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Articles de revues sur le sujet « MIXED SOLVENT MEDIA »

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Auteur : Grafiati
Publié le 18 mai 2024

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1

A. Mohammed, Abdul-Halim, et Mohammed J. Yass Kheder. « The Effect of Extraction Temperature and Solvent to Oil Ratio on Viscosity Index of Mixed-medium Lubricating Oil Fraction by Using Solvents Extraction ». Iraqi Journal of Chemical and Petroleum Engineering 10, no 2 (30 juin 2009) : 13–18. http://dx.doi.org/10.31699/ijcpe.2009.2.3.

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In this study two types of extraction solvents were used to extract the undesirable polyaromatics, the first solvent was furfural which was used today in the Iraqi refineries and the second was NMP (N-methyl-2-pyrrolidone).The studied effecting variables of extraction are extraction temperature ranged from 70 to 110°C and solvent to oil ratio in the range from 1:1 to 4:1.The results of this investigation show that the viscosity index of mixed-medium lubricating oil fraction increases with increasing extraction temperature and reaches 107.82 for NMP extraction at extraction temperature 110°C and solvent to oil ratio 4:1, while the viscosity index reaches to 101 for furfural extraction at the same extraction temperature and same solvent to oil ratio. The increase in solvent to oil ratio has a higher effect on increasing the viscosity index of lubricating oil fraction compared with extraction temperature in furfural and NMP extraction.Further more, the results show that the percentage yield of raffinate was decreased as the extraction temperature and solvent to oil ratio increases for furfural and NMP extraction.
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2

Vincent, Brian. « Dispersion stability in mixed solvent (aqueous/organic) media ». Advances in Colloid and Interface Science 42 (octobre 1992) : 279–302. http://dx.doi.org/10.1016/0001-8686(92)80025-s.

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3

Yadav, Chandradip Kuma. « A Comparative Study of Conductance of Sodium Dodecyle Sulphate (SDS) in Different Percentage of Ethanol Water Mixed Solvent Media at 298.15 K Temperature ». NUTA Journal 5, no 1-2 (31 décembre 2018) : 67–71. http://dx.doi.org/10.3126/nutaj.v5i1-2.23459.

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Precise measurement of the conductivity of sodium dodecyl sulphate in different percentage of (0%, 10%, 20%) ethanol-water mixed solvent media containing at 298.15 K temperature were measured. The specific conductivities exhibit a sharp increase with increase in concentration with in the concentration range investigated (0.001 to 0.020) mol per liter. The increase in the conductance with concentration is due to an increase in the number of ion per unit volume of the solution. But decrease in conductance with increase in percentage of ethanol - water mixed solvent media at particular temperature 298.15 K. Ionizing effect is decrease with increase in percentage of ethanol - water mixed solvent media at 298.15K. Due to decrease in dielectric constant with increase in percentage of ethanol - water mixed solvent media at particular temperature 298.15 K. conductivity order is 0% > 10% > 20% at particular temperature 298.15 K.
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4

Bhattarai, Ajaya, Kavita Pathak et Bikash Dev. « Micellization behavior of mixed surfactants in pure water and methanol-water mixed solvent media by density methods ». BIBECHANA 13 (3 décembre 2015) : 114–20. http://dx.doi.org/10.3126/bibechana.v13i0.13887.

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The properties of anionic-rich and cationic-rich mixtures of dodecyltrimethylammonium bromide (DTAB) and sodium dodecylsulfate (SDS) in pure water and methanol-water mixed solvent media were studied using density measurements at room temperature. The results showed that density increases with increasing concentration of surfactant mixture over the entire concentration range investigated in pure water and in the given mixed solvent media and which are found to decrease with an increase in the volume fraction of methanol in the solvent composition. The critical micelle concentration increases with the increase in volume fraction of methanol for both the anionic-rich (SDS-DTAB) and cationic-rich (DTAB-SDS) systems.BIBECHANA 13 (2016) 114-120
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5

Basnet, Nabin, et Ajaya Bhattarai. « Conductometric study of nickel chloride in ethanol-water mixed solvent media at various temperatures ». BIBECHANA 12 (20 décembre 2014) : 128–34. http://dx.doi.org/10.3126/bibechana.v12i0.11789.

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The conductivity measurement of nickel chloride has been done in binary solvent of the ethanol-water system. The different percentage of ethanol including 10, 20, 30, 40, 50, 60, 70, 80, 90 and 100 (v/v) has been chosen as binary solvents. The concentration of the electrolyte in the prepared solutions varies from 0.008 to 0.1 mol.l-1 for temperatures 298.15 K, 303.15 K and 308.15 K. The conductivity of the electrolyte decreases with increase in ethanol content in the solvent at a particular temperature, which is due to the decrease in dielectric constant of the medium. The conductivity increases with increase in temperature and concentration, due to increase in mobility of ions and number of ions from observed electrolyte respectively. DOI: http://dx.doi.org/10.3126/bibechana.v12i0.11789BIBECHANA 12 (2015) 128-134
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6

Pathak, Raghvendu. « Solvation enthalpy of uranium tetrachloride in aqueous-alcohols mixed solvents ». Science Vision 17, no 3 (30 septembre 2017) : 122–27. http://dx.doi.org/10.33493/scivis.17.03.01.

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The process of interaction between ions of a solute and the molecules of the solvent through relatively weak covalent bonds is called solvation. It involves evening out a concentration gradient and evenly distributing the solute molecules within the solvent. Hydration is a special case of solvation when the solvent molecules are water. Solvation energy, generally, is the energy released when ions in crystal lattices associate with molecules in a solvent, however it can be positive or negative, depending upon the combined effects of lattice and hydration energies in case of aqueous-ionic solid dissolution. Uranous chloride or uranium tetrachloride (UCl4) is a green crystalline solid which sublimes in vacuum at 500°C/10-3 mm. It is a Lewis acid and hence dissolves in solvents which can act as non-protic Lewis bases. Although dissolution of uranium tetrachloride crystals in water is an exothermic process yielding a green solution which is fairly stable in the cold, yet is hydrolyzed to a considerable extent to furnish an acidic reaction. Solvation enthalpies of quadrivalent uranium system have been scantly reported. The present communication deals with the calculation of enthalpy of solution of uranium tetrachloride in aqueous-non-aqueous solvent mixtures, particularly in 10 and 20 weight (wt) % methyl alcohol-water and ethyl alcohol-water systems at 25°C calorimetrically and thereby estimating the solvation enthalpy of UCl4 in the said media.
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7

Lalitha, Punchayil Velayudhan Nair, et Renganathan Ramaswamy. « A Novel Approach to the Study of Briggs-Rauscher Reaction ». Collection of Czechoslovak Chemical Communications 57, no 11 (1992) : 2235–40. http://dx.doi.org/10.1135/cccc19922235.

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The Briggs-Rauscher reaction with substrates containing acidic hydrogen such as malonic acid, acetonyl acetone has been studied. The employment of mixed media involving an organic solvent and water enabled the study of water-insoluble substrates. The present communication reports the oscillatory behaviour of malonic acid in the iodate system in different mixed media (5 vol.% of the organic solvent) as well as the oscillatory behaviour of seven substrates in acetonitrile-water mixed medium of which two are new substrates hitherto unreported in any of the oscillatory systems.
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8

Shah, Sujit Kumar, Sujeet Kumar Chatterjee et Ajaya Bhattarai. « Micellization of cationic surfactants in alcohol — water mixed solvent media ». Journal of Molecular Liquids 222 (octobre 2016) : 906–14. http://dx.doi.org/10.1016/j.molliq.2016.07.098.

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9

Yadav, Chandradip Kumar, et Brahamdeo Yadav. « Effect of Ethanol on Critical Micelle Concentration of Sodium Dodecylsulphate in Mixed Solvent Media at 308.15K by Conductometric Measurement ». Orchid Academia Siraha 1, no 1 (31 décembre 2022) : 91–102. http://dx.doi.org/10.3126/oas.v1i1.52151.

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The conductivity measurement of sodium dodecyl sulphate (SDS)in mixed solvent media was investigated. The results indicated that sharp increase with the increase in concentration and temperature of sodium dodecyl sulphate the critical micelle concentration (CMC) decreased with the amount of ethanol increase which can be explained based on the nature of solvent mixed media and inter ionic attraction of ions. The graph of conductance versus concentration is used to determine the critical micelle concentration (CMC).
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10

Das, Bijan. « Thermodynamics of electrolytes in mixed solvent media — Application of the Pitzer ion interaction approach ». Canadian Journal of Chemistry 83, no 12 (1 décembre 2005) : 2032–38. http://dx.doi.org/10.1139/v05-222.

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Although for a long time considerable attention has been paid to the application of the Pitzer ion interaction approach to describe the thermodynamic properties of a variety of aqueous electrolyte solutions, such studies in mixed solvent media are still scarce. The present paper discusses the application of the Pitzer ion interaction approach in the case of electrolyte solutions in mixed solvent media. In particular, a comprehensive equation for the thermodynamic properties of hydrochloric acid in dioxane–water mixtures within the temperature range 273.15 to 323.15 K has been generated in the ion interaction (Pitzer) equation form on the basis of electrochemical cell measurements of the hydrochloric acid available in the literature. It was necessary to set varying values of the exponential coefficients α1 and α2 of the standard Pitzer model in different mixed solvent media to achieve a satisfactory fit. The present model quantitatively reproduces the experimental cell electromotive forces over the entire concentration and temperature range used for the experiments. The Pitzer ion interaction approach is, thus, proved to be a very valuable method for the correlation and prediction of thermodynamic properties of electrolytes in mixed solvent media. The implications of the Pitzer ion interaction parameters (β(0), β(1) β(2), and Cϕ) have also been discussed in terms of interionic forces. The present study also stresses the need for additional emf measurements to help interpolation through the dioxane composition. Key words: Pitzer's equations, Pitzer ion interaction parameter, activity coefficients, emf, hydrochloric acid.
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11

Haines, Robert I., Lori Butt, Murray K. Park et Debbie Wheeler. « Oxidation of bis(1,4,7-triazacyclononane)nickel(II) by the peroxodisulphate anion in aqueous and binary aqueous media ». Canadian Journal of Chemistry 71, no 7 (1 juillet 1993) : 976–82. http://dx.doi.org/10.1139/v93-130.

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The kinetics of oxidation of bis(1,4,7-triazacyclononane)nickel(II), [Ni(tacn)2]2+, by the peroxodisulphate anion has been studied in water as a function of S2O82− concentration and temperature. The reaction is first order in both the nickel(II) complex and S2O82−, with a second-order rate constant of 1.13 mol dm−3 s−1 at 298 K. The activation energy for the reaction is 38.3 ± 1.8 kJ mol−1. The reaction was also studied at 298 K in a series of mixed aqueous solvents. Rate retardation relative to water was observed in all solvent mixtures studied. Correlation of the solvent effects on the kinetics of reaction has been made with the free energy of transfer of the initial state and the transition state.
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12

Shrestha, Lalita, Debendra Rai, Prince Subba et Ajaya Bhattarai. « Interaction of Cetylpyridinium Chloride and Methylene Blue in Methanol-Water Solvent Media ». Himalayan Journal of Science and Technology 2 (1 décembre 2018) : 48–52. http://dx.doi.org/10.3126/hijost.v2i0.25843.

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The interaction of Methylene blue with Cetylpyridinium chloride (CPC) in a series of solvents containing 0.1, 0.2 and 0.3 volume fractions of methanol in water were studied at room temp (300±2 K) by UV-Vis spectrophotometer. The CPC concentrations were varied from 0.2 x 10-3 to 2 x 10-3 mol dm-3. A fixed dye concentration of 2.5 x 10-5 mol dm-3 was used for this purpose. The spectrum analysis was performed for both the dye solution and mixtures containing dye and surfactant of different concentrations. The dye solution showed the absorbance maximum at 664 nm and a shoulder at 610 nm. In 0.3 volume fraction of methanol as solvent, the dye and surfactant mixed solution showed a shift in peak values towards shorter wavelength (blue shift) from peak of the dye solution. The shift in peak increased with increase in surfactant concentration up to 0.6 x10-3 mol dm-3, beyond which no further shift increment occurred. In the case of 0.1 and 0.2 volume fractions of methanol in water, no shift in peak was found at all concentrations of dye and surfactant. The absorbance of dye and surfactant mixed solution decreased gradually in 0.2 volume fraction of methanol with increase in surfactant concentration, whereas no significant change in absorbance was seen in 0.1 volume fraction of methanol. The shift decreased gradually with decrease in methanol concentration in the solvent.
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13

Michałowska-Kaczmarczyk, Anna Maria, et Tadeusz Michałowski. « Generalized Electron Balance for Dynamic Redox Systems in Mixed-Solvent Media ». Journal of Analytical Sciences, Methods and Instrumentation 04, no 04 (2014) : 102–9. http://dx.doi.org/10.4236/jasmi.2014.44014.

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14

Aghaie, Mehran, et Roshanak Kishani. « Thermodynamic Investigation of NaClO3 Solubility in the Mixed Solvent Medium and the Related Ion – Pair Formation at Different Temperatures ». Journal of Applied Solution Chemistry and Modeling 4, no 4 (18 décembre 2015) : 173–77. http://dx.doi.org/10.6000/jascm.v4i4.3491.

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Using the evaporating method, the solubility of sodium chlorate was determined in the various mixed solvents (water + ethanol + propanol) at various temperatures. The results showed that the solubility of NaClO3 decreases with increasing the mass percent of ethanol and propanol. On the other hand, the solubility of NaClO3 increases with increasing the temperature. In addition, the equilibrium constant of ion pair formation, KIP, for the reaction Na+(aq) + ClO3-(aq) -->Na+ClO3- (Ion Pair) was estimated upon Fuoss contact ion pair model and then, the values of ion-pair concentrations were determined by using the extended Debye-Hückel model and iteration calculations in various mixed solvents and various temperatures . Finally the value of thermodynamic solubility product constant, Ksp(th), and the values ∆H°, ∆S° and ∆G° of ion-pair formation were estimated in the mixed solvent media.
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15

Shrestha, Prem Kumar, Jaya Narayan Mitruka et Subash Kumar Chapagain. « Micelle Formation in Myristyltrimethyl Ammonium Bromide at Different Solvent Composition of Ethanol Water Mixed Solvent Media ». Journal of Nepal Chemical Society 37 (1 décembre 2017) : 65–68. http://dx.doi.org/10.3126/jncs.v37i0.32149.

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16

Oi, Takao, Akiko Kondoh, Etsuko Ohno et Morikazu Hosoe. « Lithium Isotope Effects in Cation Exchange Chromatography of Lithium Lactate in Water-Dimethyl Sulfoxide and Water-Acetone Mixed Solvent Media ». Zeitschrift für Naturforschung A 48, no 7 (1 juillet 1993) : 811–18. http://dx.doi.org/10.1515/zna-1993-0712.

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Abstract Lithium isotope separation by ion exchange displacement chromatography of lithium lactate in water-dimethyl sulfoxide (DMSO) and water-acetone mixed solvent media at 25 °C was explored. In both the water-DMSO and water-acetone system, the single stage isotope separation factor (S) was a convex function of the mixing ratio of the solvents in the external solution phase; S had its maximum value of 1.00254 at water: DMSO = 25:75 v/v and 1.00182 at water: acetone = 75:25 v/v. Strong correlations of S with solvent partitions between the solution and the exchanger phases were found in both systems, which was qualitatively explainable by considering the lithium isotope distributions between the two phases based on the fundamental lithium isotope effects and the relative affinities of water, DMSO and acetone towards the lithium ion.
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17

Tariq, Muhammad. « Electrochemistry of Br−/Br2 Redox Couple in Acetonitrile, Methanol and Mix Media of Acetonitrile–Methanol : An Insight into Redox Behavior of Bromide on Platinum (Pt) and Gold (Au) Electrode ». Zeitschrift für Physikalische Chemie 234, no 2 (25 février 2020) : 295–312. http://dx.doi.org/10.1515/zpch-2018-1321.

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AbstractElectro-oxidation of Br− on platinum and gold electrode was studied in acetonitrile, methanol and mix media of acetonitrile–methanol. The mechanism of Br− oxidation in these media was investigated using CV, Semi Integration Cyclic Voltammetry, and Digital Simulation technique. Since, Br− oxidation mechanism on platinum involves the formation of Br3− as intermediate, therefore, Kstab for Br3− formation in the mixed media was estimated using digital simulation, Nelson and Iwamoto method. Redox mechanism of Br− and Br2 on gold (Au) electrode was also investigated in protic solvent such as H2O, methanol, ethanol, 1-butanol, and formic acid. It was ascertained that Br− oxidation on gold (Au) electrode in these above protic solvents involve [AuBr2]− intermediate rather than Br3−.
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18

Shah, Sujit Kumar, Tulsi Prasad Niraula, Ajaya Bhattarai et Sujit Kumar Chattarjee. « A comparative study of Critical Micelle Concentration (CMC) and Free Energy of Micellization of cationic surfactant and anionic surfactant in different composition of methanol-water mixed solvent media by conductometric method at 308.15 K ». BIBECHANA 8 (15 janvier 2012) : 37–45. http://dx.doi.org/10.3126/bibechana.v8i0.4883.

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Precise measurements on the specific conductivity of cationic surfactant (Dodecyltrimethyl ammonium bromide) and anionic surfactant (Sodium Dodecyl Sulphate) in methanol water mixed solvent media containing 0.1, 0.2 and 0.3 volume fractions of methanol are reported at 308.15 K. Specific conductivities of Dodecyltrimethyl ammonium bromide and Sodium Dodecyl Sulphate increase with increase in concentration and decrease with increase in the volume fractions of methanol. Critical micelle concentration (cmc) increases with increase in volume fraction of methanol in case of both surfactants. Free energy of micellization (ΔGºm) has been calculated. Increase in cmc with increase in volume fractions of methanol has been explained in terms of breaking of structure of water due to co-solvent effect.Keywords: Critical micelle concentration; methanol-water mixed solvent media; Specific conductivity; Dodecyltrimethylammonium Bromide; Sodiumdodecyl SulphateDOI: http://dx.doi.org/10.3126/bibechana.v8i0.4883 BIBECHANA 8 (2012) 37-45
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19

A.-K. Mohammed, Abdul-Halim, Hussain K. Hussain et Rafal J. Sadiq. « The Effect of Solvent Extraction of Light Lubricating Oil on Viscosity Index and Chemical Composition ». Iraqi Journal of Chemical and Petroleum Engineering 8, no 4 (30 décembre 2007) : 1–12. http://dx.doi.org/10.31699/ijcpe.2007.4.1.

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An investigation was conducted for the improvement of viscosity index of light lubricating oil fraction (40 stock)obtained from vacuum distillation unit of lube oil plant of Daura Refinery, using solvent extraction process.In this study furfural solvent was used to extract the undesirable materials which reduce the viscosity index of rawlubricating oil fraction.The studied effecting variables of extraction were extraction temperature range from 70 to 110°C, and solvent to oilratio range from 1:1 to 4:1 (wt/wt).The n-d-M method was used for calculation of carbon distribution and structural group analysis of the raffinateproduced from furfural extraction.Also the three component phase diagram for a mixed-base oil and furfural at different temperature was drawn.The results of this investigation show that the viscosity index of lubricating oil fraction increases with increasingextraction temperature and increasing the solvent to oil ratio and reaches 115.6 at extraction temperature 110°C andsolvent to oil ratio 4:1.Further more, the results show that the viscosity, refractive index, density, sulfur content and percentage yield ofproduced raffinate were decreased as the extraction temperature or solvent to oil ratio increases for extraction process.
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20

Oconnor, J., A. Aggett, DR Williams et RA Stanley. « Candida cylindracea Lipase-Catalyzed Hydrolysis of Methyl Palmitate in Detergentless Microemulsion and Paraffin/Water Biphasic Media ». Australian Journal of Chemistry 44, no 1 (1991) : 53. http://dx.doi.org/10.1071/ch9910053.

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The activity of lipase from Candida cylindracea has been investigated in the detergentless microemulsion media of n-hexane/propan-2-ol/water and in paraffin/water biphasic mixtures. Analysis of the product of hydrolysis, palmitic acid, was by a titrimetric method developed for non-specific assay of free fatty acids in these mixed-solvent media. The enzyme-catalysed hydrolysis of methyl palmitate was very slow in a complete non-aqueous system, but addition of small amounts of water led to an increased rate of reaction at atmospheric pressure and 37°C. The ability of the enzyme to work in these mixed-solvent systems under very favourable experimental conditions makes it particularly amenable to practical and cost-effective transformations.
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21

Farhan, Laith Warid, Faleh H. M. Almahdawi et Adel Sherif Hammadi. « Dissolving Precipitated Asphaltenes Inside Oil Reservoirs Using Local Solvents ». Iraqi Journal of Chemical and Petroleum Engineering 21, no 1 (29 mars 2020) : 45–52. http://dx.doi.org/10.31699/ijcpe.2020.1.7.

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There are several oil reservoirs that had severe from a sudden or gradual decline in their production due to asphaltene precipitation inside these reservoirs. Asphaltene deposition inside oil reservoirs causes damage for permeability and skin factor, wettability alteration of a reservoir, greater drawdown pressure. These adverse changing lead to flow rate reduction, so the economic profit will drop. The aim of this study is using local solvents: reformate, heavy-naphtha and binary of them for dissolving precipitated asphaltene inside the oil reservoir. Three samples of the sand pack had been prepared and mixed with a certain amount of asphaltene. Permeability of these samples calculated before and after mixed with asphaltenes. Then, the permeability of samples calculated after solvents injection into that porous media. After that, all the values of samples permeability converted to average permeability damage compared with the pure samples. The results show the average permeability damage of samples that mixed with 20 gm was 24 %, but after reformate injected reduced to 14 %. After injected heavy naphtha to porous media, the average permeability reduced only to 17%. The binary solvent had been prepared from reformatted mixed with heavy naphtha gained the best results because it dropped the average permeability damage to 10%.
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Hirotsu, Shunsuke. « Phase Transition of a Polymer Gel in Pure and Mixed Solvent Media ». Journal of the Physical Society of Japan 56, no 1 (15 janvier 1987) : 233–42. http://dx.doi.org/10.1143/jpsj.56.233.

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23

Aimin, Zhao, Zhang Yanlin et Wang Luhuan. « Ion exchange of uranium(IV) in hydrochloric acid—Organic solvent mixed media ». Journal of Radioanalytical and Nuclear Chemistry Articles 143, no 2 (décembre 1990) : 365–71. http://dx.doi.org/10.1007/bf02039604.

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24

Niraula, Tulasi Prasad, Ajaya Bhattarai et Sujeet Kumar Chatterjee. « Effects of concentration, relative permittivity on the transport properties of Sodium dodecyl sulphate in presence and in absence of potassium bromide and Sodium chloride in methanol-water mixed solvent media at 308. 15 K ». BIBECHANA 9 (10 décembre 2012) : 159–64. http://dx.doi.org/10.3126/bibechana.v9i0.7191.

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Precise measurements on conductivity of sodium dodecyl sulphate in presence and in absence of KBr and NaCl in methanol-water mixed solvent media containing 0.1, 0.2 and 0.4 volume fractions of methanol at 308.15K are reported. The concentrations were varied from ~ 0.001 to ~ 0.03 mol.l-1. The results showed a sharp increase in conductivity with increase in concentration of sodium dodecyl sulphate. Also, the conductivity of sodium dodecyl sulphate increases with addition of salts. The conductivity of sodium dodecyl sulphate decreases with increase in amount of methanol. The conductance of sodium dodecyl sulphate is found more in presence of KBr than NaCl in methanol-water mixed solvent media containing 0.1, 0.2 and 0.4 volume fractions of methanol. DOI: http://dx.doi.org/10.3126/bibechana.v9i0.7191 BIBECHANA 9 (2013) 159-164
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25

Hassan, Ahmed, H. A. Azab, S. A. El Gyar et Z. A. Khafagy. « Medium effect on the second-stage dissociation constant of N-(2-acetamido)imino diacetic acid (H2ADA) ». Canadian Journal of Chemistry 70, no 6 (1 juin 1992) : 1684–87. http://dx.doi.org/10.1139/v92-211.

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The second-stage dissociation constant values of N-(2-acetamido)imino diacetic acid (H2ADA) were determined at 25 ± 0.1 °C by potentiometric titration in different mixed-solvent mixtures (methanol, ethanol, dimethylformamide (DMF), dimethyl sulfoxide (DMSO), acetone, and dioxane). It was observed that the pKa value is slightly influenced as the solvent is enriched in methanol and ethanol, and remains practically constant in the presence of different amounts of DMF and DMSO. A prounounced change in the pKa value was observed as the solvent is enriched in acetone or dioxane. These results are discussed in terms of various solvent characteristics. It is concluded that the electrostatic effect has only a relatively small influence on the dissociation equilibrium of the imino group [Formula: see text]. Other solvent effects such as solvent basicity, different stabilization of the free base of the conjugate acid by hydrogen bonding interactions in aquoorganic solvent media relative to pure aqueous media, as well as proton–solvent interaction play an important role in the acid dissociation equilibrium.
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Su, Chien-You, Han-Liou Yi, Li-Duan Tsai, Ming-Chou Chen et Chi-Chung Hua. « Solution properties of imidazolium-based amphiphilic polyelectrolyte in pure- and mixed-solvent media ». Physical Chemistry Chemical Physics 21, no 7 (2019) : 3960–69. http://dx.doi.org/10.1039/c8cp07027j.

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Das, Bijan, et Amritendu Chatterjee. « Salt-induced counterion condensation and related phenomena in sodium carboxymethylcellulose–sodium halide–methanol–water quaternary systems ». Soft Matter 11, no 20 (2015) : 4133–40. http://dx.doi.org/10.1039/c5sm00535c.

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Transport and frictional behaviour of sodium carboxymethylcellulose dissolved in methanol–water mixed solvent media with varying volume fractions (v) of methanol have been investigated conductometrically in presence of different concentrations of NaCl and NaBr.
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Ganaie, Nadeem Bashir, et Ghulam Mustafa Peerzada. « Dynamical regime of resorcinol based Belousov–Zhabotinsky chemical oscillator in the presence or absence of some hydrophobic antioxidants in aqueous–organic mixed media ». RSC Advances 7, no 22 (2017) : 13019–31. http://dx.doi.org/10.1039/c6ra25351b.

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Feng, Qiao, Ya Qi Zhao et Xiang Chen. « Porous Poly(N-Isopropylacrylamide) Gels Frontal Polymerized in Mixed Solvents of Ethanol and Dimethylsulfoxide ». Advanced Materials Research 554-556 (juillet 2012) : 240–43. http://dx.doi.org/10.4028/www.scientific.net/amr.554-556.240.

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The thermo-responsive hydrogels poly(N-isopropylacrylamide) (PNIPAm) were synthesized by frontal polymerization (FP) in dimethylsulfoxide (DMSO) and ethanol mixture. The effects of composition of synthesis-solvent on FP feature and porous morphologies as well as their response behavior of the final products were studied. PNIPAm hydrogel synthesized in mixture exhibited a porous structure, which was responsible for its higher swelling ratio. Moreover, an improvement in swelling capability of the final PNIPAm hydrogel was found when the ethanol content in mixed media was elevated. The approach, frontal polymerization in mixed solvent, reported here provides a promising option to synthesize porous intelligent hydrogels PNIPAm.
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Bhattarai, Ajaya, Sujit Kumar Shah et Ashok Kumar Yadav. « Effect of Solvent Composition on the Critical Micelle Concentration of Cetylpyridinium Chloride in Ethanol-Water Mixed Solvent Media ». Nepal Journal of Science and Technology 13, no 1 (21 janvier 2013) : 89–93. http://dx.doi.org/10.3126/njst.v13i1.7446.

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The accurate measurement of the specific conductivity of cetylpyridinium chloride in pure water and ethanol-water mixed solvent media containing 0.10, 0.20, 0.30 and 0.40 volume fraction of ethanol at room temperature are reported. The concentrations were varied from ~ 0.005 mol l-1 to ~ 0.0002 mol l-1.The conductivity of cetylpyridinium chloride decreases with the increase in the volume fraction of ethanol. The critical micelle concentration of cetylpyridinium chloride increases with the increase in the volume fraction of ethanol. Nepal Journal of Science and Technology Vol. 13, No. 1 (2012) 89-93 DOI: http://dx.doi.org/10.3126/njst.v13i1.7446
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Bhattarai, Ajaya, Sujit Kumar Shah, Ashok Kumar Yadav et Janak Adhikari. « Effect of solvent composition on the critical micelle concentration of sodium deoxycholate in ethanol-water mixed solvent media ». BIBECHANA 9 (10 décembre 2012) : 63–68. http://dx.doi.org/10.3126/bibechana.v9i0.7176.

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The precise measurement of the specific conductivity of sodium deoxycholate in pure water and ethanolwater mixed solvent media containing 0.10 and 0.20 volume fraction of ethanol at 303.15 K are reported. The concentration were varied from ~ 0.01 mol L-1 to ~ 0.0002 mol L-1.The conductivity of sodium deoxycholate decreases with the increase in the volume fraction of ethanol. The critical micelle concentration of sodium deoxycholate increases with the increase in the volume fraction of ethanol. DOI: http://dx.doi.org/10.3126/bibechana.v9i0.7176 BIBECHANA 9 (2013) 63-68
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Bhattarai, Ajaya. « Investigation on solution properties of surfactants in mixed solvent media : Landmark towards Surface Chemistry in Eastern Nepal ». BIBECHANA 11 (10 mai 2014) : 175–80. http://dx.doi.org/10.3126/bibechana.v11i0.10400.

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Surfactants are amphiphilic molecules having a hydrophilic or water soluble moiety (head group) and a hydrophobic, or water insoluble moiety (tail group). Surfactants are not only related to soaps and detergents, they are also in heavy demand for industrial processes requiring colloid stability, metal treatments, mineral flotation, pesticides, oil production, pharmaceutical formulation, emulsion polymerization, particle growth and many more. That is why surfactants have been and continue to be a very active area of scientific research and commercial growth for several decades. One interesting property of surfactants is that at low concentrations, they exist solely as monomers. The formation of micelles, begins at a specific surfactant concentration termed the critical micelle concentration (cmc), where the physical properties of the solution, such as interfacial tension, electrical conductivity, and light scattering behaviour, often changes abruptly due to the existence of micelles. The formation of micelles will be able to calculate various thermodynamic parameters. These parameters make surfactants not only an interesting and rich area for the exploration of novel phenomena but also an area of research which can lead to new applications in a variety of fields. However, most of the previous studies on surfactants are limited to aqueous media only. Studies in mixed solvent media are very natural one as one can modulate the conformations of surfactants and their interactions easily by simply varying the composition of the media. With this concept, the research team of Eastern Nepal has started to work the solution properties of surfactants in different mixed solvent media in presence and absence of salts and has also investigated cationic and anionic surfactant interaction in mixed solvent media. DOI: http://dx.doi.org/10.3126/bibechana.v11i0.10400 BIBECHANA 11(1) (2014) 175-180
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Bhattarai, Ajaya, Kavita Pathak et Bikash Dev. « Cationic and anionic surfactants interaction in water and methanol–water mixed solvent media ». Journal of Molecular Liquids 229 (mars 2017) : 153–60. http://dx.doi.org/10.1016/j.molliq.2016.12.021.

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Lee, Burtrand I., et Ungyu Paik. « Dispersion of alumina and silica powders in non-aqueous media : Mixed-solvent effects ». Ceramics International 19, no 4 (1993) : 241–50. http://dx.doi.org/10.1016/0272-8842(93)90056-w.

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Debnath, Bidyut, Gulmi Chakraborty et Swapan K. Saha. « Solution and rheological properties of polyacrylamide in 1,4-dioxane + water mixed solvent media ». Journal of Macromolecular Science, Part A 57, no 9 (15 avril 2020) : 628–35. http://dx.doi.org/10.1080/10601325.2020.1747357.

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Chatterjee, Amritendu, Bijan Das et Chanchal Das. « Polyion–counterion interaction behavior for sodium carboxymethylcellulose in methanol–water mixed solvent media ». Carbohydrate Polymers 87, no 2 (janvier 2012) : 1144–52. http://dx.doi.org/10.1016/j.carbpol.2011.08.087.

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Brusova, Zuzana, Elena?E Ferapontova, Ivan?Yu Sakharov, Edmond Magner et Lo Gorton. « Bioelectrocatalysis of Plant Peroxidases Immobilized on Graphite in Aqueous and Mixed Solvent Media ». Electroanalysis 17, no 5-6 (mars 2005) : 460–68. http://dx.doi.org/10.1002/elan.200403182.

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Abdollahi, Hamid, et Hamid Babamoradi. « Rank deficiency in spectrophotometric study of acid dissociation equilibria in mixed solvent media ». Chemometrics and Intelligent Laboratory Systems 98, no 1 (août 2009) : 58–64. http://dx.doi.org/10.1016/j.chemolab.2009.04.010.

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Zohuriaan-Mehr, M. J., K. Kabiri et M. Kheirabadi. « Extraordinary swelling behavior of poly(AMPS) organogel in solvent/DMSO binary mixed media ». Journal of Applied Polymer Science 117, no 2 (15 juillet 2010) : 1127–36. http://dx.doi.org/10.1002/app.31912.

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Shah, Sujit Kumar, Sujeet Kumar Chatterjee et Ajaya Bhattarai. « Effect of Methanol on Viscosity of Aqueous Solutions of Cationic Surfactants at 298.15 to 323.15 K ». Journal of Chemistry 2016 (2016) : 1–5. http://dx.doi.org/10.1155/2016/2176769.

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Viscosity measurements have been made to the solutions of dodecyltrimethylammonium bromide (DTAB) and cetyltrimethylammonium bromide (CTAB) in 0.10, 0.20, 0.30, and 0.40 volume fractions of methanol in methanol-water mixed solvent media at 298.15, 308.15, 318.15, and 323.25 K. Critical micelle concentration (CMC) values have been determined. From relative viscosity for surfactant solutions, related viscosityBcoefficients are calculated and the values are interpreted in terms of solute-solvent interactions.
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Snigur, D. V., A. N. Chebotarev, T. M. Shcherbakova, E. M. Rakhlytskaya et V. V. Shapovalenko. « IONIZATION OF ETHANOLAMINES IN WATER- ORGANIC MEDIA ». Odesa National University Herald. Chemistry 28, no 1(84) (10 mai 2023) : 53–57. http://dx.doi.org/10.18524/2304-0947.2023.1(84).277061.

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In this paper, the ionization constants (pKa) of some nitrogen-containing organic bases (monoethanolamine, diethanolamine and triethanolamine) in water-ethanol, water-acetone and water-acetonitrile solutions at various concentrations of organic solvent in the studied systems have been determined by the potentiometric titration method. It was found that the values of pKa of monoethanolamine, diethanolamine and triethanolamine in aqueous-organic solutions naturally decreases with increasing concentration of organic solvent in the system. It was shown that their nature and the physico-chemical properties of the medium are significantly influenced by the nature and degree of change in the electron donor ability of the studied nitrogen-containing organic bases. It should be noted that for the studied nitrogen-containing organic bases (monoethanolamine, diethanolamine and triethanolamine), when passing from an aqueous medium to an organic one (ethanol or acetone or acetonitrile), the pKa values naturally decrease with an increase in the content of the organic solvent in the system. In general, in the transition from an aqueous medium to an organic one (ethanol or acetone or acetonitrile), a change in pKa can reach 1.73 units. It was established that the dependence of the values of pKa of nitrogen-containing organic bases which were determinate via potentiometric titration method on the inverse of the dielectric constant of water-ethanol and water-acetone or water-acetonitrile solutions tends to be linear, consistent with Izmailov’s theory. Thus, we can conclude that the change in the ratio of the mixed solvent components and, as a result, in general, dielectric permeability of the medium does not lead to a significant change in the solvation characteristics of the studied nitrogen-containing organic bases.
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Faraji, Mohammad, Ali Farajtabar, Farrokh Gharib et Hassan Ghasemnejad-Borsa. « Deprotonation of salicylic acid and 5-nitrosalicylic acid in aqueous solutions of ethanol ». Journal of the Serbian Chemical Society 76, no 11 (2011) : 1455–63. http://dx.doi.org/10.2298/jsc100506129f.

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The protonation constant values of two hydroxybenzoic acids (salicylic and 5-nitrosalicylic acid) were studied in some water-ethanol solutions using spectrophotometric and potentiometric methods at 25?C and in an ionic strength of 0.1 M sodium perchlorate. The results indicated that the pKa values increase with increasing proportion of ethanol in mixed solvent. The dependence of the protonation constants on the variation of the solvent were correlated by the dielectric constants of the media. Furthermore, for a better understanding of the solvent influence, the obtained results were explained in terms of the Kamlet-Taft parameters ? (hydrogen-bond donor acidity), ?
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Ivanov, Evgeny, Elena Lebedeva, Arina Pakina et Nadezhda Ivanova. « Comparative description of the extraordinary phenomenon "thermally activated isobaric partial structure compaction" of water as a solute in some alkanols and alkylamines ». From Chemistry Towards Technology Step-By-Step 5, no 1 (23 mars 2024) : 85–106. http://dx.doi.org/10.52957/2782-1900-2024-5-1-85-106.

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This review summarises the data available in the literature. It also includes the authors' published results of precision densimetric measurements. The research concerns with the physically unusual phenomenon of "thermally activated isobaric partial densification of the structure" (TIPCS) of dissolved water, or its so-called "negative partial molar expandability" (NPEA) in several organic solvents. They contain amphiproton hydroxyl-containing media of three alcohols: methyl alcohol (MA), tertiary butyl alcohol (TBAlcohol), and amyl or pentyl alcohol (TPA), so asprotophilic media of two amines: tert butylamine (TBAmine) and ethylenediamine (EDA). The discussed TIPCS phenomenon, associated with a decrease in the standard (partial at infinite dilution) volume of solvated water with increasing temperature, was discovered about half a century ago in alkanol solutions of H2O and recently - in water-containing media of alkylamines. However, nowadays this extraordinary effect has not yet found its physically based interpretation. It allows ones to predict the possibility of TIPCS occurrence in the binary liquid-phase system specifically selected for the study. Our comprehensive data analysis allowed us to make several inferences regarding the main characteristics of a standard solution of H2O in an organic solvent. They cause extraordinary changes in the volume of the formed solvatocomplex of water under the influence of increasing temperature. Firstly, the energy parameters of the intermolecular interaction (relative affinity) water solvent noticeably dominate over those of the solvent-solvent interaction. Those differences become more evident with increasing temperature. Secondly, a higher rate of thermal expansion of the organic solvent structure in volume (inbulk) is found than influence of temperature on structural packing of the resulting mixed molecular aggregate or water solvates complex. Thirdly, the difference in the parameters of water-solvent and solvent-solvent interactions depends not only on the proton-donor/acceptor properties of the molecules contacting in solution, but also on the configuration of the structural packing of the solvating medium. It determines the nature of steric hindrances to the formation of H-bonds. Therefore, the absolute values of the mentioned parameters of relative affinity at 298.15 K increase in the series: MA << EDA ≈ TBAmine < TPAlcohol < TBAmine. It can indicate a relative strengthening of the specific interaction (mainly through the formation of hydrogen bonds) between the molecules of water and amphiprotonic or protophilic solvent in the above sequence. Indeed, difference in the solvent-solvent and water-solvent hydrogen bonding energies in the discussed liquid media of alkylamines (TBAmine and EDA) and tertiary isomeric alkanols (TBAlcohol and TPA) - with the most evident basicity - turned out to be noticeably larger than in the structural packing of water methanol solution. The ability of the components to specific interactions is quite comparable in those compounds.
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Ivanov, Evgeny, Elena Lebedeva, Arina Pakina et Nadezhda Ivanova. « Comparative description of the extraordinary phenomenon "thermally activated isobaric partial structure compaction" of water as a solute in some alkanols and alkylamines ». From Chemistry Towards Technology Step-By-Step 5, no 1 (23 mars 2024) : 8–32. http://dx.doi.org/10.52957/2782-1900-2024-5-1-8-32.

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This review summarises the data available in the literature. It also includes the authors' published results of precision densimetric measurements. The research concerns with the physically unusual phenomenon of "thermally activated isobaric partial densification of the structure" (TIPCS) of dissolved water, or its so-called "negative partial molar expandability" (NPEA) in several organic solvents. They contain amphiproton hydroxyl-containing media of three alcohols: methyl alcohol (MA), tertiary butyl alcohol (TBAlcohol), and amyl or pentyl alcohol (TPA), so asprotophilic media of two amines: tert butylamine (TBAmine) and ethylenediamine (EDA). The discussed TIPCS phenomenon, associated with a decrease in the standard (partial at infinite dilution) volume of solvated water with increasing temperature, was discovered about half a century ago in alkanol solutions of H2O and recently - in water-containing media of alkylamines. However, nowadays this extraordinary effect has not yet found its physically based interpretation. It allows ones to predict the possibility of TIPCS occurrence in the binary liquid-phase system specifically selected for the study. Our comprehensive data analysis allowed us to make several inferences regarding the main characteristics of a standard solution of H2O in an organic solvent. They cause extraordinary changes in the volume of the formed solvatocomplex of water under the influence of increasing temperature. Firstly, the energy parameters of the intermolecular interaction (relative affinity) water solvent noticeably dominate over those of the solvent-solvent interaction. Those differences become more evident with increasing temperature. Secondly, a higher rate of thermal expansion of the organic solvent structure in volume (inbulk) is found than influence of temperature on structural packing of the resulting mixed molecular aggregate or water solvates complex. Thirdly, the difference in the parameters of water-solvent and solvent-solvent interactions depends not only on the proton-donor/acceptor properties of the molecules contacting in solution, but also on the configuration of the structural packing of the solvating medium. It determines the nature of steric hindrances to the formation of H-bonds. Therefore, the absolute values of the mentioned parameters of relative affinity at 298.15 K increase in the series: MA << EDA ≈ TBAmine < TPAlcohol < TBAmine. It can indicate a relative strengthening of the specific interaction (mainly through the formation of hydrogen bonds) between the molecules of water and amphiprotonic or protophilic solvent in the above sequence. Indeed, difference in the solvent-solvent and water-solvent hydrogen bonding energies in the discussed liquid media of alkylamines (TBAmine and EDA) and tertiary isomeric alkanols (TBAlcohol and TPA) - with the most evident basicity - turned out to be noticeably larger than in the structural packing of water methanol solution. The ability of the components to specific interactions is quite comparable in those compounds.
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Niraula, Tulasi Prasad, Sujeet Kumar Chatterjee et Ajaya Bhattarai. « Conductance of Sodium dodecyl sulphate in Presence and in Absence of KCl and NaBr in Methanol-Water mixed solvent media at 308. 15 K ». Journal of Nepal Chemical Society 29 (3 décembre 2013) : 5–10. http://dx.doi.org/10.3126/jncs.v29i0.9230.

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Correction: On 10/01/2014, the first author of this paper was changed from Tulsi Ram Niraula to Tulasi Prasad NiraulaPrecise measurements on conductivity of sodium dodecyl sulphate in presence and in absence of KCl and NaBr in methanol-water mixed solvent media containing 0.1, 0.2, 0.3, and 0.4 volume fractions of methanol at 308.15K are reported. The concentrations were varied from ~ 0.001 to ~ 0.05 mol-1. The results showed a sharp increase in conductivity with increase in concentration of sodium dodecyl sulphate. Also,the conductivity of sodium dodecyl sulphate increases with addition of salts. The conductivity of sodium dodecyl sulphate decreases with increase in amount of methanol. The conductance of sodium dodecyl sulphate is found more in presence of KCl than NaBr in methanol-water mixed solvent media containing 0.1, 0.2, 0.3, and 0.4 volume fractions of methanol. DOI: http://dx.doi.org/10.3126/jncs.v29i0.9230Journal of Nepal Chemical SocietyVol. 29, 2012Page: 5-10Uploaded date : 12/3/2013
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Glatzhofer, Daniel T., et Rahul S. Kadam. « Use of Electron Paramagnetic Resonance Spectroscopy to Study Dielectric Properties of Liquids ». ISRN Analytical Chemistry 2012 (9 avril 2012) : 1–8. http://dx.doi.org/10.5402/2012/847102.

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The signal response of an EPR active species is attenuated by the medium it is in. Keeping all other parameters the same, the higher the dielectric constant of the medium, the lower the EPR signal response. This behavior is problematic in studying EPR active species in high dielectric media but can be capitalized upon to monitor changes in the dielectric constant or estimate the dielectric constant of the medium. Using a coaxial EPR cell design, the EPR signal of a stable nitroxyl radical compound (2,2,6,6-tetramethyl-piperidin-1-oxyl radical) in a low dielectric constant solvent in an inner tube is attenuated by the solvent present between the inner and outer tubes (jacket medium). The attenuation increases monotonically with an increase in the dielectric constant of the jacket medium. Calibration curves can be constructed using jacket media of known dielectric constants ranging from 2 to 80 and the dielectric constant of a sample used as the jacket medium can be estimated by interpolation. This technique is applied to estimate the dielectric constants and/or composition of mixed solvents and to monitor the rate of a reaction.
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Homocianu, Mihaela, Alina Mirela Ipate, Daniel Homocianu, Anton Airinei et Corneliu Hamciuc. « Effects of solvating media of some phenylquinoxaline derivatives on their photophysical properties. Mixed solvent systems and acidic media ». Journal of Molecular Liquids 247 (décembre 2017) : 14–21. http://dx.doi.org/10.1016/j.molliq.2017.09.102.

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Ali, Jamshed, Mustafa Tuzen et Tasneem G. Kazi. « Evaluation of Mercury in Environmental Samples by a Supramolecular Solvent–Based Dispersive Liquid–Liquid Microextraction Method Before Analysis by a Cold Vapor Generation Technique ». Journal of AOAC INTERNATIONAL 100, no 3 (1 mai 2017) : 782–88. http://dx.doi.org/10.5740/jaoacint.16-0252.

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Abstract Supramolecular solvent–based dispersive liquid–liquid microextraction was used as a preconcentration method for the determination of trace levels of Hg. This simple method accurately measured oxidized HgII content inclaystone and sandstone samples obtained from the Thar Coalfield in Pakistan. Cold vapor atomic absorption spectrometry was used as the detection technique because it is reliable and accurate. The HgII in acidic media forms a complexwith dithizone (DTz) in the presence of supramolecular solvent (tetrahydrofuran and 1-undecanol), forming reverse micelles. Formation of the Hg-DTz complex was achieved to increase the interactions with the supramolecular solvent phase at pH 2.5 under the optimized experimental conditions. After additionof the supramolecular solvent to the aqueous solution, the micelles were uniformly mixed using a vortex mixer. The cloudy solution was centrifuged, and the Hg-DTz complex was extracted into the supramolecular solvent phase. Under optimized experimental conditions, the LOD and enrichment factor were foundto be 5.61 ng/L and 77.8, respectively. Accuracy of the developed method was checked with Certified Reference Materials. The developed method was successfully applied for the determination of HgII in claystone and sandstone samples from the Block VII and Block VIII areas of the Thar Coalfield on the basis of depth.
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Sivaraj, Kumarasamy, et Kuppanagounder P. Elango. « Differential Pulse Voltammetric Studies of Some Mixed-ligand Co(III) Complexes in Aquo-Organic Solvent Media Possessing Different Hydrogen Bonding Properties ». Zeitschrift für Naturforschung B 64, no 9 (1 septembre 2009) : 1021–26. http://dx.doi.org/10.1515/znb-2009-0905.

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The electro-reduction of a series of Co(III) complexes of the type cis-β -[Co(trien)(4-R-Py)Cl]Cl2, where trien = triethylenetetramine and R = H, Me, Et, t-Bu, COMe, and CN, has been studied in propan-2-ol/water and 1,4-dioxane/water binary mixtures. The redox potential (E1/2) data were correlated with solvent and structural parameters with an aim to shed some light on the mechanism of these reactions. Correlation of E1/2 with macroscopic solvent parameters indicated that the reactivity is influenced by both specific and non-specific solute-solvent interactions. The reduction of Co(III) to Co(II) in these complexes was observed to become increasingly easier with an increase in the dipolarity/ polarizability of the medium as evidenced by the Kamlet-Taft correlation. The difference in the relative lenience of the reduction has been explained using the difference in H-bonding properties of the medium.
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Bhattarai, Ajaya, et Sanjay Neupane. « Effects of concentration and solvent composition on the electrical conductivity of sodium bromide in pure water and ethanol-water mixed solvent media ». Kathmandu University Journal of Science, Engineering and Technology 8, no 2 (3 janvier 2013) : 1–6. http://dx.doi.org/10.3126/kuset.v8i2.7318.

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Precise measurements on the conductivity of Sodium Bromide in pure water and ethanol-water mixed solvent media containing 0.10, 0.20, 0.30, 0.40, 0.50 and 0.60 volume fractions of ethanol at room temperature are reported. The concentrations were varied from ~ 0.010 to ~ 0.10 mol.L-1. The results showed a sharp increase in the conductivity with increasing electrolyte concentration. The conductivity of electrolyte decreases with increase in the amount of ethanol.Kathmandu University Journal of Science, Engineering and Technology Vol. 8, No. II, December, 2012, 1-6 DOI: http://dx.doi.org/10.3126/kuset.v8i2.7318
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