三辛胺萃取分离苹果酸的特性

为探讨有机羧酸的成键机理，以二元有机酸－苹果酸为分离溶质，实验测定了三辛胺（TOA）在正辛醇、甲基异丁基酮（MIBK）和氯仿三种稀释剂中萃取苹果酸的平衡及负载溶剂红外光谱特性，结果表明，TOA浓度，稀释剂种类对萃取平衡的影响与苹果酸的浓度有关；平衡水相酸的浓度较低时，萃取剂可提供较大的萃取能力，TOA的化学计量饱和后，存在“过载”现象，且过载量为MIBK＞正辛醇＞氯仿，TOA萃取苹果酸的萃合物主要为酸胺比为（2：1），（1：1）和（1：2）等三种形式，其中（1：2）萃合物中苹果酸与TOA之间的结合一个是离子对成盐，一个是氢键缔合，同时，以质量作用定律为基础，建立了描述萃取平衡的数学模型，求得了相应的反应萃取平衡常数K11，K12，K21。     

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     

Extraction and Separation of Cadmium and Zinc with a Mixture of Di-(2-Ethylhexyl)- Dithiophosphoric Acid and Trioctyl Amine

The extractlon of cadmium and zinc with di-(2-ethylbexyi)-dithiophosphoric acid(D2EHDTPA)-toluene and D2EHDTPA-trioctyl amine(TOA)-toiuene has investiated. in-frared spectrum analsis,the nuclear magnetic resonance spectrum(NMR) analysis and conductivity measurements confirm that the probable structures of the extracted complexes are CdA2 and ZnA2, Cadmium can be extracted by D2EHDTPA very eui]y. Almost all the cadmium can be extracted, but stripping of cadmium from the organic phase is very difficult. When a mLxture of D2EHDTPA and TOA is used, selective extraction of cadmium from zinc sulfate solution can be achieved. Cad-mium can be easily stripped from the organic phase.     

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     

Extraction of Amino-J Acid from Waste-water by Emulsion Liquid Membrane

The emulsion liquid membrane technique was used to extract amino-J acid from industrial dye waste-water. The effects of stirring speed, ratio of the emulsion to water (Rew), ratio of the oil to internal phase (Roi) and membrane phase components on the extraction rate were investigated and optimized. The results showed that the extraction rate of amino-J acid approached 97% when the stirring speed was 300 r/min, Rew 1:6, Roi 1:1, trioctylamine (TOA) 3 mL/100 mL kerosene, and methyl-didecyle-alcohol-acrylate (LMA-2) 3 g/100 mL kerosene, respectively. The extraction rate had not changed with the oil phase reused for times.     

络合萃取法从稀溶液中提取草酸

为深入认识二元酸的络合萃取平衡特性及萃取机理,以三辛胺（TOA）为络合剂,正辛醇为助溶剂,煤油为稀释剂,草酸为被萃溶质,进行了混合溶剂的萃取平衡实验研究,测定了络合剂的浓度、稀释剂的组成等因素对萃取平衡分配系数的影响,并对TOA萃取草酸的机理进行了探讨。实验结果表明,随TOA浓度的增大,萃取平衡分配系数呈增大趋势;随溶质初始浓度的增大,有机相的溶质浓度向饱和萃取量接近;饱和萃取量随络合剂浓度的增大而增大;稀释剂对萃取平衡的影响与TOA浓度有关,TOA浓度较小时,煤油的加入使萃取平衡分配系数减上,TOA浓度较大时,煤油的加入对萃取平衡影响较小。     

草酸与乙醛酸的萃取分离

以草酸和乙醛酸的稀溶液为分离对象 ,采用三辛胺 (TOA)为萃取反应剂、正辛醇为稀释剂 ,研究了单溶质、双溶质有机酸的萃取分离特性 ,测定了溶液pH值、萃取反应剂的浓度等因素对双溶质有机酸萃取的影响 ,提出了萃取的化学反应发生在有机相中的假定 ,建立了TOA萃取草酸的数学模型 .实验结果表明 ,草酸与TOA的萃合物有 1∶1和 1∶2两种形式 .在本实验的条件范围内 ,草酸的分配系数较乙醛酸大 ,且随溶液pH值的增大而下降 ,草酸对乙醛酸的分离系数随pH值的增大而减小 .随萃取反应剂浓度的增大 ,两酸的分配系数皆随之增大 ,分离系数也随之增大 ,而且对于高浓度的萃取反应剂在较高的溶液pH值下草酸仍具有较大的分离系数 .采用单溶质萃取反应平衡常数及纯稀释剂中双溶质的分配系数预测双溶质萃取的结果 ,预测值与实验值相当接近     

Origin of defect-related green emission from ZnO nanoparticles: effect of surface modification

We investigated the optical properties of colloidal-synthesized ZnO spherical nanoparticles prepared from 1-octadecene (OD), a mixture of trioctylamine (TOA) and OD (1:10), and a mixture of trioctylphosphine oxide (TOPO) and OD (1:12). It is found that the green photoluminescence (PL) of samples from the mixture of TOA/OD and TOPO/OD is largely suppressed compared with that from pure OD. Moreover, it is found that all spherical nanoparticles have positive zeta potential, and spherical nanoparticles from TOA/OD and TOPO/OD have a smaller zeta potential than those from OD. A plausible explanation is that oxygen vacancies, presumably located near the surface, contribute to the green PL, and the introduction of TOA and TOPO will reduce the density of oxygen vacancies near the surfaces. Assuming that the green emission arises due to radiative recombination between deep levels formed by oxygen vacancies and free holes, we estimate the size of optically active spherical nanoparticles from the spectral energy of the green luminescence. The results are in good agreement with results from TEM. Since this method is independent of the degree of confinement, it has a great advantage in providing a simple and practical way to estimate the size of spherical nanoparticles of any size. We would like to point out that this method is only applicable for samples with a small size distribution.     

Back extraction of propionic acid from loaded organic phase

Study of back extraction and hence regeneration of the acid from the loaded organic phase is essential for the design of a complete reactive extraction process. In this paper, the backextraction of propionic acid from the loaded organic phase (tri-n-octylamine (TOA)+diluent) was studied using different techniques, like, temperature and diluent swing, using NaOH or trimethyl amine. It was found that temperature swing regeneration could result in recovery as high as 88% of acid in two stages from organic phase, TOA+MIBK. However, from TOA+alcohols, the recovery by this technique was average. Diluent swing is not successful in efficiently recovering acid from the organic phases employed. NaOH, in stoichiometric ratio, could completely recover the acid, but in the form of sodium propionate. The 100% acid recovery was accomplished using trimethylamine (TMA), when used in stoichiometric ratio slightly higher than (1:1). Along with the complete recovery acid can be easily separated from TMA as the base is volatile. Kinetics of backextraction of propionic acid using TMA was also studied and it was found to be fast.     

三辛胺萃取草酸的机理

选择草酸稀溶液为萃取对象 ,采用三辛胺 (TOA)为络合剂 ,正辛醇为稀释剂 ,开展了TOA萃取草酸的机理研究 .以红外谱图为分析手段 ,通过测定络合剂及被萃溶质的浓度对萃合物组成的影响 ,得到其萃合物以 1∶1和 1∶2 (酸 :碱 )两种形式存在于有机相中 ;并通过萃取平衡实验 ,获得了TOA萃取草酸的平衡特性 ,进一步验证了萃合物组成 .以此为基础建立了草酸与TOA两种萃合比情况下的数学模型 ,拟合求得了K₁₁及K₁₂ ,其中 1∶2萃合物的化学萃取平衡常数远远小于 1∶1的相应值     

Extraction of 2-chloroethanol from aqueous solutions by trioctylamine

The trioctylamine (TOA) with kerosene as a diluent was used to separate 2-chloroethanol from aqueous hydrochloride acid solution. The stoichiometry of complex data was studied with infrared spectroscopic and the result shows that the ratio of 2-chloroethanol to amine in the complex was 1:2. The equilibrium constant was assumed to be 4.05 × 10⁵. Effects of temperature, equilibrium pH, TOA concentration, organic phase to aqueous (O/A) phase ratio and contact time on extraction yield of 2-chloroethanol were investigated. The results show that extraction yield can reach 58.2% under the optimum conditions.     

Comparative Study on Reactive Extraction of Picolinic Acid with Six Different Extractants (Phosphoric and Aminic) in Two Different Diluents (Benzene and Decan-1-ol)

The equilibrium study on reactive extraction of picolinic acid by six different extractants (phosphoric and aminic) dissolved in two different diluents (benzene and decane-1-ol) is carried out to evaluate the performance of extractants and diluents. The extraction ability in terms of the distribution coefficient (K _D) is found to be in the order of tri-n-octylamine (TOA) ≥ tri-n-dodecylamine (TDDA) > di-2-ehylhexyl phosphoric acid (D2EHPA) > tri-n-butyl phosphate (TBP) > tri-octyl methyl ammonium chloride (Aliquat 336) > tri-n-octyl phosphine oxide (TOPO) with both diluents. Decan-1-ol is found to be the better solvating medium for the acid-extractant complexes. A mathematical model based on mass action law is employed to estimate the values of partition coefficient (P) and dimerization constant (D) in physical extraction, and equilibrium extraction constants (K _E) in chemical extraction. The values of loading ratios (Z) less than 0.5 imply the formation of (1:1) acid:extractant solvates in the organic phase. Decan-1-ol with TOA is the most effective solvation medium with K _{D, max} = 9 at 0.01 kmol · m^?3 of picolinic acid and K _E = 19.448 m³ · kmol^?1.     

EXTRACTION EQUILIBRIUM OF PHENOL BY SULFURIC ACID SALTS OF TRIOCTYLAMINE

An investigation was undertaken involving the extraction equilibrium of phenol from an aqueous solution using trioctylamine sulfate salt (TOA salt)/trioctylamine (TOA) as the extractant. The purpose of using trioctylamine as the organic solvent is to increase the total capability of phenol extraction as well as to avoid the use of other organic solvents. In order to prevent the formation of a second phase from the reaction of trioctylamine and sulfuric acid, 1-octanol in an appropriate amount was added to make the organic solution homogeneous. Equilibrium distribution coefficients (K_d) in the extraction of phenol by TOA salt/TOA were measured for various operating conditions. The equilibrium distribution coefficient of phenol (K_d) between two phases decreased with increasing the initial concentration of phenol, thereby decreasing the initial concentration of sulfuric acid, and subsequently increasing the volume ratio of aqueous phase to organic phase. We recommended that the extraction is carried out at low temperature. A higher value of K_d up to 800 was obtained in using trioctylamine sulfate/trioctylamine as the extractant for equal volume ratio of aqueous phase to organic phase.     

对羟基三甲基苯磺酸氧化废水萃取研究

三甲基氢醌是合成维生素E的重要中间体，国内企业主要采用对羟基三甲基苯磺酸，经MnO2氧化为三甲基苯醌，再加氢还原而得。本文采用三辛胺作萃取剂，在不同稀释剂作用下对氧化废水萃取回收磺化物和降低COD的研究。结果表明，萃取可有效地回收磺化物在废水相的残留并大大降低COD。     

Membrane contactor for reactive extraction of succinic acid from aqueous solution by tertiary amine

A hollow fibre membrane contactor (HFMC) made of microporous, hydrophobic, polypropylene (PP) fibres was used for removing dissolved succinic acid (SA) from aqueous streams. The Liquicel^® HFMC module was operated in the liquid–liquid extraction (LLE) mode with aqueous SA as the feed solution. The aqueous feed was prepared by dissolving measured amounts of SA in deionised water, with concentrations varying from 5000 to 59 000 ppm. Two different types of organic extractant solutions were chosen to extract SA from aqueous streams: (a) 30% tripropylamine (TPA) dissolved in 1-octanol and (b) 30% trioctylamine (TOA)–TPA mixture in a 2:8 weight ratio and dissolved in 1-octanol. The aqueous feed was circulated through the lumens of the hollow fibres, and the extractant solution was passed through the shell side (i.e., inside the shell) of the HFMC module. Both liquids flowed counter-currently within the HFMC module and were recirculated continuously. Conditions such as SA-water flow rate, organic phase flow rate, and initial SA-water concentration were selected as the operating variables. The complexation reaction of SA with the amine was assumed at the aqueous–organic interface on the lumen side. The complex thus formed first diffused through the membrane pores filled with the organic phase (hereafter “organic-filled membrane pores”) and was subsequently swept by the organic liquid flowing through the shell side of the module. The HFMC was observed to be highly efficient in removing SA from water, and a removal efficiency of more than 95% was obtained. A mathematical analysis was performed by considering the transport of SA molecules through the bulk aqueous phase and within the organic-filled membrane pores. The results of the model simulation were shown to be in agreement with the experimental data.     

三辛胺萃取丁二酸、苹果酸、马来酸、富马酸特性的研究

Extraction equilibrium features of succinic acid, malic acid, maleic acid and fumaric acid were investigated systematically with trioctylamine (TOA) in chloroform, 4-methyl-2-pentanone (MIBK) and 1-octanol. Fourier transform-infrared (FTIR) spectroscopic analysis of organic samples loaded with the acid shows that amine forms 1:1 complex of ion-pair association with succinic acid, malic acid and maleic acid, and 1:1, 2:1 complex of ion-pair association with fumaric acid. It is proposed that the complex forms depend on the second dissociation constant of the dibasic acid, pKa2 Results of equilibrium experiments show that diluents affect extraction behavior, and depend on the solute concentration. Protic diluents, chloroform and 1-octanol, are more effective than the others when the equilibrium solute concentration is lower than 1:1 stoichiometry of TOA to acid, otherwise the extraction ability shows that MIBK>l-octanol>chloroform for malic and maleic acids, and l-octanol>MIBK>chloroform for succinic acid.     

Computational simulation on steric hindrance between hydrophobic tails of lamellar matrix composed of acyl glutamate/stearyl alcohol/behenyl alcohol by molecular dynamics

Monosodium N-stearoyl-l-glutamate (MSSG), an amino acid surfactant, could associate with higher alcohols such as stearyl alcohol (SA) and behenyl alcohol (BA) and they were self-assembled into a lamella in an aqueous phase. When MSSG, SA and BA were assumed to associate each other in molar ratios of 1:1:1, 1:2:1, 1:1:2, 1:2:2 and 1:1:3, the packing parameter of each associate was calculated using molecular dynamics (MD). Among them, only 1:1:1 associate and 1:1:3 one exhibited packing parameters of around 1. According to the result of colloidal stability, however, the lamella composed of 1:1:3 associate was poorly stable while that of 1:1:1 associate was stable. In order to explain why the colloidal stability is not related to the packing parameter, the concept of steric compressibility was introduced. Steric compressibility is a measure of vertical steric hindrance occurred between hydrophobic tails of lamella. The value of steric compressibility, calculated by MD, of 1:1:1 and 1:1:3 associates were 4.7 and 8.2, respectively. That is, the vertical repulsion in the lamella of 1:1:3 associate might be greater than in the lamella of 1:1:1 associate. This would account for why the lamella of 1:1:3 associate is poorly stable even though the packing parameter is almost 1. Besides the condition that packing parameter is to be around 1, the steric compressibility of lamella should be as low as possible to achieve a stable lamella.     

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.     

三辛胺萃取草酸的第3相特性

以三辛胺（TOA）萃取草酸时出现第3相的基本规律为研究对象,实验测定了无水溶剂及液液萃取平衡有机相中草酸的溶解度及其随TOA和正辛醇浓度的变化规律.结果显示,正辛醇对草酸及其与TOA形成的缔合物在溶剂中的溶解度影响显著;随正辛醇含量的增加,草酸及其缔合物在溶剂中的溶解度提高,因而溶剂对草酸的萃取能力随之增大;在TOA与草酸以1∶1的化学计量比饱和后,草酸溶解度出现阶跃现象,这与形成草酸二聚体的缔合物有关;相比之下,液液萃取平衡实验中有机相对草酸的溶解度大于无水溶剂的结果,溶剂中水的存在有助于缔合物溶解.同时建立了描述液液萃取平衡有机相中草酸及其缔合物溶解度的数学模型,并通过参数寻优求得了相应的模型参数.     

Equilibrium studies on reactive extraction of lactic acid with an amine extractant

Equilibrium studies on the extraction of lactic acid from aqueous solutions with tri-n-octylamine (TOA) in xylene were made in the temperature range 293–323 K. The formulation of the extracted species in the organic phase and the corresponding equilibrium constants were numerically determined at different temperatures. Also, the apparent thermodynamic functions were calculated. Finally, the effect of a water-insoluble organic acid, di(2-ethylhexyl)phosphoric acid (D2EHPA), on this extraction was investigated. Synergistic and antagonistic effects were observed in the presence of D2EHPA, mainly depending on the concentration ratio of D2EHPA to TOA.