Trioctylamine Research Articles

Extraction of Gibberellic Acid from Aqueous Solution by Trioctyl Amine (TOA)

Gibberellic acid (GA) extraction from fermentation broth by trioctyl amine (TOA), which is a long chain aliphatic amine was studied. Initial concentration of GA was 0.65 g · L−1. This was performed using the fungi Gibberella fujikuroi in fermentation. Alcohols (isoamyl alcohol, n-octanol, n-decanol) have been used to dissolve TOA for preparing organic phases. All experiments were studied as batch extraction. Distribution coefficients (KD), loading factors (Z), and extraction efficiency (E) were calculated. The highest extraction efficiency, distribution coefficient, and loading factor were achived with isoamyl alcohol diluent as value of 80.6, 98.7, and 4.58, respectively. Furthermore, the linear solvation energy relationship (LSER) model including Hansen solubility parameters regressed to experimental results. The LSER model predicts a close resemblance of experimental data.

Adsorption properties and behavior of the platinum group metals onto a silica-based (Crea + TOA)/SiO2–P adsorbent from simulated high level liquid waste of PUREX reprocessing

To separate platinum group metals (PGMs) from high level liquid waste (HLLW), a novel silica-based (Crea + TOA)/SiO2–P adsorbent was synthesized by impregnating Crea (N′,N′-di-n-hexyl-thiodiglycolamide) and TOA (trioctylamine) two extractants into the macroporous SiO2–P support with a mean diameter of 60 μm. Adsorption properties and behavior of PGMs from simulated HLLW onto the novel silica-based (Crea + TOA)/SiO2–P adsorbent were investigated by batch method. It was found that (Crea + TOA)/SiO2–P adsorbent exhibited good adsorption selectivity for PGMs over the other tested fission product element in a wide HNO3 concentration. This adsorbent showed strong affinity to Pd(II) but almost no adsorption for rare earth elements. Adsorption process of PGMs could be expressed by Langmuir monomolecular layer adsorption mode and be governed by the chemisorption process. In addition, the adsorption isotherms and thermodynamic parameters of tested elements were calculated by Langmuir equation, Freundlich equation and van’t Hoff equation, respectively.

Production and separation of no-carrier-added 73 As and 75 Se from 7 Li irradiated germanium oxide target

Abstract This work reports for the first time 7Li-induced accelerator based production of 71,72,73,74As, 75,76,77Br and 73,75Se radionuclides in their no-carrier-added (nca) state. After the decay of all short-lived radionuclides 75Se and 73As were only existing radionuclides in germanium oxide target, which were subsequently separated by liquid-liquid extraction (LLX) using trioctylamine (TOA) dissolved in cyclohexane as liquid ion exchanger. The presence of stable germanium in various fractions was examined by Inductively Coupled Plasma Optical Spectrometry (ICP-OES). At 0.1 M TOA and 10 M HCl concentration, 75Se and stable Ge were extracted into the organic phase leaving 73As in the aqueous phase. The bulk Ge was stripped back to the aqueous phase by 1 M NaOH, keeping 75Se in the organic phase. Therefore complete separation between 73As, 75Se and bulk Ge was achieved.

A new method for analysis of sunset yellow in food samples based on cloud point extraction prior to spectrophotometric determination

A simple new micelle mediated preconcentration method was developed for analysis of sunset yellow (SY) prior to its spectrophotometric determination. The method was based upon cloud point extraction of the ion associate of SY and trioctylamine (TOA) in HCl–Triton X-100. In the surfactant phase the SY species react with TOA yielding hydrophobic ion associate of SY−·TOA+. The distribution coefficient of SY between surfactant-rich phase and aqueous phase was approximately 104. Validation was tested by comparing the results with standard HPLC. Isotherm and thermodynamic parameters, chemical equilibrium, extraction constants and stiochiometry of the associate were assigned.

Preparation and characterization of silicone resin nanocomposite containing CdSe/ZnS quantum dots

AbstractWe report the preparation of the core/shell cadmium selenide/Zinc sulfide quantum dots (CdSe/ZnS QDs)‐silicone resin nanocomposite through the solution‐mixing method, followed by thermal hydrosilylation. After dispersing QDs into Dow Corning two‐component silicone resins (OE6630A and OE6630B at 1:4 mixing ratio by weight), the resins were cured at 150°C for 1.5 h to produce QD‐silicone resin nanocomposites. The curing behavior of the silicone resins resulting from the thermal hydrosilylation was studied using differential scanning calorimetry (DSC). The properties of the QD‐silicone resin nanocomposites were investigated by ultraviolet–visible (UV–vis), fluorescence, confocal laser scanning microscopy (CLSM), atomic force microscopy (AFM), and thermogravimetric analysis (TGA) measurements. The QDs that contain trioctylamine (TOA) as the original ligand can poison the Pt catalyst in the resins and inhibit the curing process by increasing the exothermic peak temperature, at which a lower heat of hydrosilylation is observed. Incorporating a small amount of CdSe/ZnS QDs (0.1 wt%) can greatly improve the thermal stability of the silicone resins. Moreover, CdSe/ZnS QDs tend to form clusters that are relatively homogeneously distributed in a cured silicone resin, offering good optical properties of 11.2 lm W−1 luminous efficiency and 14.6% photoluminescence conversion efficiency (PCE) in light emitting device (LED) test. POLYM. COMPOS., 2012. © 2012 Society of Plastics Engineers

Dark-red-emitting CdTe/Cd1-xZnxS core/shell quantum dots: preparation and properties

CdTe nanocrystals (NCs) were fabricated through an organic synthesis. The growth and properties of CdTe NCs depended strongly on the preparation conditions. In a reaction system of octadecene and tetradecylphosphonic acid (TDPA), the growth was slow. CdTe NCs with cubic-like morphology were created in trioctylamine (TOA) using octadecylphosphonic acid (ODPA)-CdO or TDPA-CdO as precursors. The TOA and ODPA system gives rise to NCs with high photoluminescence (PL) efficiencies (12%). A Cdx Zn1-x S shell coating on the CdTe core, gave rise to tunable dark red PL (630-670 nm). The morphology and PL properties of the CdTe cores were drastically affected by shell coating and this determined the properties of CdTe/Cdx Zn1-x S NCs. Small CdTe NCs were easily coated with Cdx Zn1-x S shells. The resulting core/shell NCs revealed a spherical morphology. However, shell growth became slow when large CdTe cores were used. This is ascribed to the cores with a cubic-like morphology. CdS interlayer plays an important role for the formation of the CdTe/Cdx Zn1-x S NCs because the experimental result indicated it is difficult to coat CdTe NCs with a ZnS shell. The core/shell NCs benefited from a Cdx Zn1-x S composite shell because CdTe/CdS NCs created via a similar procedure revealed a low PL efficiency.

Synthesis of Fe3O4 Nanoparticles with Tunable and Uniform Size Through Simple Thermal Decomposition

A novel and facile method with low cost has been developed to fabricate Fe3O4 nanoparticles (NPs) with tunable and uniform sizes by the thermal decomposition of iron oleate complex. The synthesis of iron oleate complex was carried out using a reaction between oleic acid and FeCl3 x 6H2O at low temperature. The decomposition of iron oleate complex occurs when the complex added in the solution of octadecene (ODE) and trioctylamine (TOA) with simple heat treatment. The X-ray diffraction pattern of a resulting sample indicated that Fe3O4 NPs formed during the decomposition of iron oleate complex. Preparation conditions including reaction time and temperature, the concentration of the complex, and the ratio of TOA and ODE strikingly affected the size and size distribution of resulting Fe3O4 NPs. Under optimal preparation conditions, the size of Fe3O4 NPs was adjusted (less than 20 nm in average diameter). The analysis of samples by a Fourier transform infrared spectroscopy confirmed the formation of iron oleate complex. Because the Fe3O4 NPs revealed a superparamagnetic property as well as tunable and uniform sizes, the NPs will be utilizable for further applications. This simple strategy with low cost has to give a useful enlightenment for the design and fabrication of magnetic oxide.

Reactive Extraction of Cyclic Polyhydroxy Carboxylic Acid Using Trioctylamine (TOA) in Different Diluents

Quinic acid is a cyclic polyhydroxy carboxylic acid compound that is implicated in the perceived acidity of raw materials. It is a constituent of the tannins. In this work, the extraction of quinic acid was studied by using trioctylamine (TOA) with respect to the functional groups. The quinic acid extraction experiments employed TOA + solvent mixtures or pure solvent. The solvents included two acetates, two alcohols, and two ketones. The obtained experimental results of the extraction experiments are reported as distribution coefficients, KD, loading factors, Z, and extraction efficiencies, E. The highest synergistic extraction efficiency was found to be 83.191 % for the TOA + 1-octanol extractant system, which had a KD value of 4.949 and a Z value of 0.258.

Liquid–liquid extraction for recovery of paclitaxel from plant cell culture: Solvent evaluation and use of extractants for partitioning and selectivity

A major challenge in the production of metabolites by plant cells is the separation and purification of a desired product from a number of impurities. An important application of plant cell culture is the biosynthesis of the anticancer agent paclitaxel. Liquid-liquid extraction plays a critical role in the recovery of paclitaxel and other valuable plant-derived products from culture broth. In this study, the extraction of paclitaxel and a major unwanted by-product, cephalomannine, from plant cell culture broth into organic solvents is quantified. Potential solvent mixtures show varying affinity and selectivity for paclitaxel over cephalomannine. The partition coefficient of paclitaxel is highest in ethyl acetate and dichloromethane, with measured values of 28 and 25, respectively; however, selectivity coefficients are less than 1 for paclitaxel over cephalomannine for both solvents. Selectivity coefficient increases to 1.7 with extraction in n-hexane, but the partition coefficient decreases to 1.9. Altering the pH of the aqueous phase results in an increase in both recovery and selectivity using n-hexane but does not change the results for other solvents significantly. The addition of extractants trioctylamine (TOA) or tributylphosphate (TBP) to n-hexane gives significantly higher partition coefficients for paclitaxel (8.6 and 23.7, respectively) but no selectivity. Interestingly, when 20% hexafluorobenzene (HFB) is added to n-hexane, the partition coefficient remains approximately constant, but the selectivity coefficient for paclitaxel over cephalomannine improves to 4.5. This significant increase in selectivity early in the purification process has the potential to simplify downstream processing steps and significantly reduce overall purification costs.

Structural analysis of N[sbnd]H⋯O in viscoelastic scum formation during solvent extraction of sulfuric acid with trioctylamine

In the paper, Fourier transform infrared spectroscopy combined with Gaussian function linear fitting is used to analyze the structure of the viscoelastic scum formed during solvent extraction of sulfuric acid with trioctylamine (TOA). The results show that when the molar ratio of sulfuric acid to TOA is low in the system, it would form N⋯HO through TOA coupling with sulfuric acid or TOA coupling with water. The N⋯H stretching vibration is around 3400cm−1. With the increase of molar ratio of sulfuric acid to TOA, three peaks, near 2660cm−1, 2610cm−1, and 2535cm−1, appear in the infrared spectrum and they are assigned to NH+ combining with water, NH+ combining with OS, NH+ combining with water and OS in the extraction system. The wave-number of CN stretching vibration increases with the increase of molar ratio of sulfuric acid to TOA.

A novel approach for itaconic acid extraction: Mixture of trioctylamine and tridodecylamine in different diluents

Extraction of itaconic acid has been investigated from aqueous solutions by six kind of different solutions of trioctylamine (TOA)–tridodecylamine (TDA) mixtures. Solvents have selected as dimethyl phthalate (DMP), methyl isobutyl ketone (MIBK), 2-octanone, 1-octanol, cyclohexyleacetate (CHA), and 1-decanol. Distribution and equilibrium data for design of separation equipments have been obtained as a result of batch extraction of itaconic acid. It has been calculated that distribution coefficients (D), loading factors (Z), extraction efficiency (E). The maximum removal of itaconic acid has been obtained as 98.39% with DMP and 3.14molL−1 initial concentration of TOA–TDA mixture.

The Separation and Concentration of Titanium(IV) from Sulfuric Acid Solution with Trioctylamine

This paper presents research on separating and concentrating titanium(IV) from aqueous sulfuric acid solution, using trioctylamine (TOA) as extractant and kerosene as a diluent. We investigated the effects of reaction time, temperature, sulfuric acid concentration, organic/aqueous phase ratio, TOA concentration, and titanium concentration on the removal efficiency of titanium(IV). The results show that it is possible to recover over 99% of titanium(IV) after 15 min reaction time by TOA from the sulfuric acid solution under the optimum operation conditions and the loading capacity of TOA for titanium(IV) is 30 g Ti(IV)/100 g TOA. We expect that results studied would be applicable to separate and concentrate titanium from secondary sources such as red mud produced in the aluminum/alumina industry.

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.

Development of Adavanced Separation Technology of Rare Metals Using Extraction and Crystallization Stripping

In a present process to treat the tungsten carbide tool waste, the wastes are roasted in air and then an alkali leaching is carried out in an autoclave. An environmentally friendly process is required to recover rare metals (Co and W) from the wastes. The effect of mechano-chemical (MC) treatment on leaching of rare metals was investigated in this study. The solvent extraction and crystallization-stripping methods were applied to separate and recover tungsten and cobalt in the leached solutions.The MC treatment for the rare metal leaching is effective to dissolve rare metals from the wastes due to the change in crystalline structure of WC and oxidation of WC with KMnO4. Cobalt ions are extracted with D2EHPA by a cation exchange reaction. Tungsten in the leachate can be extracted by TOA (tri-octyl amine) as an extractant, because tungsten species exist as a form of anionic species in acidic solution. The rare metals in organic phase are recovered as insoluble salts such as oxalates and ammonium salts in the crystallization-stripping process.

Layered hybrid organic–inorganic nanobelts: synthesis and removal of trace heavy metal ions

Cobalt phosphate-based organic-inorganic hybrid nanobelts were successfully synthesized in the presence of trioctylamine (TOA) via a solvothermal system. The inorganic cobalt phosphate layers and organic n-octylamine layers in this structure arranged alternately, both of which were parallel to the axial direction of the nanobelts, and the layered distance is 4.0 nm. The formation of this nanostructure proceeds via two reactions. Trioctylamine molecules undergo C-N bond cleavage to form octylamine via the redox reaction between the Co(III) and trioctylamine. Octylamine was protonated to incorporate into the inorganic framework, resulting in the formation of organic-inorganic hybrid nanobelts. In addition, the as-synthesized nanobelts show excellent removal ability for the trace heavy metal ion Pb(2+) in wastewater.

Emulsion liquid membrane for cadmium removal: Studies on emulsion diameter and stability

This paper presents a comprehensive study on emulsion diameter and removal capacity of Cd(II) from aqueous solution using emulsion liquid membrane (ELM). The liquid membrane consists of trioctylamine (TOA) as a carrier, kerosene as an organic diluent, ammonia as a stripping solution and Span 80 (sorbitan monooleate) as an emulsifying agent, prepared using ultrasonic. The important parameters affecting the emulsion diameter for recovery of Cd(II) including emulsification time, surfactant concentration, carrier concentration, and volume ratio of membrane to internal phase were systematically studied. The effects to membrane breakage were also investigated. The effect of emulsion diameter on the removal capacity of Cd(II) was also studied as its important role in the permeation process. The results showed that the emulsion diameter ranging from 0.878 up to 2.46μm. The highest removal capacity was 0.493mg Cd/ml emulsion while the lowest membrane breakage was 0.117% were obtained at the smallest emulsion droplets diameter.

Effect of hydroxyl on formation of viscoelastic scum during solvent extraction of sulfuric acid with trioctylamine

In the paper, Fourier transform infrared spectroscopy (FTIR) is employed to investigate the formation of viscoelastic scum during solvent extraction of sulfuric acid with trioctylamine (TOA) as extractant. The spectra are deconvolved and peak-fitted to study the change of wave-number and the peak area of O–H stretching vibration. Results suggest that the water plays an important role in viscoelastic scum formation. The water, sulfuric acid and TOA can combined as SO…HOH…N or HOH…OS or NH…OS. With the increase of the molar ratio of sulfuric acid to TOA, the combination of the water, sulfuric acid and TOA would transform to SO…HOH…OS or N+…HOH, which may be form macro-molecules in the extraction system.

Effective separation of iron from titanium by transport through TOA supported liquid membrane

Separation of iron from titanium acidic solutions with tri-octylphosphine oxide (TOPO) and trioctylamine (TOA) has been investigated. TOA was found to be more selective for extraction of Fe compared with TOPO from HCl concentrations >1 M. Iron could be stripped effectively from the loaded TOA in 1 M HClO 4. Parameters affecting the transport separation of iron from titanium ions have been studied using a supported liquid membrane impregnated with TOA in kerosene. HCl and HClO 4 were used as feed and product solutions, respectively. Transport curves have been developed and Fe transport rate constant, k f, together with the time of 99.9% transport, t 99.9, have been estimated. At 1 M HCl, 25 °C and 0.46 M TOA, Fe and Ti were practically not transported. By increasing the HCl concentration, the Fe transport was greatly improved where the t 99.9 reached 96 h at 5 M HCl. The Fe transport was further improved by rising the TOA concentration to 1.15 M and the temperature to 80 °C. Under these conditions about 80% of Fe was transported after only 1.5 h and the t 99.9 reached 6.4 h without any significant co-transport of Ti ions. The transport process seemed to be controlled by diffusion in the organic phase through the membrane since increasing the temperature enhanced the Fe transport. Although, direct leaching of ilmenite in HCl is known to be very limited, transport separation of Fe from the slurry by the present TOA-membrane system has lead to superior dissolution of Fe and Ti.

The liquid–liquid equilibria for low pH aqueous acid solution + tri-octylamine (or tri-butylphosphate) + 1-decane and the binary and ternary excess molar volumes and deviations of the refractive indices

Liquid–liquid phase equilibria (LLE) for the ternary system containing water + tri-octylamine (TOA) or tri-butylphosphate (TBP) + 1-decane were reported in a previous paper. These ternary combinations can be used as selective solvents and diluents in the molybdenum (Mo) extraction process. In the interest of industrial applicability, the LLE for the system containing aqueous sulfuric acid solution (pH 1.0) + TOA or TBP + 1-decane has been discussed at the temperature of 298.15 K and a normal atmospheric pressure. The solubility of TOA and TBP in water was a little decreased with the addition of sulfuric acid. Nonrandom two-liquid (NRTL) and universal quasichemical (UNIQUAC) models were used for the description of the determined LLE data. In addition, the density ( ρ) and the refractive index ( n D) for the systems TOA + 1-decane and TBP + 1-decane at 298.15 K were determined. These data were used to calculate the binary excess molar volume ( V E) and the deviations of the refractive indices (Δ R) over the entire composition range. The ternary V E and Δ R prediction for the TOA + TBP + 1-decane system was determined from the binary data with the Radojkovič equation.

Synthesis of linear ZnO structures by a thermal decomposition method and their characterisation

The semiconductor zinc oxide (ZnO) is a promising material for applications in optoelectronics, photochemistry and chemical sensing. Furthermore, ZnO structures can be grown with a large variety of sizes and shapes. Devices with ZnO rods or wires as their core elements can be used in solar cells, gas sensors or biosensors. In this article, an easy approach for the non-aqueous wet chemical synthesis of ZnO structures is presented that employs the solvent trioctylamine (TOA) and the surfactant hexamethylenetetramine (HMTA). Using the thermal decomposition method, rod-shaped structures were grown that are suitable for the fabrication of electrical devices. A detailed study was carried out to investigate the effects of various reaction parameters on the growth process. Both the concentration of the surfactant HMTA and the zinc precursor zincacetylacetonate (Zn(acac)2) were found to show strong effects on the resulting morphology. In addition to structural characterisation using XRD, SEM and TEM, also optical properties of rod-shaped ZnO structures were measured. Rod-shaped structures were obtained for the following conditions: reaction time 4 h, reaction temperature 70 °C, 1 mmol of Zn(acac)2, 4 mmol of HMTA and 25 mL of the solvent TOA. Photoluminescence and photoluminescence excitation spectroscopy of samples grown under these conditions provided information on levels of defect states that could be critical for chemical sensing applications. Two narrow peaks around 254 and 264 nm were found that are well above the band gap of ZnO.