixtures as the strength and concentration of these extractants varied. IR spectroscopy of the organics confirmed the interaction in the binary mixtures, and strength of the interaction increased with the increase in the acidity of acidic extractant and the basicity of the amine extractant.     

Extraction and Stripping Behavior of Iron (III) from Phosphoric Acid Medium by D2EHPA Alone and Its Mixtures with TBP/TOPO

In the present study an attempt has been made to understand the extraction and stripping behavior of iron (III) with D2EHPA alone and its mixture with TBP or TOPO in phosphoric acid medium. Effect of variables such as concentrations of iron (III), phosphoric acid, and phosphate in the aqueous phase, D2EHPA, TBP, and TOPO concentrations in the organic phase and temperature on the extraction process has been studied. The extraction of iron (III) decreased with increase in phosphoric acid concentration. The increase in D2EHPA concentration increased the extraction of iron (III). The presence of TOPO or TBP with D2EHPA showed antagonism. The increase in temperature decreased the extraction of iron (III) with D2EHPA alone and its mixture with either TOPO or TBP showing the exothermic nature of the extraction reaction. The stripping of iron (III) by various reagents followed the order: oxalic acid > phosphoric acid > hydrochloric acid > sulphuric acid > mixture of sulphuric and hydrofluoric acids > ascorbic acid > citric acid irrespective of extraction systems. Higher temperature favors the stripping. The effect of diluents on iron (III) extraction has also been studied. The mechanism of extraction has been explained in the light of the results obtained.     

Study on Facilitated Pertraction of Folic Acid in Pseudosteady-State Regime

The influences of the pH-gradient between the feed and stripping phases and of carrier concentration inside the membrane phase on the efficiency of facilitated pertraction of folic acid with Amberlite LA-2 in pseudosteady-state mode have been analyzed. The experiments have been carried out using a U-shaped pertraction cell which allowed to easily maintaining the liquid membrane between the two aqueous phases. On the basis of the experimental data and theoretical investigation on pseudosteady-state regime, two models describing the acid accumulation inside the liquid membrane by means of the permeability factor have been developed for two pH-values of feed phases (5.2 and 3, respectively). The proposed models offer good concordance with the experimental data and can be useful for facilitated pertraction optimization.     

Solvent extraction modeling of Ce/Eu/Y from chloride media using D2EHPA

End-of-life fluorescent lamps are becoming essential in the rare earths (REEs) field and suppose a feasible secondary source for getting them, reducing thus their supply risk. Considering the proved viability of the cationic extractants, the present study aims at establishing a solvent extraction model using di-(2-ethylhexyl)phosphoric acid (D2EHPA) not only based on the individual Ce, Eu, and Y behavior in chloride media, but also bearing in mind the competitive extraction of these metals in Ce/Eu/Y mixtures, depending on the media variables. Furthermore, the model allow determining the optimal REEs separation conditions. The results disclose that Y could be separated from the mixture using 0.1 mol/L D2EHPA, acidity above of 3 mol/L of protons and chloride concentrations higher than 4 mol/L.     

Synergistic Effect of D2EHPA and Cyanex 272 on Separation of Zinc and Manganese by Solvent Extraction

The effect of bis-2-ethylhexylphosphoric acid (D2EHPA), bis (2,4,4-trimethylpentyl) phosphinic acid (Cyanex 272), and tri-butyl phosphate (TBP) and their mixtures in various proportions for the separation and extraction of zinc and manganese from sulfate solutions were investigated. Experiments were carried out in the pH range of 0.5–5.0 at 25, 40, and 60°C. It was shown that the extraction of zinc and manganese by D2EHPA and/or Cyanex 272 can be increased by the increase in pH and temperature. The synergistic extraction and separation of zinc and manganese with a mixture of D2EHPA and Cyanex 272 was studied and the results showed that mixing the two extractants improved the extraction capacity of the mixture. Increasing the D2EHPA to Cyanex 272 ratio in the organic phase, caused a right shifting of extraction isotherms of manganese and zinc; shifting the manganese curve was more than zinc. The manganese curve had considerable right shifting with 5% D2EHPA and 15% Cyanex 272. TBP did not affect the zinc (Zn) and manganese (Mn) extraction. The stoichiometric coefficients of Zn and Mn were determined with 20% and 5% D2EHPA and 15% Cyanex 272 by applying the slope analysis method. The organic phase was stripped by sulfuric acid.     

二（2-乙基已基）磷酸萃取氨基苯甲酸的平衡特性

A series of extraction equilibrium experiments for aminobenzoic acid with di(2-ethylhexyl)phosphoric acid (D2EHPA) dissolved in n-octane or 1-octanol was carried out. The effects of aminobenzoic acid concentration,D2EHPA concentration and pH on the distribution ratio were discussed in detail. The infrared spectra of the organic phase loaded with solute illustrated that pH had little effect on the structure of the complex formed. There proceed ion association and cation-exchange.reaction in the extraction. An expression of the equilibrium distribution was proposed.     

Distribution Behavior of Amino Acid by Extraction with Di(2-ethylhexyl) Phosphoric Acid

Abstract

The distribution equilibrium of l-tryptophan (l-Trp) by extraction with di(2-ethylhexyl) phosphoric acid (D2EHPA) dissolved in n-hexane was studied. The effects of L-Trp and D2EHPA concentrations, pH, and ionic strength, particularly of L-Trp loading in the organic phase, on extraction equilibrium were examined in detail. When the amino acid loading ratio (the molar concentration ratio of the equilibrium amino acid in the organic phase to the initial dimeric D2EHPA) was less than 3 × 10^?3, one L-Trp molecule was extracted by forming a complex with four monomeric D2EHPA molecules, and the extraction equilibrium constant (K _e) was determined to be 0.045 dm³/mol. Above this loading ratio the equilibrium formula did not hold, and the apparent equilibrium constant (K _a) increased significantly with increasing loading ratio. The phenomenon was explained by taking into account two parallel reactions in which fewer D2EHPA molecules, two and one respectively, were needed to extract one l-Trp molecule.     

Reactive solvent extraction of amino acids with cationic extractants

A mixture of amino acids (arginine, phenylalanine, alanine, glycine and aspartic acid) in solution was extracted by four acidic extractants (dinonylnaphthalenesulphonic acid (DNNSA), di(2-ethylhexyl)monothiophosphoric acid (D2EHPA(S)), di(2-ethylhexyl)phosphoric acid (D2EHPA) and Versatic 10) in toluene. The extractive capacity of the organic phase for the amino acids, using DNNSA, D2EHPA(S) and D2EHPA was found to decrease in the order arginine>phenylalanine>alanine>glycine>aspartic acid, although at low pH values phenylalanine>arginine occurred for D2EHPA(S) and D2EHPA. Separation factors derived for pairs of amino acids were in the range 2·0 (glycine–aspartic acid) to 20·1 (alanine–glycine). The extractive and loading capability of the extractants for the amino acids was found to decrease in the order DNNSA>D2EHPA(S)>D2EHPA>Versatic 10, which follows the reverse order of their respective acid dissociation constants. DNNSA was shown to be a promising extractant for the extraction and fractionation of amino acids. © 1998 SCI     

Solvent Extractive Separation of Zirconium and Hafnium from Hydrochloric Acid Solutions by Organophosphorous Extractants and Their Mixtures with Other Types of Extractants

From 1 to 4 M HCl medium, zirconium was selectively extracted over hafnium by organophosphorous extractants (D2EHPA, PC88A, Cyanex 272). In order to increase the separation factor Zr/Hf, mixtures of organophosphorous extractants with amines (Alamine 336, Aliquat 336) or cationic extractants (Versatic acid 10, LIX 63) were employed in 1–4 M HCl medium. Mixtures with Versatic acid 10 and LIX 63 led to depression in the extraction percentages. But the mixture with LIX 63 was found to be the most effective in separating the two metals among the extractant systems tested in this study. The highest separation factor of around 9.5 was obtained with a mixture of 0.01 M LIX 63 + 0.05 M Cyanex 272 at HCl concentration of 2–4 M. The Zr and Hf were effectively stripped from the loaded mixture of LIX 63 + Cyanex 272 by sulfuric acid solution.     

Solvent extraction reaction of hafnium(IV) from strong sulfuric acid solutions with D2EHPA and PC 88A

Hafnium can be selectively extracted over zirconium from strong sulfuric acid solutions by D2EHPA or PC 88A. Solvent extraction experiments have been performed to identify the reaction of Hf from strong sulfuric acid solutions (1 to 7 M) by these two extractants. Hafnium extraction was gradually decreased and then increased again with the increase of sulfuric acid concentration. By applying a slope method, the extracted Hf species was proposed to be HfA₄·(HA)₂ by D2EHPA and Hf(HSO₄)₂A₂·(HA)₂ by PC 88A, respectively. This difference in the nature of the extracted species was verified by FT-IR spectra.     

有机磷(膦)酸萃取钴和镍的动力学行为比较

依据实验结果和文献数据讨论了有机磷酸类萃取剂萃取钴及镍的动力学行为.结果表明,有机磷酸酸性强,溶入水相的速度快,则萃取速度亦快,钴和镍的萃取速度差异由溶剂交换速度决定.     

Effect of a water-insoluble organic acid on amine extraction of acetic acid from aqueous solutions. Equilibrium studies

The effect of a water-insoluble organic acid, di(2-ethylhexyl)phosphoric acid (D2EHPA), on the extraction equilibrium of acetic acid from aqueous media with xylene solutions of tri-n-octylamine (TOA) was systematically investigated. In the absence of D2EHPA, the formulation of the extracted species in the organic phase and equilibrium constants for the formation of these species were numerically determined. Synergistic and antagonistic effects on the extraction of acetic acid were observed in the presence of D2EHPA, mainly depending on the concentration of TOA and the concentration ratio of D2EHPA to TOA. Finally, the influence of temperature on the extraction of acetic acid with TOA and/or D2EHPA was investigated.     

Extraction Equilibria of 4-Hydroxypyridine using Di (2-ethylhexyl) Phosphoric Acid

Extractions of 4-Hydroxpyridine (4HP) from aqueous solutions using Di(2-ethylhexyl)phosphoric acid (D2EHPA) as extractant in 1-octanol and kerosene were studied. The factors that affected the distribution coefficient (D), such as equilibrium pH, the concentration of D2EHPA, and the type of diluents were discussed. The interaction mechanism between 4HP and D2EHPA was validated by infrared spectroscopic analysis. D increased with the increase of the concentration of D2EHPA and peak values appeared at equilibrium pH = 3.6–5.0. D in the polar diluent (1-octanol) was much higher than those in the non-polar diluent (kerosene). The extraction reaction was found to be a proton-transfer process and D2EHPA mainly reacted through its –OH with –N– of 4HP. The apparent reactive extraction equilibrium constants K ₁₁ and K ₁₂ were obtained by fitting the experimental data of extraction equilibrium. By comparing calculated D values from the proposed model with the experimental ones, the accuracy of the proposed model was examined.