Octanol Solvents Research Articles

DFT assessment of the alizarin dye pollutant adsorption by a customized graphene adsorbent

The alizarin (ALZ) dye pollutant adsorption by a customized zinc-atom decorated graphene (ZGR) adsorbent was assessed by density functional theory (DFT) computations. The interactions between ALZ and ZGR were explored to approach an adsorption process, in which different configurations of ALZ@ZGR complexes; A1, A2, and A3, were found. A dominant O…Zn interaction was found for all complexes in addition to the complementary C…C interaction between two substances. Accordingly, different strengths of adsorptions were determined to be meaningful for the removal purpose of ALZ by the ZGR adsorbent. The electronic molecular orbital features were also extracted to approach a sensing function of r ALZ@ZGR complexes formations, in which the variations of such features were mainly monitored by the changes of energy gap and work function. As a consequence, a platform for sensing and removal of the ALZ dye pollutant was proposed in the water and octanol solvents.

Phase behavior and intermolecular interaction analysis of the ternary system of water + 2-methylpyridine + octanols from 303.2 K to 323.2 K

Wastewater from coking and pharmaceutical processes often contain a significant amount of 2-methylpyridine, which forms an azeotropic mixture with water. Effectively and cleanly separating 2-methylpyridine from wastewater while conserving energy and obtaining high purity products is an urgent challenge. In this study, ternary liquid-liquid equilibrium (LLE) data for the extraction of 2-methylpyridine from wastewater were measured using three distinct solvents at temperatures of 303.2 K, 313.2 K, and 323.2 K. The obtained ternary data were subsequently correlated with thermodynamic models (NRTL and UNIQUAC) to get relevant binary interaction parameters, bridging a gap in Aspen Plus simulations of 2-methylpyridine separation by octanol solvents. Furthermore, the GUI tool was used to validate these parameters and the results confirmed the reliability of the obtained parameters. It was observed that as the temperature increased, the extraction performance of all systems decreased, indicating that elevated temperature are not conducive to the extraction process. Among the various components, iso-octanol showed the highest separation factor indicating better extraction efficiency of 2-methylpyridine. Additionally, this study integrated quantum chemical calculations to reveal the interaction mechanisms between different solvents, 2-methylpyridine, and water at the microscopic level. The computational results indicated that iso-octanol exhibited the most robust binding affinity with 2-methylpyridine, suggesting that iso-octanol has more excellent extraction properties.

Effect of ion to ligand ratio on the aqueous to organic relative solubility of a lanthanide-ligand complex.

In the solvent extraction of rare earth elements, mechanistic aspects remain unclear regarding where and how extractant molecules coordinate metal ions and transport them from the aqueous phase into the organic phase. Molecular dynamics simulations were used to examine how unprotonated di(2-ethylhexyl)phosphoric acid (DEHP-) ligands that coordinate the Gd3+ ion can transfer the ion across the water-organic interface. Using the umbrella sampling technique, potential of mean force profiles were constructed to quantify the relative solubility of the Gd3+ ion coordinated to 0-3 DEHP- ligands in either water, 1-octanol, or hexane solvents and at the water-organic interfaces. The simulations show the Gd-DEHP- complexes, at varying Ln-ligand ratios, preferentially solvate on water-organic interfaces. While the Gd(DEHP-)3 complex will diffuse past the aqueous-organic interface into the octanol solvent, it is thermodynamically preferred for the Gd(DEHP-)3 complex to remain in the water-hexane interface when there is no amphiphilic layer of excess ligand.

Ultrasonic-Assisted Upgrading of the Heavy Bio-Oil Obtained from Pyrolysis of Pine Nut Shells with Methanol and Octanol Solvents

Bio-oil from biomass is considered a promising fuel candidate due to its high energy density. The organic molecules in bio-oil (heavy bio-oil) that are highly viscous and corrosive are the main obs...

Rotational Diffusion of Medium Sized 7-[Diethylamino]-2H-1-Benzopyran-2-One Molecule in Alcohols: Study of Temperature and Solvent Viscosity Effect.

The rotational re-orientations times of the 7-[diethylamino]-2H-1-benzopyran-2-one (7-DHB) dye molecule have been examined in ethanol and octanol solvents when macroscopic solvent viscosity parameter is varied by varying the temperature, by employing the steady-state fluorescence depolarisation and Time-Correlated Single Photon Counting (TCSPC) techniques. Experimental observation shows that 7-DHB probe is experiencing higher friction in octanol compared to ethanol and rotates slower by a factor of 7.3. The hydrodynamic Stokes Einstein's Debye theory (SED) with a stick, slip boundary conditions parameters, quasi-hydrodynamic models (Dote-Kivelson-Schwartz and Geirer-Wirtz) were used to determine mechanical friction and found an interesting towards super slip trend. Dielectric frictional theories of point dipole, Nee-Zwanzig and van der Zwan-Hynes both models fail to describe experimentally observe dielectric friction trends. Evidently, both hydrodynamic and dielectric models failed to explain the examined behavior, even in the qualitative way in alcohols.

Fluorescence relaxation dynamics in excited electronic states of -(1,3-benzothiazol-2-yl)-7-(diethylamino) chromen-2-one (3-BDC) in alcohols

The rotational re-orientations times of the 3-(1,3-benzothiazol-2-yl)-7-(diethylamino) chromen-2-one (3-BDC) dye molecule have been examined in ethanol and octanol solvents when macroscopic solvent viscosity parameter is varied by varying the temperature, by employing the steady-state fluorescence depolarisation and Time-Correlated Single Photon Counting (TCSPC) techniques. Experimental observation shows that 3-BDC probe is experiencing higher friction in octanol compared to ethanol and rotates slower by a factor of range 3.5–5.93. The hydrodynamic Stokes Einstein's Debye theory (SED) with a stick, slip boundary conditions parameters, Quasi-hydrodynamic models (Dote-Kivelson-Schwartz and Geirer-Wirtz) were used to determine mechanical friction and found an interesting towards super slip trend. The Dielectric frictional theories of point dipole, Nee-Zwanzig and van der Zwan-Hynes both models fail to describe experimentally observe dielectric friction trends. Evidently, both hydrodynamic and dielectric models failed to explain the examined behavior, even in the qualitative way in alcohols.

Synthesis and photophysics of a series of lipophilic phosphazene‐based fluorescent indicators

AbstractThis work explores the 7‐amino‐4‐(trifluoromethyl)coumarin backbone for designing lipophilic fluorescent pH indicators. Four novel fluorescent phosphazene bases with an advantageous combination of properties—high lipophilicity of both neutral and charged forms, lack of localized charges in the cations, and prominent spectral changes upon protonation/deprotonation—were synthesized using the Staudinger reaction. The molecular structures of the synthesized compounds were confirmed using attenuated total reflectance Fourier‐transform infrared spectroscopy (ATR‐FT‐IR), nuclear magnetic resonance (NMR), and Fourier‐transform ion‐cyclotron resonance (FT‐ICR) high‐resolution mass spectrometry. The compounds were further characterized by ultraviolet‐visible (UV‐Vis) absorption and fluorescence emission spectra, lipophilicities (logP values) and pKa values in water and acetonitrile, as well as “biphasic” pKa values in the water/1‐octanol solvent system. The bases could potentially be useful as working agents in optical pH sensors and acid‐base indicators for lipophilic membranes.

Molecular dynamics simulations on the heterocyclic cyclodecapeptide and its linear analogous in water and octanol solvents

Abstract In this study, the behavior of the heterocyclic cyclodecapeptide (HCD), composed of nine glycine amino acids and one threonine, was studied by the molecular dynamics simulations. For this purpose, the linear analogous of HCD was designed in silico and the molecular simulation study for the linear and cyclic peptides was performed in the solvents of water and octanol. The diffusion constant, radial distribution function and hydrophobic accessible surface, root-mean-square deviation (RMSD) and root mean square fluctuation (RMSF) were evaluated in order to compare the behavior of linear and cyclic peptides. The values of the diffusion coefficients for the linear and cyclic forms were found to be 0.616 and 0.215 cm 2 /S in water; 0.175 and 0.148 cm 2 /S in octanol, respectively. The results show that the diffusion coefficients in water solvent for both the linear and cyclic forms of peptides are higher than those in octanol solvent. Also, the diffusion coefficients for the linear form, in both solvents, are higher than those in the cyclic form. Based on the analysis of the solvent accessible surface, the hydrophobic accessible surface areas for the linear and cyclic forms of peptides are 4.38 and 4.17 in water; 3.93 and 4.03 in octanol, respectively. The RDF results showed that the strength of O H hydrogen bonds for both linear and cyclic peptides in water is greater than N H hydrogen bonds. However, the strength of each kind of hydrogen bonds in the cyclic peptide is stronger than that of the linear peptide in water solvent. The interactions between the peptide and octanol solvent were found to be weak.

Extraction enhancement of zinc(II) in ammoniacal media through solvent and synergistic effects: A structural and mechanistic investigation

Solvent and synergistic effects on the zinc extraction in ammoniacal media have been investigated where 4-ethyl-1-phenyl-1,3-octadione is used as extractant. The structure of the extracted zinc complexes has been determined by use of FT-IR spectroscopy and X-ray absorption spectroscopy. And the interactions of the extracted species with water, ammonia and ligand molecules in the organic phase have been studied to elucidate the extraction mechanism. The extraction efficiency of zinc at pH 7.3 is more than 90% for octanol solvent system and for both trioctylphosphine oxide (TOPO) and tributyl phosphine (TBuP) synergistic systems, indicating that the polar solvent and neutral ligands containing phosphine can evidently enhance the extraction efficiency of Zn(II) in ammoniacal media. The solvent effect should be mainly attributed to the stabilization of hydrated and ammonia-solvated zinc complexes in polar solvent by intermolecular hydrogen bonding, whereas the synergistic effect could result from the formation of more hydrophobic and stable zinc adducts, which promote the distribution of zinc extracts.

Separation of niobium and tantalum from Mozambican tantalite by ammonium bifluoride digestion and octanol solvent extraction

Tantalite ore from Mozambique was digested using molten ammonium bifluoride (NH4HF2) as an alternative to hydrofluoric acid. Niobium and tantalum were extracted from the water-leached filtrate using 1- and 2-octanol as extractants. The main process variables are time, temperature and the bifluoride-to-ore mass ratio, for the bifluoride treatment step, along with the sulphuric acid concentration of the aqueous filtrate, and the solvent-extraction contact time. The optimum parameters obtained for the bifluoride treatment were a reaction time of 3h, a reaction temperature of 250°C, and a tantalite-to-bifluoride mass ratio of 1:30. Under these conditions, up to 97.24% of Nb and 98.66% of Ta were recovered. Introduction of sulphuric acid (H2SO4) into the aqueous phase increases the extraction of Nb and Ta with octanol. It is shown that a 5M to 6M sulphuric acid concentration results in good extraction of tantalum. An acid concentration higher than 5M must be used for efficient extraction of niobium. A contact time of 10min between the feed solution and the solvent is required. McCabe–Thiele equilibrium diagrams constructed from the experimental data suggest that two and three extraction stages are sufficient for almost complete extraction of Ta and Nb respectively, at optimum extraction conditions.

Water content of natural cyclodextrins and their essential oil complexes: A comparative study between Karl Fischer titration and thermal methods

The paper presents a comparative study regarding the water determination in natural cyclodextrins and in their essential oil complexes (Apiaceae, Liliaceae, and Cupressaceae families) by using Karl Fischer titration (KFT) and thermal methods. For the natural cyclodextrins, the influence of the solvent hydrophobicity and the preheating temperature on the water extraction process were evaluated. The water contents, estimated by KFT in both methanol and methanol–octanol solvent systems, were 10.6% and 14.4% for α- and β-cyclodextrin, respectively; the water content, estimated by KFT in a more hydrophilic solvent system, methanol–formamide, was 0.4–0.6% higher. Thermogravimetric evaluation of water conducts to lower values. For the essential oil/cyclodextrin complexes, the KFT water content were in the range of 6.4–8.1%, higher values being obtained in the case of Juniperus essential oil/β-cyclodextrin complexes (7.5–8.1%). With some exceptions, thermal analyses of complexes are in good agreement with the KFT results.

C60 in Model Biological Systems. A Visible-UV Absorption Study of Solvent-Dependent Parameters and Solute Aggregation

A study was made of the solubilization of C[sub 60] in various solvents and systems of biological interest, i.e., octanols, micelles, and liposomes, using visible-UV absorption spectroscopy as a diagnostic tool. The state of incorporation of C[sub 60] molecules in micellar and colloidal liposome solutions was monitored using a number of spectroscopic criteria of solute-solvent and solute-solute interactions based on comparison with spectra obtained in alkane and octanol solvents and from thin films of C[sub 60]. Spectral red shifts and intensity modifications of C[sub 60] absorption and C[sub 60] aggregation are discussed in terms of environment-dependent physical parameters. The results indicate that C[sub 60] can be dispersed in micellar solutions of Triton X-100 and Triton X-100 R-S, the fullerene molecules being localized in the inner hydrophobic part of the micelles. C[sub 60] was shown to be incorporated, mainly as aggregates, into phosphatidylcholine liposome colloidal solutions. It is concluded that micellar and liposome solutions can be prepared which could be used to transfer individual C[sub 60] molecules, or groups of molecules, to biological cells. 38 refs., 9 figs., 2 tabs.

Structural and dipolar properties of the voltage-dependent pore former alamethicin in octanol/dioxane

Dielectric constant and loss of the membrane-active peptide alamethicin in octanol/dioxane mixtures have been measured at frequencies between 5 kHz and 50 MHz. On the basis of a rotational mechanism of dipolar orientation, the observed dispersion provides information regarding size, shape, and dipole moment of the structural entities which the solute may assume in media of diverse lipophilicity. Particularly detailed results are obtained in a pure octanol solvent where an apparent molecular weight of alamethicin could be determined. It turns out that in this quite lipophilic medium most of the peptide material exists as a monomer particle that has approximate length and diameter of 35 and 13 A, respectively. It carries a dipole moment of approximately 75 Debye units (directed nearly parallel to the long axis). At our concentrations of a few milligrams per milliliters, appreciable formation of dimers by head-to-tail linkage is indicated. When the octanol content is reduced by adding greater amounts of dioxane, larger particles are encountered. This is accompanied by a decrease of the effective polarity. The inherent increase of hydrophilicity in the dioxane-enriched solvent apparently favors another monomer conformation that has a low dipole moment and easily aggregates to some kind of micelle.

Dielectric probe of the electric-field-sensitive peptide alamethicin.

Dielectric constant and loss of alamethicin in solvents of various degrees of lipophilicity (namely mixtures of n-octanol and dioxane) have been measured at frequencies from 5 kHz to 50 MHz. By means of a conventional Cole-Cole approach, dielectric properties were evaluated to obtain information about the structural and dipolar properties of the peptide in view of its function as a voltage-dependent pore former in membranes. The results for a pure octanol solvent (together with an apparent molecular weight determined by ultracentrifugation) indicate the existence of primarily monomeric particles of quite elongated shape and of comparatively high dipole moment. Adding dioxane was found to yield considerable aggregation and a decrease of polarity.