Trioctylphosphine Oxide Research Articles

Determination of a series of nonsteroidal anti-inflammatory drugs using the sensitized luminescence of lanthanides

The spectral-luminescent characteristics of a series of nonsteroidal anti-inflammatory drugs (NSAID) and their complexes with Eu(III) and Tb(III) have been studied. A possibility of NSAID determination using the sensitized luminescence of lanthanides has been shown. A synergistic effect of the impact of trioctylphosphine oxide (TOPO) and Triton X-100 on the luminescence intensity of mixed-ligand complexes La(III)-NSAID-TOPO in a micellar medium (Triton X-100), used as analytical forms, has been found. The limits of detection for NSAID in various dosage forms are from 0.012 to 2.0 μg/mL.

Quantum Dot Light-Emitting Diodes for Uniform Eight-Segment Displays

Experimental Chemicals.— Cadmium oxide (CdO, 99.998%), selenium (Se, 99.999%), 1-octadecene (ODE, 90%), oleic acid (OA, 90%), sodium hydroxide (NaOH, 98%), zinc acetate (Zn(CH3COO)2, 99.98%) and octadecylamine (ODA, 98%) were purchased from Alfa Aesar. Trioctylphosphine oxide (TOPO, 90%), hexadecylamine (HDA, 90%) and trioctylphosphorus (TOP, 97%) were purchased from SigmaAldrich. Zinc oxide (ZnO, 99.99%) and sulfur (S, 99.99%) were purchased from Aladdin. All organic solvents were purchased from Sigma-Aldrich. The chemicals were used directly without further treatment.

Tuning electronic states of a CdSe/ZnS quantum dot by only one functional dye molecule.

Self-assembly of only one functionalized porphyrin dye molecule with one CdSe/ZnS quantum dot (QD) not only modifies the photoluminescence (PL) intensity but also creates a few energetically clearly distinguishable electronic states, opening additional effective relaxation pathways. The related energy modifications are in the range of 10-30 meV and show a pronounced sensitivity to the specific nature of the respective dye. We assign the emerging energies to surface states. Time-resolved PL spectroscopy in combination with spectral deconvolution reveals that surface properties of QDs are a complex interplay of the nature of the dye molecule and the topography of the ligand layer across a temperature range from 77 to 290 K. This includes a kind of phase transition of trioctylphosphine oxide ligands, switching the nature of surface states observed below and above the phase transition temperature. Most importantly, our findings can be closely related to recent calculations of ligand-induced modifications of surface states of QDs. The identification of the optical properties emerged from a combination of spectroscopy on single QDs and QDs in an ensemble.

Jet fuel containing ligand-protecting energetic nanoparticles: A case study of boron in JP-10

Energetic particles have been used in solid propellant to increase the energy content, but for liquid fuel, the addition of such particles is still challenging because of severe particle precipitation. Here we demonstrate the possibility of adding surface-modified boron nanoparticles (NPs) in jet fuel JP-10. Trioctylphosphine oxide is very effective to stabilize NPs by inhibiting the contact and agglomeration. After 6 weeks, 12.7wt% NPs are still dispersed in fuel, which increases the density and volumetric energy from 0.93g/mL and 39.4MJ/L to 0.98g/mL and 43.4MJ/L, respectively. The suspension flows freely like liquid fuel and has relatively low viscosity at low temperature.

Structure determination and modeling of monoclinic trioctylphosphine oxide.

Trioctylphosphine oxide (TOPO), C(24)H(51)OP, was recrystallized from ambient evaporation in acetone. TOPO single crystals form with a monoclinic P2(1)/c structure. Fourier transform IR (FT-IR) spectroscopy captures the characteristic stretching modes from the seven methylene groups, the phosphoryl P=O bond, and the phosphoryl-carbon bond.

Efficacy of extraction of U(VI) by liquid emulsion membrane (LEM) using TOPO, D2EHPA and TOA

The response surface methodology is used to obtain optimal rate and extent of extraction of low concentration U(VI) (≤100 mg/L) by liquid emulsion membrane technique. Three different ligands viz. Tri-n-octyl phosphine oxide (TOPO), Tri-n-octyl amine (TOA) and Di-(2-ethylhexyl)phosphoric acid (D2EHPA), are used. 23 factorial design is applied to generate second order regression equation for studying the effect of concentration of ligand, surfactant and feed acidity. The regression model is in good agreement with the experimental data for all ligands. The rate of extraction of U(VI) by LEM is found to be in the order TOA > TOPO > D2EHPA.

Solvent extraction and stripping of lithium ion from aqueous solution and its application to seawater

For the development of lithium ion recovery process from seawater, a series of experimental researches were performed. Solvent extraction of lithium ion from aqueous solution using kerosene as solvent was proposed. Lithium ion is effectively extracted by thenoyltrifluoroacetone–trioctylphosphine oxide (TTA–TOPO) in kerosene within 80 min. Extraction efficiency is severely influenced by stoichiometric parameters. Among the stoichiometric parameters, volume ratio of aqueous (A) to extraction (E) solution is the most influential parameter. After extraction, lithium ion could be easily stripped from the extraction solution by acidic solutions. Stripping efficiency decreases with pH of acidic solutions, and the kind of acid does not affect the stripping efficiency. Extraction efficiency maintains at more than 93 % even when the extraction solution is recycled three times. 65 % of lithium ion can be extracted from seawater by this solvent extraction process when magnesium ion is precipitated by NH4OH prior to solvent extraction process. Other metallic ions in seawater decrease the extraction efficiency of lithium ion.

Green liquor extraction of hemicellulosic fractions and subsequent organic acid recovery from the extracts using liquid–liquid extraction

Extractions of hard- and softwood chips were carried out using green liquor with varying alkali charges (1%, 3%, and 5% on dry wood weight). The pulp yield of a mill was sustained while producing a by-product stream of extracted hemicellulose. The extractions were performed at 180°C for 18min and the pre-pulping extracts contained mostly xmg (=xylose+mannose+galactose), acetic acid, and formic acid. We investigated the use of a liquid extractive agent in removing fermentation inhibitors. The extraction potential of each solvent was examined at an organic to aqueous phase ratio of 1:1. The liquid–liquid extractions were performed at different temperatures (25–65°C) and pH values (0.5–3.5) for 36min. The extraction potentials of trioctylphosphine oxide (TOPO) and trialkylphosphine oxide (TAPO) were compared to determine their application in industrial-scale extraction. It was determined that the acetic acid extraction efficiency of TAPO was higher than that of TOPO. The maximum acetic acid extraction yields for the extracts derived from hard- and softwood were 83.1% and 82.1%, respectively, using TAPO as an extractant at 25°C and pH 0.5.

The Effect of Ligands on CdSe Nanoparticle Films Deposited by EPD

Nanoparticle from group II-IV semiconductor nanoparticles is widely studied for solar cells. The ability to modify the surface of nanoparticle is significant to successful use in various applications. In this research, mercaptoundecionic acid (MUA) and trioctyl phosphine oxide (TOPO) were used as ligand for cadmium selenide (CdSe) nanoparticles. The wavelength shift to a shorter value observed due to decreasing size of CdSe nanoparticle after ligand exchange from TOPO to MUA. The electrophoretic deposition methods (EPD) have being employed to deposite CdSe nanoparticles films on fluorine doped tin oxide (FTO). The deposition voltages used are between 100 - 400 V for 15 minutes. From SEM results show the formation layer of CdSe nanoparticles capped with MUA is strong and porous as compared to CdSe nanoparticle capped with TOPO. MUA capped CdSe shows better cell efficiency compared to TOPO capped CdSe which is 0.1735 %.

Synthesis, characterization, and electrical property of CdTe/trioctylphosphine oxide core/shell nanowires

Thick trioctylphosphine oxide (TOPO) layers were controllably coated onto CdTe nanowires. The shell thicknesses were readily tuned by controlling the reaction temperatures in coordinating TOPO solvent or by varying amounts of TOPO in noncoordinating ODE solvent. The shells were coherent and rough if synthesized in the TOPO solvent, while the shells became very uniform and smooth if synthesized in the ODE solvent. The electrically insulating effects of TOPO shells were directly confirmed through nanodevice of individual core/shell nanowire (NW). The present scheme to overcoat TOPO around semiconductor NWs could, in principle, be exploited to be a general approach to encapsulate a variety of colloidal nanocrystals to form novel core–shell nanohybrids.

ChemInform Abstract: Nano‐Sized Quaternary CuGa2In3S8 as an Efficient Photocatalyst for Solar Hydrogen Production.

AbstractQuaternary CuGa2In3S8 photocatalysts with a primary particle size of 4 nm are prepared by using a solution of Cu(acac)2, Ga(acac)3, In(acac)3, trioctylphosphine oxide, and oleylamine to which 1‐dodecanethiol is injected under Ar atmosphere (150 °C, aging at 285 °C for 2—24 h).

Redox Processes in the Organic Phase during Cobalt Extraction with the bis(2,4,4-trimethylpentyl)dithiophosphinic Acid and Trioctyl Phosphine Oxide Mixtures

The redox processes taking place in the organic phase during cobalt extraction with the mixtures of bis(2,4,4-trimethylpentyl)dithiophosphinic acid (HR, CYANEX 301) and trioctyl phosphine oxide (TOPO, CYANEX 921) have been studied. It was shown that CoR2 stabilization by the phosphine oxide prevents cobalt oxidation with air oxygen as well as with the disulfide of bis(2,4,4-trimethylpentyl)dithiophosphinic acid (R–R). The introduction of TOPO into the extract containing Co(III) dithiophosphinate results in an increase in the rate of cobalt reduction to Co(II). Analysis of the interphase cobalt distribution as well as of the IR and electronic absorption spectra of the extracts showed that cobalt forms a pentacoordinated tetragonal-pyramidal high-spin complex with the dithiophosphinate ions and TOPO with a tetragonal-pyramidal geometry. The base of the pyramid is made up of sulfur atoms while an oxygen atom is on the top. The composition of the complex was found to be CoR2·TOPO. Examples of the possible use of the CYANEX 301 and trialkyl phosphine oxide (TAPO, CYANEX 923) mixtures in cobalt extraction technology are given.

Effective supported liquid membranes for facilitated extraction phenomenon of cadmium (ii) ions from acidic environments: Parameters and mechanism

We have developed three new supported liquid membranes (SLMs), for removal of Cd(II) from acidic environments. For the preparation of adopted membranes, we used a plate paper of the polymer PVDF, as porous support with thickness of 100 μm and pore diameter of 0.45 μm, and respectively, amphiphilic molecules of methyl cholate (MC), Trioctylphosphine oxide (TOPO) or tri‐n‐octylamine (TOA) as extractive agents, each dissolved in the organic phase toluene. We have developed a kinetic model to calculate the macroscopic parameters, permeability (P) and initial flux (J0) on the adopted membrane, and a thermodynamic model to determine the microscopic parameters, association constants (Kass) and apparent diffusion coefficients (D*), specific to the association of the substrate with the extractive agent, and diffusion of formed complex (TS) through the membrane organic phase. The proposed models verify the experimental results. We observed the influence of the agent nature, its concentration and the substrate concentration, on the parameters for the facilitated extraction of these ions through each of the developed membranes. On the other hand, these results show that the migration of Cd(II) through the membrane, is not a simple diffusion movement, but this migration is done according to the substrate successive jumps from one site to the other of extractive agent. In order to understand this mechanism and explain the obtained results, we have studied temperature factor influence, and we have calculated the activation parameters (Ea, ΔH≠, Δ S≠) related to the transition state for the association reaction of substrate with MC and TOA agents.

Removal of chromium(III) from aqueous solutions using an advanced extraction technique (AET)

The removal of chromium(III) from aqueous solution using an advanced extraction technique (AET) such as emulsion liquid membrane (ELM) was investigated. Tri-butyl phosphate (TBP) and tri-n-octylphosphine oxide (TOPO) as carriers, commercial kerosene as an organic solvent, sorbitan monooleate (Span 80) as hydrophobic surfactant agent, sodium hydroxide, and sulfuric acid or ammonium persulfate as a stripping phase were used. The influence of the carrier concentration (5–30% w/w), surfactant (2–8% w/w), and external phase (5–50 mg/L), contact time, internal phase type (H2SO4, (NH4)S2O8 or NaOH), stirring speed (100–1200 rpm), W/O emulsion/external aqueous phase volume ratio (0.05–1) and the diluent type (hexane, heptane, and kerosene) on the extraction process was investigated. The obtained results showed that, at the optimum condition, practically all the chromium(III) ions were removed from the feed solution during the first 25 min of operational time. The best TBP/TOPO ratio in the organic phase that conducted to very good removal efficiency (≥99%) and excellent emulsion stability was 90/10% (w/w). The use of ultrasound irradiations in the emulsification step enhanced the emulsion stability. The US-ELM process appears to be a suitable alternative to develop a method for heavy metal ions removal from aqueous solution, and has been identified to give highest heavy metals recovery.

TOPO-capped silver selenide nanoparticles and their incorporation into polymer nanofibers using electrospinning technique

Electrospinning is the most common technique for fabricating polymer fibers as well as nanoparticles embedded polymer fibers. Silver selenide nanoparticles were synthesized using tri-n-octylphosphine (TOP) as solvent and tri-n-octylphosphine oxide (TOPO) as capping environment. Silver selenide was prepared by reacting silver nitrate and selenium with tri-n-octylphosphine (TOP) to form TOP–Ag and TOP–Se solutions. Both absorption and emission spectra signify the formation of nanoparticles as well as the TEM which revealed spherical particles with an average particle size of 22nm. The polymer, PVP used was prepared at concentrations ranging from (35 to 45wt%) and the TOPO-capped silver selenide nanoparticles (0.2 and 0.6wt%) were incorporated into them and electrospun by varying the voltage from 11 to 20kV. The SEM images of the Ag2Se/PVP composite fibers revealed the fibers of diameters with average values of 425 and 461nm. The X-ray diffraction results show peaks which were identified due to α-Ag2Se body centered cubic compound. The sharp peak observed for all the samples at 2θ=44.5 suggest the presence of Ag in the face centered cubic which can be attributed to higher concentration of silver nitrate used with molar ratio of selenium to silver and the abundance of silver in the silver selenide crystal. Fourier transform infrared spectroscopy, thermogravimetric analysis (TGA) and ultraviolet–visible spectroscopy were used to characterize the structure of the PVP/Ag2Se composite fibers.

Removal of Chromium(VI) from Industrial Effluents Through Supported Liquid Membrane Using Trioctylphosphine Oxide as a Carrier

The present study describes extraction of chromium(VI) through supported liquid membrane (SLM), Celgard 2400, which was impregnated with trioctylphosphine oxide (TOPO) dissolved in toluene. The stripping phase was comprised of diphenylcarbazide (DPC) in sulfuric acid (H2SO4) whereas the feed phase consists of potassium dichromate (K2Cr2O7) and hydrogen peroxide (H2O2). The effects of concentrations of chromium, TOPO, DPC, and H2SO4 have been studied in order to evaluate the transport efficiency of chromium(VI) ion. The optimum experimental conditions for the chromium(VI) extraction were established as follows: 19.2 × 10−4 mol L-1 chromium ion, 1.5 mol L-1 H2O2 concentration in the feed phase, 0.1 mol L-1 TOPO concentration in the membrane phase and 0.001 mol L-1 DPC and 1.5 mol L-1 H2SO4 as stripping phase. The measurements of percent recovery, distribution coefficient, flux and permeability were made at the given optimized conditions. The extraction time and membrane stability were also investigated. Extraction efficiency of 80% was recorded in 180 min and the SLM system was found stable up to 10 days. The optimized SLM system was then applied on the paint industry wastewater; about 80% of chromium(VI) was successfully removed from the wastewater.

Synthesis, Structural and Optical Properties of TOPO and HDA Capped Cadmium Sulphide Nanocrystals, and the Effect of Capping Ligand Concentration

The thermal decomposition of bis(N,N‐diallyldithiocarbamato)Cd(II) in a “one‐pot” synthesis in tri‐n‐octylphosphine oxide (TOPO) and hexadecylamine (HDA) afforded CdS (TOPO‐CdS and HDA‐CdS) of varying optical properties and morphologies. The influence of the ratio of the precursor concentration to the capping molecule, as a factor affecting the morphology and size of the nanoparticles, was investigated. The particles varied in shape from spheres to rods and show quantum size effects in their optical spectra with clear differences in the photoluminescence (PL) spectra. The PL spectrum of the HDA capped CdS nanoparticles has an emission maximum centred at 468, 472, and 484 nm for the precursor to HDA concentration ratio of 1 : 10, 1 : 15, and 1 : 20, respectively, while the TOPO capped nanoparticles show emission peaks at 483, 494, and 498 nm at the same concentration ratio. Powdered X‐ray diffraction (p‐XRD) shows the nanoparticles to be hexagonal. The crystallinity of the nanoparticles was evident from high resolution transmission electron microscopy (HRTEM) which gave well‐defined images of particles with clear lattice fringes.

Stretch exponential luminescence decay of CdSe/ZnS quantum dots in colloidal solutions

The luminescence decay of CdSe/ZnS quantum dots (QDs) coated with shells of trioctylphosphine oxide (TOPO) molecules and placed in colloidal solutions has been investigated. It is shown that the experimental luminescence kinetics is well fitted by the function \(I(t) = I_0 \exp \left[ { - \frac{t} {{2\tau _1 }} - A\left( {\frac{t} {{2\tau _1 }}} \right)^\beta } \right]\), where I0 is the initial luminescence intensity, β = 0.52 ± 0.2, τ1 = 50 ns, and constant A depends on the QD size. Time τ1 = 50 ns is interpreted as the lifetime of the QD excited state. The parameter β ≈ 0.5 indicates that the excited state is quenched via dipole-dipole energy transfer from the QD to energy acceptors (TOPO molecules and/or local bonds (C-H) in the solvent).

Novel route for the synthesis of surfactant-assisted MoBi2(Se0.5Te0.5)5 thin films for solar cell applications

As-deposited thin film shows a fibrous reticulate framework, SDS-assisted synthesis produces a dendrite star fish like morphology, and TOPO-assisted synthesis produces nanothreads with flakes.

Recovering copper ions from industrial environments by supported liquid membranes: parameters and mechanism

The technique of supported liquid membranes (SLM) was used to achieve the facilitated extraction of Cu(II) ions from acidic solutions, with triocthyl amine (TOA), methyl Cholate (MC) and Tri-n-octyl phosphine oxide (TOPO) as carriers , toluene as organic phase and a flat film of polyvinylidene difluoride (PVDF) as hydrophobic support (0.45 μm pore) . The macroscopic parameters, permeability P and initial flux J 0 related to facilitated extraction of these ions have been determined, for the three carriers and different concentrations of Cu (II) ions, a net evolution of these parameters, were observed. To explain this facilitated transport and extraction phenomenon of these ions by this membrane type (SLM), a mechanism based on the complexation of Cu (II) ions by the carrier and the diffusion of the formed complex through the SLM organic phase has been developed. Experimental results verify the mechanism and allow to find the optimum carrier, and to determine the values of microscopic parameters, association constant K ass and apparent diffusion coefficient D*, relating to the migration of the complex substrate-carrier, through the membrane organic phase.