Hexane-water System Research Articles

Effective hydrogen generation using water-n-hexane-ZrO2 system: Effect of temperature and radiation irradiation time

There is a great demand for economic green hydrogen fuel production and, consequently, hydrogen generation by water radiolysis of a hexane-water system on ZrO2 surface is presented at various temperatures. The radiation-catalytic decomposition of the hexane-water had increased at high temperatures i.e. ranging from 300 to 673 K. It caused an increase in the yield of hydrogen production in the radiation-catalytic decomposition of hexane-water. It was observed that at a temperature of T = 673 K a chain mode of conversion of the key products of hexane-water resulted in molecular hydrogen. Finally, the maximum yield of hydrogen was 188.5 molecule/100 eV with n-ZrO2 + C6H14(ads)-water (0.003 g: 0.0051 g: 0.0015 g) at 673 K.

Direct Investigation of Synthesis of Gold Nanoparticles Using Polyscias scutellaria Leaf Extract in the Hexane-Water System Using the Centrifugal Liquid Membrane-Spectrophotometry Method

The Centrifugal liquid Membrane (CLM) method, which provides an ultra-thin two-phase liquid membrane system in a rotating glass cell, was successfully applied to Green Synthesis from Polyscias scutellaria (PS) capped gold nanoparticles (AuNPs-PS) using a Mangkokan leaf (Polyscias scutellaria) extract as a reducing agent and stabilizer in the hexane-water system. PS extract in hexane fraction as the organic phase has a UV absorption spectrum at the maximum wavelength, λmax of 220 nm, while the precursor of HAuCl4 solution as an aqueous phase has an λmax of 214 nm. Investigation of AuNPs-PS formation was carried out at various concentrations of Mangkokan leaf extract concentration; i.e., 0.001 0.003; 0.005; 0.007 and 0.009%, while the reaction was carried out at various rotational speeds of 5,000-9,000 rpm. The formation and stability of AuNPs-PS were observed from the phenomenon of surface plasmon resonance (SPR) and absorbance changes as measured by a UV-Vis spectrophotometer. The results of measurements using CLM-Spectrophotometry shows the formation of AuNPs-PS in the hexane-water system at λmax of 534 nm.

Fabrication of Gd2O3 nanoparticles in hexane-water system using Myristica fragrans Houtt leaves extract and their photodegradation activity of malachite green

This study aims to fabricate the Gd2O3 nanoparticles (NPs) using Myristica fragrans Houtt leaves extract (MFE) in hexane-water phases system by high-speed stirring method. We performed a phytochemical test to qualitatively confirm that MFE contained the secondary metabolite of alkaloid, steroid and saponin as a weak base source (OH−), a stabilizing agent, and a capping agent in the Gd2O3 NPs fabrication, respectively. According to SEM image, the morphology of Gd2O3 NPs was spherical shape in agglomeration. UV-Vis DRS result shows that Gd2O3 NPs has a large bandgap which was found to be 5.1 eV. XRD characterization shows that the diffraction pattern of the formed nanoparticle was well-matched with the data source of Gd2O3. The particle size of Gd2O3 NPs was approximately 40 nm confirmed by PSA. Photocatalytic activity of Gd2O3 NPs was tested for dye degradation. In this study, malachite green was utilized as a modelling of dye. The photodegradation percentage of malachite green using Gd2O3 NPs catalyst was 75.15 % for 120 min under UV light irradiation.

Determination of pyrolytic water composition forming during thermal processing of automobile tyres

The study of the chemical composition of water formed during pyrolysis of waste tyres was made. The obtained pyrolytic water was characterized by FT-IR techniques, gas chromatography-mass spectrometry, dissociation extraction and a distribution chromatography method. It was found out that pyrolytic water consists of about 93 compounds, from which 27 compounds were identified by GC-MS method. Quantitative analysis established that total content of compounds is up 0,90 g/dm3, from which caprolactam – 46 %, cyclohexanone – 5, aniline – 17, benzonitrile – 6, о-cresol – 2,6, p-cresol – 2,8, benzothyazole – 4,9, 2,4-dimethylquinoline – 4,6, phthalimide – 2,5 %. By dissociative extraction of organic acids and bases it was shown that peaks of some components of chromatogram contain minor components. Distribution coefficients in hexane-water system of cyclohexanone, aniline, benzonitrile, о-cresol, p-cresol, 2,5-dimethylphenol, benzoic acid, benzothyazole, caprolactam, 1-methyl-isoquinoline, 2,4-dimethylquinoline and phthalimide were defined.

Substantiation of the Selection of Trifluoroacetophenone Derivatives for the Manufacture of Membranes of Sulfate- and Carbonate-Selective Electrodes

The distribution of trifluoroacetophenone (TFAP) and its derivatives—p-methyl trifluoroacetophenone (p-MTFAP), 2,4-dimethyl trifluoroacetophenone (DMTFAP), 2,4,6-trimethyl trifluoroacetophenone (TMTFAP), and heptyl p-trifluoroacetylbenzoate (H-p-TFAB)—in a hexane–water system, which simplifies a polyvinylchloride membrane of selective electrodes, is studied by UV spectrophotometry and chromatography. These substances are used as neutral carriers (NCs) in membranes of ion-selective electrodes reversible to doubly charged carbonate and sulfate ions. The hydration of TFAP and some of its derivatives is systematically investigated. It is found that TFAP has higher solubility in water (partition coefficient D = 415) compared to those of p-MTFAP, DMTFAP, TMTFAP, and H-p-TFAB (D = 1360–2700), which makes it unsuitable as a neutral carrier for manufacturing membrane electrodes. H-p-TFAB is most strongly hydrated in an alkaline medium. It is found that p-MTFAP and H-p-TFAB form crystalline hydrates. The selectivity coefficients for the carbonate- and sulfate-selective electrodes are determined for all the neutral carriers studied; the selectivity of the electrodes increases in the series TFAP < p-MTFAP < DMTFAP < TMTFAP < p-BTFAP (p-butyl trifluoroacetophenone) < H-p-TFAB.

Investigation of hydration and distribution of trifluoroacetophenone and its derivatives in hexane – aqua system

UV spectrophotometric and chromatographic study of the distribution and hydration of trifluoroacetophenone (TFAF) and some its derivatives ( p-trifluoroacetyl benzoic acid heptyl ester (TFABAHE), p-methyltrifluoroacetophenone ( p-MTFAF), 2,4-dimethyltrifluoroacetophenone (DMTFAF), 2,4,6-trimethyltrifluoroacetophenone (TMTFAF)) in the hexane-water system, which models the polyvinyl chloride membrane of ion-selective electrodes was investigated. TFAF has a high solubility in water (distribution coefficient D is equal to 415) as compared with p-MTFAF, DMTFAF, TMTFAF and TFABAHE (D within 1360 –2700). Hydration occurs most strongly to TFABAHE and is especially strong in alkaline medium. It is established that p-MTFAF and TFABAHE form a crystalline hydrates.

Interaction of sodium dodecyl sulfate with anticancer drug 6-mercaptopurine

Background: 6-Mercaptopurine (6-MP) is used in the conventional chemotherapy of patients with acute lymphoblastic leukemia. Materials and Methods: Sodium dodecyl sulfate (SDS), an anionic surfactant that is commonly used to mimic hydrophobic binding environments such as cell membranes, micellization behavior of sodium dodecyl sulfate (anionic surfactant) has been studied in the presence of 6-MP (anticancer drug) at (1 × 10−5 M) concentrations with different time periods in micelle solution, studied at 37°C. Results: The results showed increase the absorbance values for the pharmaceutical compound (6-MP). Increase the absorbance values of pharmaceutical compounds with 1 × 10−2 critical micelle concentration values of surfactant increase of 6-MP concentrations in micelle solution, with decrease its concentrations in organic media, various thermo-dynamic parameters such as standard-free energy of micellization ΔG (0.6216 k J.mol−1), that have direct bearing on the consequences of such interactions at the molecular level have been calculated. Depend on Keq and slope values for reversible reactions. Conclusion: The above-calculated parameters were found to be sensitive toward the interactions prevailing in 6-MP–SDS–hexane-water systems. After fixed the experimental optimum conditions at pH 7.4, 37°C, and λmax 322 nm.

The use of salting out for the extraction of hydrophilic biologically active substances from the aqueous solutions for their further chromatographic determination

Using gas chromatography methods with the quadrupole mass spectrometric detector and flame ionization detector, as well as high-performance liquid chromatography with the diode-matrix detector, the distribution constants of codeine, phenobarbital, modafinil, adrafinil, pseudoephedrine for hexane-water, hexane-water systems of inorganic salt solutions (sodium chloride, dipotassium phosphate, potassium carbonate and ammonium sulfate), chloroform-water, chloroform-aqueous solutions of inorganic salts (sodium chloride, dipotassium phosphate, potassium carbonate and ammonium sulfate) were determined. The principal possibility of quantitative extraction of all the investigated substances from the aqueous matrices by salting out was shown. The patterns of salting out of the studied substances from the aqueous solutions were established. In particular, the salting out ability of salts increased sharply with the increasing charge of the salt anion. A significant effect on the salting out effect was exerted by the nature of the extracted compound. It has been shown that the following compounds could be quantitatively recovered in the hexane: codeine, modafinil, and afrafinil. Due to their high hydrophilicity, phenobarbital and pseudoephedrine were not quantitatively extracted with the hexane even at the salt concentration close to the saturation. For the extraction of phenobarbital and pseudoephedrine, the more active but less selective chloroform was used. Based on the obtained values of the distribution constants of the substances and their acid-base properties, the extraction methods for the sample preparation of the various objects were proposed with determining the studied substances in them using salting out. The methodology for the determination of pseudoephedrine and codeine in drugs was tested. It was based on the preliminary removal of the matrix components by chloroform from the aqueous acidic solution and subsequent alkalization, salting out, and extraction with chloroform. The characteristics of the methods were as follows: detection limit for pseudoephedrine - 0.09 g/dm 3 and for codeine - 0.07 g/dm 3 ; standard deviation did not exceed 4% for both substances, range of determined concentrations for all-ephedrine was 0.09 – 3.00 g/dm 3 , and for codeine - 0.07 - 4.00 g/dm 3 respectively. Key words : salting out, chromatography, increment of methylene group, solution structure, Sechenov constant (Russian) DOI: http://dx.doi.org/10.15826/analitika.2019.23.4.004 S.M. Leshchev 1 , O.N. Mikhniuk 2 , K.D. Kryzhny 2 , M.F. Zayats 1 1 Belarusian State University, ul. Leningradskaya, 14, Minsk, 220050, Republic of Belarus 2 State institute of advanced training and retraining of customs authorities of the Republic of Belarus, ul. Mogilevskaya, 45/4, Minsk, 220007, Republic of Belarus

INFLUENCE OF THE NATURE OF TRIFLUOROACETOPHENON DERIVATIVES ON SELECTIVITY OF SULFATE AND CARBONATE-SELECTIVE ELECTRODES

UV-spectrophotometric and chromatographic studies of the distribution of trifluoroacetophenone (TFAF) and a number of its derivatives (heptyl ether of p-trifluoroacetylbenzoic acid (HE p-TFABA), p-methyltrifluoroacetophenone (p-MTFAF), 2,4-dimethyltrifluoroacetophenone (DMTFAF), 2,4,6-trimethyltrifluoroacetophenone (TMTFAF)) in a hexane-water system, which simplifies the modeling of a polyvinyl chloride membrane carbonate and sulfate-selective electrodes, were performed. These substances are used as neutral carriers (NC) in membranes of ion-selective electrodes, reversible to double-charged inorganic anions. A systematic study of the hydration of TFAF and a number of its derivatives was carried out. TFAF has increased solubility in water (the distribution coefficient D is 415) as compared to p-MTFAF, DMTFAF, TMTFAF and HE p-TFABA (D within 1360–2700), which does not allow to recommend it as an NC for making electrode membranes. The strongest hydration occurs for the HE p-TFABA in the alkaline medium. It has been found that p-MTFAF and HE p-TFABA form crystalline hydrates. The selectivity coefficients of carbonate and sulfate-selective electrodes were determined for all the NC studied and a number of them were made to improve the selectivity of the electrodes: TFAF k p-MTFAF k DMTFAF k TMTFAF k p-BTFAF (p-buthyltrifluoroacetophenone) k HE p-TFABA.

The effect of modification with fluorescent groups on the physicochemical characteristics of poly(alkylene oxides)

Covalent modification of poly(alkylene oxides), block copolymers of ethylene oxide and propylene oxide with M ∼ 2000, with fluororescein isothiocyanate or 7-nitrobenzo-2-oxadiazole taken in a ratio of 0.6–1.0 mol of label/mole of polymer leads to changes in the physical state of polymers and their solubility in water decreases, as well as the partition coefficient in the hexane-water system and the critical concentration of aggregation and dimensions of the formed particles.

Isolation of myo -Inositol from Solutions by Enzymatic Biotransformation

The transferase reaction between phospholipids and inositol catalyzed by phospholipase D was studied at interfaces in water–organic solvent systems. Optimum conditions were determined for phosphatidylinositol synthesis in heterogeneous water–organic solvent systems. Hydrophobic components (phospholipids) were readily separated from water-soluble products (alcohols) in systems with organic solvents. In the hexane–water system, addition of methanol (an alcohol substrate) to the reaction medium displaced myo-inositol from the molecule of phosphatidylinositol. myo-Inositol was isolated from the mixture of its isomers using a two-step transferase reaction catalyzed by phospholipase D.

Partitioning of alkylphenols and alkylphenol polyethoxylates between water and organic solvents

Partition coefficients of octylphenol (OP), nonylphenol (NP) and nonylphenol ethoxylates (NPnEO, n = 1–3) were determined for n- octanol water and n- hexane water systems. In the octanol/water system, logarithmic values of the partition coefficients (log K OW) for the phenols were 4.12 and 4.48 for OP and NP, respectively. Slightly lower lipophilicity was found for APnEO with log K OW values of NP1EO, NP2EO and NP3EO around 4.2. The corresponding values in hexane/water system were approximately 0.8 logarithmic units lower but showed essentially the same ratio between NP and NPnEO as it was observed in the octanol water system. An attempt was made to estimate octanol/water partition coefficients for higher OPnEO and NPnEO oligomers. Application of reversed-phase HPLC for this purpose resulted in a significant overestimation. Alternatively, octanol/water partition coefficients for the higher APnEO oligomers were estimated (i) using an equation that correlates log K OW with solubility and (ii) converting the respective iso- octane water partition coefficients to the octanol/water coefficients.

Influence of methanol and hexane on soil adsorption of atrazine

The increasing frequency of chemically contaminated groundwater, occurring as a result of improperly managed waste disposal or accidental spills, presents a need for research on the fate of chemical mixtures in the soil. The batch equilibration technique was used to measure adsorption of 14C ring-labeled atrazine (2-chloro-4-ethylamino-6-isopropylamino-s-triazine) for a Palouse silt loam (Pachic Ultic Haploxeroll) and a Pembroke silty clay loam (Typic Paleudalf). The solution phase consisted of mixtures of methanol-water and hexane-water containing up to 33.3 % organic solvent by volume. Aqueous solubility limited atrazine concentrations to 100 μmol L−1 except for an additional isotherm determined in 33.3 methanol-water at up to 1542 μmol L−1 The Freundlich adsorption coefficient indicated that the Palouse adsorbed more atrazine than the Pembroke with K values of 4.95 and 0.54, respectively. Both soils showed a significant decrease in K as the percentage methanol increased. Adsorption isotherms from a 33. 3 methanol-water system were of the Freundlich type for atrazine concentrations of 0.25 to 1542 μmol L−1. In the hexane-water systems, K decreased as the fraction of hexane increased and the Pembroke soil adsorbed less atrazine than the Palouse soil. These results suggest that the introduction of nonaqueous solvents such as methanol and hexane decreased adsorption and increased the potential for atrazine mobility.

Binding of adriamycin-Fe3+ complex to membrane phospholipids.

Binding of adriamycin-Fe3+ complex to phospholipids has been examined by phase partitioning in a hexane-water system. Formation of a stable ternary adriamycin-Fe3+-lipid complex with the negatively charged phospholipids cardiolipin and phosphatidylglycerol (both isolated from Escherichia coli) and synthetic dioleoyl glycerophosphoglycerol is demonstrated. Binding of adriamycin-Fe3+ complex to phospholipid bilayers was assessed by incubation of the complex with aqueous phospholipid dispersions prepared from synthetic dimyristoyl glycerophosphocholine, E. coli phosphatidylethanolamine or E. coli cardiolipin and from mixtures of these lipids. Binding of the complex to the phospholipids took place with an affinity for cardiolipin greater than phosphatidylethanolamine greater than phosphatidylcholine. The ternary adriamycin-Fe3+-ADP complex formed in the presence of 1 mM ADP (ADP in 25-fold molar excess to adriamycin) showed low affinity for binding to phospholipid.