Zeitschriftenartikel: „Theory of mixed solvent“

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Wang, Jianji, Yang Zhao, Kelei Zhuo und Ruisen Lin. „Viscosity Properties of Electrolytes in Propylene Carbonate Based Lithium Battery Electrolyte Solutions“. Zeitschrift für Physikalische Chemie 217, Nr. 6 (01.06.2003): 637–52. http://dx.doi.org/10.1524/zpch.217.6.637.20445.

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AbstractViscosities of LiClO4 and LiBr have been measured in solvent mixtures of propylene carbonate (PC) with dimethylformamide (DMF), tetrahydrofuran (THF), acetonitrile (AN) and methyl formate (MF) at 298.15K. The dependence of viscosity on the composition of the mixed solvents was fitted with an equation without adjustable parameter. Viscosity B-coefficients for lithium salts and the corresponding activation free energies (Δμ0,≠) for viscous flow have been evaluated. At the same time, viscosity B-coefficients were predicted by the dielectric friction theory. The unsuccessful prediction of the composition dependence of the B-coefficients indicates that improvements will be necessary on the theory with taking account of the short-range interaction and molecular nature of the solvents. Furthermore, solute–solvent interactions in these mixed solvents are discussed in terms of the B-coefficients and activation parameters.

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Tyunina, E. Yu, und M. D. Chekunova. „LiAsF6 SOLUTIONS IN THE MIXED SOLVENTS OF PROPYLENE CARBONATE – DIMETHYL SULFOXIDE: ELECTRIC CONDUCTIVITY AND ELECTROCHEMICAL STABILITY“. Электрохимия 59, Nr. 12 (01.12.2023): 872–83. http://dx.doi.org/10.31857/s0424857023120137.

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The specific conductivities of LiAsF6 solutions in a mixed solvent of propylene carbonate (PC) –dimethyl sulfoxide (DMSO) were measured at temperatures of 253.15, 263.15, 273.15, 283.15, 293.15, 303.15, 313.15, 323.15 and 333.15 K being a ionophore concentration of 0.2 to 1.4 mol / kg. The portion of DMSO in the mixed solvent was varied in the range of (0.2 - 0.75) mole fractions. The specific conductivities of LiAsF6 in DMSO were studied in the temperature range of (293.15 – 333.15) K. Concentration dependences of specific conductivity of the system can be described by the Casteel-Amis equation. The contributions of the solvent and ionophore to the activation energy of the ionic conduction process are determined on the base of the transition state theory. It has been found that the LiAsF6 solutions in a mixed PC – DMSO solvent have a narrower electrochemical window compared to the solutions of this ionophore in pure PC and DMSO solvents.

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Xiao, Rui, Jin Qian und Shaoxing Qu. „Modeling Gel Swelling in Binary Solvents: A Thermodynamic Approach to Explaining Cosolvency and Cononsolvency Effects“. International Journal of Applied Mechanics 11, Nr. 05 (Juni 2019): 1950050. http://dx.doi.org/10.1142/s1758825119500509.

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If gel swells in binary solvents, two unusual phenomena may appear. Two solvents with relatively low swelling ability may become a good solvent for the polymer with high swelling ability when mixed, which is known as a cosolvency effect. In contrast, a cononsolvency effect indicates polymer is less soluable in solvent mixtures than it is in each of the cosolvents. In this work, we develop a thermodynamic theory to describe the equilibrium swelling behaviors of gels in binary solvents based on the Flory–Huggins lattice model. The model can reproduce both cosolvency and cononsolvency effects, showing that these effects are caused by the preferential absorption of the solvent by polymer together with solvent–solvent interactions. The model is also applied to describe experimentally observed cosolvency and cononsolvency effects in the literature, which shows an acceptable agreement.

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Anderson, Lester, Evan Yu und Wan-Ting Chen. „Chemical Recycling of Mixed Plastics in Electronic Waste Using Solvent-Based Processing“. Processes 10, Nr. 1 (29.12.2021): 66. http://dx.doi.org/10.3390/pr10010066.

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Currently, less than 20% of electronic waste (E-waste) produced in the U.S. is recycled. To improve the recycling rate of E-waste, the study aimed to: (1) identify the major plastics found within electronic shredder residue (ESR), (2) design solvents and processing conditions capable of separating out 90% of the plastic in ESR, and (3) estimate the energy efficiency of the solvent-based process developed. Preliminary screening showed 25 wt.% of the ESR was composed of plastics, with two polymers dominating the sorted plastic fraction—polystyrene (PS, 40 wt.%) and acrylonitrile butadiene styrene (ABS, 25 wt.%). Subsequently, solvents and anti-solvents were screened using Hansen Solubility Parameter Theory for PS, ABS, and ESR dissolution. The pre-screening results showed dichloromethane (DCM) and tetrahydrofuran (THF) as the most effective solvents for PS and ABS, with methanol (MeOH) and ethylene glycol (EG) as the most effective anti-solvents. By optimizing the dissolution time and the solvents used, the highest polymer dissolution yield (99 wt.%) was achieved using DCM for 48 h. Both MeOH and EG precipitated 71 wt.% of the polymer fraction of ESR. EG removed more phosphorus containing flame retardants (94 wt.%) than MeOH (69 wt.%). Energy analysis indicated that the solvent-based processes could save 25–60% of the embodied energy for PS and ABS. Characterization showed that the solvent-based processing could preserve the high molecular weight fraction of the polymers while removing flame retardants at the same time. The results from this study prove the potential of solvent-based processing to produce secondary plastic materials from E-waste for cross-industry reuse.

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RASIDGAZI, HARUN AL, HEMANT K. KASHYAP und RANJIT BISWAS. „Solvent sorting in (mixed solvent + electrolyte) systems: Time-resolved fluorescence measurements and theory“. Journal of Chemical Sciences 127, Nr. 1 (Januar 2015): 61–70. http://dx.doi.org/10.1007/s12039-014-0750-5.

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van Leuken, Stijn H. M., Rolf A. T. M. van Benthem, Remco Tuinier und Mark Vis. „Theoretically predicting the solubility of polydisperse polymers using Flory–Huggins theory“. Journal of Physics: Materials 7, Nr. 1 (16.11.2023): 015005. http://dx.doi.org/10.1088/2515-7639/ad08d1.

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Abstract Polydispersity affects physical properties of polymeric materials, such as solubility in solvents. Most biobased, synthetic, recycled, mixed, copolymerized, and self-assembled polymers vary in size and chemical structure. Using solvent fractionation, this variety in molecular features can be reduced and a selection of the sizes and molecular features of the polymers can be made. The significant chemical and physical dispersity of these polymers, however, complicates theoretical solubility predictions. A theoretical description of the fractionation process can guide experiments and material design. During solvent fractioning of polymers, a part of the polydisperse distribution of the polymers dissolves. To describe this process, this paper presents a theoretical tool using Flory–Huggins theory combined with molecular mass distributions and distributions in the number of functional groups. This paper quantifies how chemical and physical polydispersity of polymers affects their solubility. Comparison of theoretical predictions with experimental measurements of lignin in a mixture of solvents shows that multiple molecular features can be described well using a single set of parameters, giving a tool to theoretically predict the selective solubility of polymers.

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Shulgin, Ivan L., und Eli Ruckenstein. „A protein molecule in an aqueous mixed solvent: Fluctuation theory outlook“. Journal of Chemical Physics 123, Nr. 5 (August 2005): 054909. http://dx.doi.org/10.1063/1.2011388.

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Roy, Nath, Lovely Sarkar und Kumar Sarkar. „Study of solute-solvent interactions of nicotinic acid and benzoic acid in methanol and its binary solvent systems“. Journal of the Serbian Chemical Society 73, Nr. 12 (2008): 1235–46. http://dx.doi.org/10.2298/jsc0812235r.

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The apparent molar volumes, ?V, and viscosity B-coefficients, B, for nicotinic acid (NA) and benzoic acid (BA) in mixed solvents containing 10, 20, 30 mass % of n-amyl alcohol (n-AmOH) or isoamyl alcohol (i-AmOH) in methanol and in pure methanol (MeOH) were determined from the solution density and viscosity measurements at 298.15 K as function of concentrations of NA and BA. These results were, in conjunction with the results obtained in pure methanol, used to deduce the partial molar volumes of transfer, 0 ??V , and viscosity B-coefficients of transfer, ?B, for NA and BA from methanol to different mixed methanol solvents, in order to rationalize various interactions in the ternary solutions. An increase in the transfer properties of NA and BA with increasing mass % of n-AmOH and i-AmOH in methanol was observed and explained by the effect of structural changes and preferential solvation. Also, the free energies of viscous flow, ? 0? 1 ? and ? 0? ?2 , per mole of solvent and solute, respectively, were calculated and analyzed on the basis of the transition state theory of relative viscosity.

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Wang, Jiayuan, Lingyu Zhu und Richard Lakerveld. „A Hybrid Framework for Simultaneous Process and Solvent Optimization of Continuous Anti-Solvent Crystallization with Distillation for Solvent Recycling“. Processes 8, Nr. 1 (02.01.2020): 63. http://dx.doi.org/10.3390/pr8010063.

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Anti-solvent crystallization is frequently applied in pharmaceutical processes for the separation and purification of intermediate compounds and active ingredients. The selection of optimal solvent types is important to improve the economic performance and sustainability of the process, but is challenged by the discrete nature and large number of possible solvent combinations and the inherent relations between solvent selection and optimal process design. A computational framework is presented for the simultaneous solvent selection and optimization for a continuous process involving crystallization and distillation for recycling of the anti-solvent. The method is based on the perturbed-chain statistical associated fluid theory (PC-SAFT) equation of state to predict relevant thermodynamic properties of mixtures within the process. Alternative process configurations were represented by a superstructure. Due to the high nonlinearity of the thermodynamic models and rigorous models for distillation, the resulting mixed-integer nonlinear programming (MINLP) problem is difficult to solve by state-of-the-art solvers. Therefore, a continuous mapping method was adopted to relax the integer variables related to solvent selection, which makes the scale of the problem formulation independent of the number of solvents under consideration. Furthermore, a genetic algorithm was used to optimize the integer variables related to the superstructure. The hybrid stochastic and deterministic optimization framework converts the original MINLP problem into a nonlinear programming (NLP) problem, which is computationally more tractable. The successful application of the proposed method was demonstrated by a case study on the continuous anti-solvent crystallization of paracetamol.

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Matteoli, Enrico. „Analysis of the enthalpy of solvation in mixed solvents using the Kirkwood-Buff theory. The interplay of preferential solvation and solvent-solvent interactions“. Journal of Molecular Liquids 79, Nr. 2 (Februar 1999): 101–21. http://dx.doi.org/10.1016/s0167-7322(98)00106-8.

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Martinez-Fernandez, Lara, Thomas Gustavsson, Ulf Diederichsen und Roberto Improta. „Excited State Dynamics of 8-Vinyldeoxyguanosine in Aqueous Solution Studied by Time-Resolved Fluorescence Spectroscopy and Quantum Mechanical Calculations“. Molecules 25, Nr. 4 (13.02.2020): 824. http://dx.doi.org/10.3390/molecules25040824.

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The fluorescent base guanine analog, 8-vinyl-deoxyguanosine (8vdG), is studied in solution using a combination of optical spectroscopies, notably femtosecond fluorescence upconversion and quantum chemical calculations, based on time-dependent density functional theory (TD-DFT) and including solvent effect by using a mixed discrete-continuum model. In all investigated solvents, the fluorescence is very long lived (3–4 ns), emanating from a stable excited state minimum with pronounced intramolecular charge-transfer character. The main non-radiative decay channel features a sizeable energy barrier and it is affected by the polarity and the H-bonding properties of the solvent. Calculations provide a picture of dynamical solvation effects fully consistent with the experimental results and show that the photophysical properties of 8vdG are modulated by the orientation of the vinyl group with respect to the purine ring, which in turn depends on the solvent. These findings may have importance for the understanding of the fluorescence properties of 8vdG when incorporated in a DNA helix.

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Arshad, Mahwish, Nasir Rasool, Muhammad Usman Qamar, Syed Adnan Ali Shah und Zainul Amiruddin Zakaria. „Facile Synthesis of Functionalized Phenoxy Quinolines: Antibacterial Activities against ESBL Producing Escherichia coli and MRSA, Docking Studies, and Structural Features Determination through Computational Approach“. Molecules 27, Nr. 12 (10.06.2022): 3732. http://dx.doi.org/10.3390/molecules27123732.

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The synthesis of new 6-Bromoquinolin-4-ol derivatives (3a–3h) by Chan–Lam coupling utilizing different types of solvents (protic, aprotic, and mixed solvents) and bases was studied in the present manuscript. Furthermore, their potential against ESBL producing Escherichia coli (ESBL E. coli) and methicillin-resistant Staphylococcusaureus (MRSA) were investigated. Commercially available 6-bromoquinolin-4-ol (3a) was reacted with different types of aryl boronic acids along with Cu(OAc)2 via Chan–Lam coupling methodology utilizing the protic and aprotic and mixed solvents. The molecules (3a–3h) exhibited very good yields with methanol, moderate yields with DMF, and low yields with ethanol solvents, while the mixed solvent CH3OH/H2O (8:1) gave more excellent results as compared to the other solvents. The in vitro antiseptic values against ESBL E. coli and MRSA were calculated at five different deliberations (10, 20, 30, 40, 50 mg/well) by agar well diffusion method. The molecule 3e depicted highest antibacterial activity while compounds 3b and 3d showed low antibacterial activity. Additionally, MIC and MBC standards were calculated against the established bacteria by broth dilution method. Furthermore, a molecular docking investigation of the derivatives (3a–3h) were performed. Compound (3e) was highly active and depicted the least binding energy of −5.4. Moreover, to investigate the essential structural and physical properties, the density functional theory (DFT) findings of the synthesized molecules were accomplished by using the basic set PBE0-D3BJ/def2-TZVP/SMD water level of the theory. The synthesized compounds showed an energy gap from 4.93 to 5.07 eV.

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Maheshwari, R. K., Apeksha Apte und Om Prakash Agrawal. „Spectrophotometric analysis of tablets of nalidixic acid using melted niacinamide as solvent“. Journal of Drug Delivery and Therapeutics 9, Nr. 1-s (15.02.2019): 206–8. http://dx.doi.org/10.22270/jddt.v9i1-s.2323.

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In the current attempt of research, novel method for spectrophotometric estimation of nalidixic acid in tablets using melted niacinamide as solvent was developed. The main objective behind research is to show “SOLIDS ALSO POSSESS SOLUBILIZING POWER”. The current study deals with novel spectrophotometric analytical technique for quantitative estimation of nalidixic acid in tablets using melted niacinamide as solvent. According to the theory proposed by Maheshwari, each & every substance possesses solubilising power; substance may be a gas, solid or liquid. Niacinamide imbibes large solubilizing power to nalidixic acid and having approximate solubility more than 80 mg per gm of melted niacinamide (135°C) whereas aqueous solubility of nalidixic acid is 0.21mg/ml at room temperature. Calibration curve of nalidixic acid was plotted by recording the absorbances of standard solutions of drug. The absorbances were observed at 330 nm against respective reagent blanks. The percentage label claims were found very close to 100 (100.93± 1.303 and 99.08±1.764) indicating accuracy of the proposed method. Percentage recoveries estimated by the proposed method are close to 100 (99.91±1.303 and 101.74±1.663) with significant low values of percentage deviation and standard error. Thus, it may be concluded that proposed method is simple, safe and precise and excludes use of toxic organic solvents. Keywords: Mixed Solvency, Solubilizing Power, Spectrophotometric Analysis, Niacinamide, Nalidixic Acid.

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Birshtein, T. M., und Yu V. Lyatskaya. „Theory of the Collapse-Stretching Transition of a Polymer Brush in a Mixed Solvent“. Macromolecules 27, Nr. 5 (September 1994): 1256–66. http://dx.doi.org/10.1021/ma00083a028.

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Jiang, Jin-gang, Zhao Wang, Hong-wei Duan, Jing-qiang Liu und Xiao-wei Guo. „Electric Field Simulation and Effect of Different Solvent Ratios on the Performance of Single Electrospun PVDF/PEI Composite Film“. Advances in Materials Science and Engineering 2016 (2016): 1–8. http://dx.doi.org/10.1155/2016/4329283.

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On the basis of the finite element calculation theory of electric field, the electric field distribution in a representative electrospinning device is computed. The electric field structure of a needle-plate type electrospinning device was simulated by means of ANSYS software. And the vector distribution of the nozzle on the spinneret pipe was got. For the purpose of the analysis on the influence of different solvent ratios on the performance of a single electrospun PVDF/PEI composite film, polyvinylidene fluoride and polyetherimide with a mass ratio of 8/2 were dissolved in a mixed solvent. The mixed solvent is composed of N,N-dimethylformamide and tetrahydrofuran, added in different proportions. Through the electrostatic spinning technology, PVDF/PEI composite fiber membranes were prepared. Using scanning electron microscopy (SEM), X-ray diffraction (XRD), differential scanning calorimetry (DSC), and mechanical properties testing, the effects of tetrahydrofuran on the composite microstructure, crystallinity, and mechanical properties of the PVDF/PEI composite fiber membranes are discussed.

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Patra, Chandra N. „Size and charge correlations in spherical electric double layers: a case study with fully asymmetric mixed electrolytes within the solvent primitive model“. RSC Advances 10, Nr. 64 (2020): 39017–25. http://dx.doi.org/10.1039/d0ra06145j.

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Yigit, Ekrem Akif, und Yahya Erkan Akansu. „Investigation of Deep Eutectic Solvent Based Super Dielectric Electrolytes for Supercapacitors“. Energy Environment and Storage 3, Nr. 3 (30.09.2023): 119–25. http://dx.doi.org/10.52924/mskh9311.

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This study investigates a new type of electrolyte based on deep eutectic solvents. Choline chloride based deep eutectic solvents were prepared and they were used as base ionic solvents for super dielectric theory. Deep eutectic solvent was mixed with a non-conducting material such as fumed silica, alumina. The mixture shows a super dielectric behavior which is used as electrolyte for electrochemical double layer capacitors also known as supercapacitors. The supercapacitor cells were composed of an electrode, a paper-based separator and this super dielectric electrolyte. The electrode of commercial standard supercapacitor is used first as an electrode. Second an electrode slurry was prepared in order to make custom electrode. Then the performance of both cells was investigated. The specific capacitances of cells were measured and the amount of increase at the capacitances was evaluated. The results showed that up to 14-fold increase of the specific capacitances of the commercial supercapacitor have been achieved. Also, up to 12-fold increase of the specific capacitances of our custom-made cells have been achieved. The charge-discharge characteristics and ESR values of the cells confirms that the cells show outperforming properties. Deep eutectic solvents based super dielectric electrolytes are very promising electrolytes for high energy density supercapacitors.

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Lee, Lloyd L. „A molecular theory of Setchenov's salting-out principle and applications in mixed-solvent electrolyte solutions“. Fluid Phase Equilibria 131, Nr. 1-2 (Mai 1997): 67–82. http://dx.doi.org/10.1016/s0378-3812(96)03198-6.

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Lee, L. L., L. J. Lee, D. Ghonasgi, M. Llano-Restrepo, W. G. Chapman, K. P. Shukla und E. Lomba. „Theory and simulation for electrolyte solutions: applications to the phase equilibria of mixed solvent systems“. Fluid Phase Equilibria 116, Nr. 1-2 (März 1996): 185–92. http://dx.doi.org/10.1016/0378-3812(95)02886-2.

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ZHONG, JING, ZHI-GANG CHEN, JUN-MIN LIAO, MING-SHIUAN TANG, CHENG-BIN CHEN und CHENG-LUNG CHEN. „STUDY ON HOMOGENEOUS PRECIPITATION OF CeO2 NANOPARTICLES BY DISSIPATIVE PARTICLE DYNAMICS SIMULATION“. Journal of Theoretical and Computational Chemistry 08, Nr. 03 (Juni 2009): 459–73. http://dx.doi.org/10.1142/s021963360900485x.

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Dissipative particle dynamics (DPD) was carried out to study the nucleation and crystal growth process of cerium dioxide ( CeO 2) nanoparticles in alcohol/water mixed solvents by homogeneous precipitation method. The results showed that properly selecting the sizes of CeO 2 and water beads, and choosing the appropriate interaction parameters between beads are crucial in the simulation system. The nucleation and crystal growth process of CeO 2 can be classified into four stages: induction, nuclei growth, crystal forming, and crystal aggregation, which could be reproduced from different initial CeO 2 concentration and after different simulation time. The simulation results confirm that the effect of solvent on the nucleation and crystal growth of CeO 2 nanoparticles are different at four stages and cannot be simply described by Derjaguin–Landau–Verwey–Overbeek theory or nucleation thermodynamics theory as proposed in the published literatures. Our work demonstrated that DPD methods can be applied to study nanoparticle forming process.

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Shulgin, Ivan L., und Eli Ruckenstein. „A Protein Molecule in a Mixed Solvent: The Preferential Binding Parameter via the Kirkwood-Buff Theory“. Biophysical Journal 90, Nr. 2 (Januar 2006): 704–7. http://dx.doi.org/10.1529/biophysj.105.074112.

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Wu, Rong-Song, und Lloyd L. Lee. „Vapor-liquid equilibria of mixed-solvent electrolyte solutions: ion-size effects based on the MSA theory“. Fluid Phase Equilibria 78 (Oktober 1992): 1–24. http://dx.doi.org/10.1016/0378-3812(92)87026-j.

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Neumaier, Lisa, Johannes Schilling, André Bardow und Joachim Gross. „Dielectric constant of mixed solvents based on perturbation theory“. Fluid Phase Equilibria 555 (April 2022): 113346. http://dx.doi.org/10.1016/j.fluid.2021.113346.

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Smith, Paul E., und Robert M. Mazo. „On the Theory of Solute Solubility in Mixed Solvents“. Journal of Physical Chemistry B 112, Nr. 26 (Juli 2008): 7875–84. http://dx.doi.org/10.1021/jp712179w.

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Yoshimori, Akira, Tyler J. F. Day und G. N. Patey. „Theory of ion solvation dynamics in mixed dipolar solvents“. Journal of Chemical Physics 109, Nr. 8 (22.08.1998): 3222–31. http://dx.doi.org/10.1063/1.476912.

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Senior, Samir A., und Ahmed M. Nassar. „Determination of pK a for substituted benzoic acids in mixed solvent using density functional theory and QSPR“. International Journal of Quantum Chemistry 112, Nr. 3 (08.03.2011): 683–94. http://dx.doi.org/10.1002/qua.23048.

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Monni, Roberto, Gloria Capano, Gerald Auböck, Harry B. Gray, Antonín Vlček, Ivano Tavernelli und Majed Chergui. „Vibrational coherence transfer in the ultrafast intersystem crossing of a diplatinum complex in solution“. Proceedings of the National Academy of Sciences 115, Nr. 28 (25.06.2018): E6396—E6403. http://dx.doi.org/10.1073/pnas.1719899115.

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We investigate the ultrafast transient absorption response of tetrakis(μ-pyrophosphito)diplatinate(II), [Pt2(μ-P2O5H2)4]4− [hereafter abbreviated Pt(pop)], in acetonitrile upon excitation of its lowest singlet 1A2u state. Compared with previously reported solvents [van der Veen RM, Cannizzo A, van Mourik F, Vlček A, Jr, Chergui M (2011) J Am Chem Soc 133:305–315], a significant shortening of the intersystem crossing (ISC) time (<1 ps) from the lowest singlet to the lowest triplet state is found, allowing for a transfer of vibrational coherence, observed in the course of an ISC in a polyatomic molecule in solution. Density functional theory (DFT) quantum mechanical/molecular mechanical (QM/MM) simulations of Pt(pop) in acetonitrile and ethanol show that high-lying, mostly triplet, states are strongly mixed and shifted to lower energies due to interactions with the solvent, providing an intermediate state (or manifold of states) for the ISC. This suggests that the larger the solvation energies of the intermediate state(s), the shorter the ISC time. Because the latter is smaller than the pure dephasing time of the vibrational wave packet, coherence is conserved during the spin transition. These results underscore the crucial role of the solvent in directing pathways of intramolecular energy flow.

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Nagarajan, R., und Chien-Chung Wang. „Theory of Surfactant Aggregation in Water/Ethylene Glycol Mixed Solvents“. Langmuir 16, Nr. 12 (Juni 2000): 5242–51. http://dx.doi.org/10.1021/la9910780.

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Nikitas, Panaghiotis, und Adriani Pappa-Louisi. „Adsorption isotherms for coadsorption studies from solution“. Canadian Journal of Chemistry 64, Nr. 2 (01.02.1986): 328–32. http://dx.doi.org/10.1139/v86-055.

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The mixed adsorption of k adsorbates from solution on energetically homogeneous surfaces is studied by means of lattice statistical thermodynamics. The adsorption layer is considered to behave as a non-electrolyte bulk solution composed from k adsorbates and solvent. On the basis of this assumption the adsorption isotherms and their state equations are determined by means of the lattice theory of strictly regular solutions and Flory–Huggins statistics. The thermodynamic restrictions imposed when these models have to be applied to real systems are also determined and discussed.

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Slyusarenko, K., V. Reshetnyak und Yu Reznikov. „Magnetic field control of the ordering of two-component suspension of hard rods“. Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 371, Nr. 1988 (13.04.2013): 20120250. http://dx.doi.org/10.1098/rsta.2012.0250.

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The Onsager theory of hard rod dispersion in a neutral solvent is extended to a case of two-component dispersion consisting of both non-magnetic and magnetic rods. It was found that the alignment of magneto-sensitive dispersion component by a magnetic field leads to the alignment of non-magnetic component in the dispersion and to an elimination of the isotropic phase. This effect is significant even at low relative concentrations of magnetic rods and leads to a magnetically induced anisotropy in a non-magnetic dispersion of rods mixed with the magnetic ones.

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Ali, A., S. Khan und F. Nabi. „Volumetric, viscometric and refractive index behavior of amino acids in aqueous glycerol at different temperatures“. Journal of the Serbian Chemical Society 72, Nr. 5 (2007): 495–512. http://dx.doi.org/10.2298/jsc0705495a.

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Densities, ?, viscosities, ? and refractive indices, n D, of solutions of some amino acids (glycine, DL-alanine, DL-? -amino- n-butyric acid, L-valine and L-leucine) in the concentration range 0.02 to 0.10 m in 5 % (v/v) aqueous glycerol were determined at 298.15, 303.15, 308.15 and 313.15 K. These experimental data were used to calculate the apparent molar volumes, ? v, the infinite dilution apparent molar volumes, ? v 0, the partial molar volumes of transfer, ? v 0 (tr), of the amino acids from aqueous to aqueous glycerol solution, as well as the viscosity A and B coefficients of the Jones-Dole equation of the amino acids. The free energies of activation of viscous flow, ??1 0# and ?? 2 0# per mole of solvent and solute, respectively, were obtained by application of the transition-state theory to the B coefficient data and the corresponding activation enthalpy, ?H*, and entropy, ?S*, were also determined. The ? v 0, B coefficients and ?? 2 0# were found to vary linearly with increasing number of carbon atoms in the alkyl chain of the amino acids, and they were split into contributions from the zwitterionic end groups (NH3 +, COO-) and methylene (CH2) groups of the amino acids. The experimental values of the refractive indices, n D, were used to calculate the molar refractive indices, R D, of the amino acids + aqueous glycerol ternary mixtures. The results were interpreted in the light of the solute-solvent and solute-solute interactions in the mixed solvents.

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Das, Bijan. „A Study on the Preferential Solvation of Ions in Mixed Aqueous Binary Solvent Systems Using the Scaled Particle Theory“. Bulletin of the Chemical Society of Japan 67, Nr. 5 (Mai 1994): 1217–20. http://dx.doi.org/10.1246/bcsj.67.1217.

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Soria, Vicente, Juan E. Figueruelo, Concepción Abad und Agustín Campos. „Association Equilibria Theory for Polymers in Mixed Solvents with Specific Interactions“. Macromolecular Theory and Simulations 13, Nr. 5 (03.06.2004): 441–52. http://dx.doi.org/10.1002/mats.200300047.

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34

Wang, Zhangxia, und Haibo Ma. „Mechanisms of a Cyclobutane-Fused Lactone Hydrolysis in Alkaline and Acidic Conditions“. Molecules 26, Nr. 12 (09.06.2021): 3519. http://dx.doi.org/10.3390/molecules26123519.

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Searching for functional polyesters with stability and degradability is important due to their potential applications in biomedical supplies, biomass fuel, and environmental protection. Recently, a cyclobutane-fused lactone (CBL) polymer was experimentally found to have superior stability and controllable degradability through hydrolysis reactions after activation by mechanical force. In order to provide a theoretical basis for developing new functional degradable polyesters, in this work, we performed a detailed quantum chemical study of the alkaline and acidic hydrolysis of CBL using dispersion-corrected density functional theory (DFT-D3) and mixed implicit/explicit solvent models. Various possible hydrolysis mechanisms were found: BAC2 and BAL2 in the alkaline condition and AAC2, AAL2, and AAL1 in the acidic condition. Our calculations indicated that CBL favors the BAC2 and AAC2 mechanisms in alkaline and acidic conditions, respectively. In addition, we found that incorporating explicit water solvent molecules is highly necessary because of their strong hydrogen-bonding with reactant/intermediate/product molecules.

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Lone, Mohsin Yousuf, und Prakash Chandra Jha. „Quantum Chemical Study of Mixed-Ligand Monometallic Ruthenium(II) Complex of Composition [(bpy)2Ru(H3Imbzim)](ClO4)2·2H2O“. Journal of Quantum Chemistry 2014 (19.05.2014): 1–8. http://dx.doi.org/10.1155/2014/149380.

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On the basis of density functional theoretical approach, we have assessed the ground state geometries and absorption spectra of recently synthesized monometallic ruthenium (II) complex of composition [(bpy)2Ru(H3Imbzim)](ClO4)2·2H2O where bpy = 2,2′-bypyridine and H3Imbzim = 4,5-bis(benzimidazol-2-yl)imidazole. The all different kinds of charge transfers such as ligand-ligand, and metal-ligand have been quantified, compared, and contrasted with the experimental results. In addition, the effect of solvent on excitation energies has been evaluated. In spite of some digital discrepancies in calculated and observed geometries, as well as in absorption spectra, the density functional theory (DFT) seems to explain the main features of this complex.

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Guha, Prabir K., und Kiron K. Kundu. „Free energies and entropies of transfer of hydrogen halides from water to aqueous 2-methoxy ethanol and structuredness of the solvents“. Canadian Journal of Chemistry 63, Nr. 4 (01.04.1985): 798–803. http://dx.doi.org/10.1139/v85-132.

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Standard free energies (ΔGt0) and entropies (ΔSt0) of transfer of HBr and HI from water to some aqueous solutions of 2-methoxy ethanol (ME) have been determined from emf measurements of the cells: Pt, H2 (g, 1 atm)/HBr (m), solvent/AgBr–Ag and Pt, H2 (g, 1 atm)/KOH (m1), KI (m2), solvent/AgI–Ag, respectively, at seven equidistant temperatures ranging from 15 to 45 °C. ΔGt0 values of HBr and HI as well as of HCl obtained from literature, and particularly that of the individual ions obtained by tetraphenylarsonium tetraphenylboron (TATB) assumption, suggest that while H+ is increasingly stabilized by cosolvent-induced larger "basicity", halide ions (X−) are increasingly destabilized by cosolvent-induced decreased "acidity" and the dielectric constant of the mixed solvents compared to that of water. Analysis of the variation of the observed TΔSt0(HX) and particularly of ΔY (= TΔSt0(H+) + TΔS0t.ch (X−), with composition, in the light of Kundu etal's semi-quantitative theory reveals that ME induces breakdown of three dimensional (3D) tetrahedral structures of water at water-rich compositions. This is being followed by an ordered region due to possible H-bonded cosolvent–water complexation and then the usual disordered region due to packing imbalance. Comparison of ΔY(HI)–composition profiles for aqueous mixtures of t-butanol (ButOH), ethylene glycol (EG), and 1,2-dimethoxy ethane (DME) also demonstrates that the remarkable enhancement of 3D water structures by the well known structure promoter ButOH gets succintly diminished when cosolvent ButOH is replaced by EG, ME, and DME, as is expected from structural and electronic considerations of the cosolvents.

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Dadras, Abbas, Ali Benvidi, Mansoor Namazian, Saleheh Abbasi, Dehghan Tezerjani, Moharram Roozegari und Reza Tabaraki. „Determination of the pKa for caffeic acid in mixed solvent using the net analyte signal method and ab initio theory“. Journal of the Serbian Chemical Society 84, Nr. 4 (2019): 391–403. http://dx.doi.org/10.2298/jsc180614116d.

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Due to the biological effects of phenolic acid components, polyphenol-rich foods are a significant part of human and animal diets. In this study, the acidity constants of caffeic acid (3,4-dihydroxycinnamic acid) in binary mixtures of ethanol?water were determined spectrophotometrically using the introduced net analyte signal (NAS) algorithm and an ab initio quantum mechanical method. The NAS is an efficient chemometric algorithm for analysis of acid?base equilibrium systems by a spectrophotometric method. At different pH values, the distribution of acid species is obtained from an absorption data matrix and this procedure enabled the pKa of caffeic acid to be obtained alternatively. The results showed that pKa1 (4.02, 4.26, 4.39, 4.57 and 5.11) and pKa2 (8.43, 8.68, 8.79, 9.00 and 9.34) were increased by increasing the percent ethanol in water (0, 10, 20, 30 and 40 vol. %) and these results were in agreement with the results of the Gaussian method. The ab initio calculated Gibbs energy change showed that para-hydroxy group is more acidic than meta-hydroxy group. The red shifts of different species of caffeic acid obtained using the ab initio quantum mechanical method are in good agreement with the results of UV?Vis spectroscopy.

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Kebede, Tamiru, Mulualem Abebe, Dhakshnamoorthy Mani, Aparna Thankappan, Sabu Thomas und Jung Yong Kim. „Silver-Doped CsPbI2Br Perovskite Semiconductor Thin Films“. Electronic Materials 5, Nr. 2 (13.05.2024): 56–70. http://dx.doi.org/10.3390/electronicmat5020005.

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All-inorganic perovskite semiconductors have received significant interest for their potential stability over heat and humidity. However, the typical CsPbI3 displays phase instability despite its desirable bandgap of ~1.73 eV. Herein, we studied the mixed halide perovskite CsPbI2Br by varying the silver doping concentration. For this purpose, we examined its bandgap tunability as a function of the silver doping by using density functional theory. Then, we studied the effect of silver on the structural and optical properties of CsPbI2Br. Resultantly, we found that ‘silver doping’ allowed for partial bandgap tunability from 1.91 eV to 2.05 eV, increasing the photoluminescence (PL) lifetime from 0.990 ns to 1.187 ns, and, finally, contributing to the structural stability when examining the aging effect via X-ray diffraction. Then, through the analysis of the intermolecular interactions based on the solubility parameter, we explain the solvent engineering process in relation to the solvent trapping phenomena in CsPbI2Br thin films. However, silver doping may induce a defect morphology (e.g., a pinhole) during the formation of the thin films.

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Srour, Rafif K., und Louis M. McDonald. „Solution Properties of Inorganic Contamination in Mixed Solvents: Theory, Progress, and Limitations“. Critical Reviews in Environmental Science and Technology 41, Nr. 6 (07.02.2011): 521–621. http://dx.doi.org/10.1080/10643380902945839.

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Rezaei Behbehani, G., und W. E. Waghorne. „A high-performance theory for thermodynamic study of solvation in mixed solvents“. Thermochimica Acta 478, Nr. 1-2 (November 2008): 1–5. http://dx.doi.org/10.1016/j.tca.2008.08.014.

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41

Negadi, Amina, Anne Sans-Pennincks, Mustapha Benmouna und Thomas A. Vilgis. „Mean-field-theory for polymers in mixed solvents. Thermodynamic and structural properties“. Macromolecular Theory and Simulations 8, Nr. 4 (01.07.1999): 285–95. http://dx.doi.org/10.1002/(sici)1521-3919(19990701)8:4<285::aid-mats285>3.0.co;2-w.

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Sato, Kunihiko, Shun Saito, Satoshi Yanase und Takao Oi. „Estimation of Reduced Partition Function Ratios of Lithium-Graphite Intercalation Compounds by Density Functional Theory“. Zeitschrift für Naturforschung A 69, Nr. 3-4 (01.04.2014): 122–28. http://dx.doi.org/10.5560/zna.2013-0085.

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The reduced partition function ratio (RPFR) of lithium in lithium-graphite intercalation compounds (Li-GICs) was evaluated at the UB3LYP=6-311G(d) level of theory. The partition functions were written in the usual rigid-rotor harmonic oscillator approximation.With a C24H12 coronene molecule as the model of graphene, lithium-coronene sandwich, and club sandwich compounds were considered as models of Li-GICs. The estimated value of the 6Li-to-7Li RPFR was 1.0402 at 25 °C, which yielded 1.034 as the value of the equilibrium constant, K, of the lithium isotope exchange reaction between a lithium ion in an ethylene carbonate=ethylmethyl carbonate mixed solvent and a lithium atom in interlayer space of graphite. The estimated value of K was larger than the experimental value of 1.025. The unsatisfactory agreement between the estimated and experimental K values suggested that larger molecules should be used as models of graphene and that the vibrational anharmonicity should also be taken into consideration.

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Golmohammadi, Farhad, Masoud Amiri, Hussein Gharibi, Ali Yousefi und Meysam Safari. „Co-solvent Effect on Spontaneous Formation of Large Nanoscale Structures in Catanionic Mixtures in the Anionic-Rich Region“. Journal of Solution Chemistry 49, Nr. 1 (28.11.2019): 16–33. http://dx.doi.org/10.1007/s10953-019-00935-6.

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AbstractThe aggregation behavior was investigated in mixtures of sodium dodecyl sulfate (SDS) and cetyltrimethylammonium bromide (CTAB) (anionic-rich catanionic) solutions. The study was conducted in solutions of water–ethylene glycol (EG) by means of surface tension, conductometry, cyclic voltammetry, zeta potential measurements, transmission electron microscopy (TEM) and dynamic light scattering (DLS) techniques. The degree of counterion dissociation (α), critical micelle concentration, aggregation numbers, interfacial properties, interparticle interaction parameters, and morphology of aggregates were determined. Based on regular solution theory, the cosolvent effects between SDS and CTAB as surfactants were also analyzed for both mixed monolayers at mixed micelles (βM) and the air/liquid interface (βσ). It was shown that the formation of large aggregates occurred in the presence of an excess of anionic surfactant. A phase transition from cylindrical micelles to spherical micelles in the anionic-rich regime was observed with an increase in the EG volume fraction. The inter particle interactions were assessed in terms of cosolvent effects on the micellar surface charge density and the cylindrical-to-spherical morphology change. Zeta potential and size of the aggregates were determined using dynamic light scattering and confirmed the models suggested for the processes taking place in each system.

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Simoni, Luke D., Joan F. Brennecke und Mark A. Stadtherr. „Asymmetric Framework for Predicting Liquid−Liquid Equilibrium of Ionic Liquid−Mixed-Solvent Systems. 1. Theory, Phase Stability Analysis, and Parameter Estimation“. Industrial & Engineering Chemistry Research 48, Nr. 15 (05.08.2009): 7246–56. http://dx.doi.org/10.1021/ie900461j.

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DZWINEL, WITOLD, und DAVID A. YUEN. „A TWO-LEVEL, DISCRETE PARTICLE APPROACH FOR LARGE-SCALE SIMULATION OF COLLOIDAL AGGREGATES“. International Journal of Modern Physics C 11, Nr. 05 (Juli 2000): 1037–61. http://dx.doi.org/10.1142/s0129183100000882.

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Most numerical techniques employed for aggregation simulation are based on equilibrium growth assumption and Smoluchowski theory. We present a new two-level discrete particle model, which can be employed in simulating large colloidal clusters in highly nonequilibrium physical conditions. We consider the system of colloidal particles (CP) interacting via conservative CP–CP repulsive-attractive two-body forces, which is initially mixed in a dissipative solvent. In order to obtain a high-resolution picture of colloidal dynamics, we employ around 20 million particles consisting of two kinds of particles. For bridging the spatio-temporal scales between nanoscale colloidal and the solvent particles (SP), the solvent is modeled by dissipative particle dynamics (DPD) fluid. We focus on the systems size for which the CP–SP interactions can also be described by the DPD forces. Unlike previous numerical techniques, the two-level particle model can display much more realistic physics, thus allowing for the simulation of aggregation for various types of colloids and solvent liquids in a broad range of conditions. We show that not only large and static clusters but also the initial stages of aggregation evolution can be better scrutinized. The large-scale simulation results obtained in two-dimensions show that the mean cluster size grows with time t according to the power law tκ. Because of the time-dependence of growth mechanism, the value of κ necessarily must change. We have first κ = 1 with a value of 1 achieved asymptotically with time. We can also discern intermediate-scale structures. We emphasize that the method developed here can be easily extended to algorithms dealing with multi-level hierarchy and multiphase fluid dynamics.

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Snigur, D. V., A. N. Chebotarev, T. M. Shcherbakova, E. M. Rakhlytskaya und V. V. Shapovalenko. „IONIZATION OF ETHANOLAMINES IN WATER- ORGANIC MEDIA“. Odesa National University Herald. Chemistry 28, Nr. 1(84) (10.05.2023): 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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Lee, Jia Lin, Gun Hean Chong, Asami Kanno, Masaki Ota, Haixin Guo und Richard Lee Smith. „Local composition-regular solution theory for analysis of pharmaceutical solubility in mixed-solvents“. Journal of Molecular Liquids 397 (März 2024): 124012. http://dx.doi.org/10.1016/j.molliq.2024.124012.

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48

Singh, R. P., und Dhirendra Singh. „Effect of Cosolvent (Acetone) on the Adsorption and Movement of Cypermethrin in Indian Soils“. Adsorption Science & Technology 15, Nr. 2 (Januar 1997): 135–45. http://dx.doi.org/10.1177/026361749701500207.

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The adsorption and movement of cypermethrin in different types of uncontaminated soils in acetone-water mixtures at different fs values has been studied by batch shake and soil thin-layer chromatographic techniques, respectively. Higher adsorption and a reduced movement of cypermethrin was observed on silt clay loam soil followed by loam and sandy loam soils and was anticipated by the Freundlich adsorption constants Km and Rf values. The Km and Rf values also confirmed that the adsorption of cypermethrin decreased while its movement increased with increasing fs values. The values of the Freundlich constant Km were used to evaluate the cosolvent theory for describing the adsorption of cypermethrin in acetone–water mixtures. For each soil, the values of the adsorption coefficient Km decreased in a linear logarithmic fashion as fs increased, the slopes of the log Km versus fs plots being essentially the same for all soils. Thus, the cosolvent effects on adsorption could be expressed by a single parameter (σs) which combines the characteristics of the solvent (acetone) and the adsorbate (cypermethrin). For adsorbates with a low solubility in aqueous solutions, the adsorption data from mixed solvents was extrapolated to fs = 0 to estimate the values of the adsorption constant Kw in the aqueous phase.

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Yang, Yanqing, Anna Krin, Xiaoli Cai, Mohammad Reza Poopari, Yuefei Zhang, James R. Cheeseman und Yunjie Xu. „Conformations of Steroid Hormones: Infrared and Vibrational Circular Dichroism Spectroscopy“. Molecules 28, Nr. 2 (12.01.2023): 771. http://dx.doi.org/10.3390/molecules28020771.

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Steroid hormone molecules may exhibit very different functionalities based on the associated functional groups and their 3D arrangements in space, i.e., absolute configurations and conformations. Infrared (IR) and vibrational circular dichroism (VCD) spectra of four different steroid hormones, namely dehydroepiandrosterone (DHEA), 17α-methyltestosterone (MTTT), (16α,17)-epoxyprogesterone (Epoxy-P4), and dehydroepiandrosterone acetate (AcO-DHEA), were measured in deuterated dimethyl sulfoxide and some also in carbon tetrachloride. Extensive conformational searches were carried out using the recent developed conformer-rotamer ensemble sampling tool (CREST) which also accounts for solvent effects using an implicit solvation model. All the CREST conformational candidates were then reoptimized at the B3LYP-D3BJ/def2-TZVPD with the PCM of solvent. The good agreements between the experimental IR and VCD spectra and the theoretical simulations provide a conclusive information about their conformational distribution and absolute configurations. The experimental and theoretical IR and VCD spectra of AcO-DHEA in the carbonyl and alkene stretching region showed some discrepancies, and the possible causes related to solvent effects, large amplitude motions and levels of theory used in the modelling were explored in detail. As part of the investigation, additional calculations at the B3LYP-D3BJ/6-31++G (2d,p) and B3LYP-D3BJ/cc-pVTZ levels, as well as some ‘mixed’ calculations with the double-hybrid functional B2PLYP-D3 were also carried out. The results indicate that the double-hybrid functional is important for predicting the correct IR band pattern in the carbonyl and alkene stretching region.

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Solntsev, Pavlo V., Ben D. Neisen, Jared R. Sabin, Nikolay N. Gerasimchuk und Victor N. Nemykin. „Synthesis, characterization, X-ray structure, and mixed-valence states of trans-dichlorotin(IV)-5,10,15,20-tetraferrocenylporphyrin“. Journal of Porphyrins and Phthalocyanines 15, Nr. 07n08 (Juli 2011): 612–21. http://dx.doi.org/10.1142/s1088424611003537.

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Reaction between H2TFcP (TFcP2- is a dianion of 5,10,15,20-tetraferrocenylporphyrin) with tin(II) chloride results in formation of the trans- Cl2SnTFcP complex, which was characterized by UV-vis, MCD, 1H and 13C NMR, and APCI MS methods. X-ray single crystal analysis was used to determine the structure of the target compound. Crystallography reveals a very unusual α,α,β,β-conformation of the ferrocene groups and largely planar structure of the porphyrin macrocycle. Density functional theory calculations predict that the HOMO in trans- Cl2SnTFcP is predominantly ferrocene centered, while LUMO is primarily localized over the porphyrin core. Redox properties of the trans- Cl2SnTFcP complex were investigated using electrochemical (CV and DPV), spectroelectrochemical, and chemical oxidation approaches. Electrochemical experiments conducted in low-polarity solvent using non-coordinating electrolyte reveal the sequential oxidation of ferrocene substituents along with porphyrin-based single-electron oxidation and reduction processes. The first ferrocene oxidation process is separated by 130 mV from the next three ferrocene based oxidations, which are more closely spaced. Mixed-valence [trans- Cl2SnTFcP]+ was generated in situ by spectroelectrochemical and chemical oxidation approaches and characterized by UV-vis-NIR spectroscopy.

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