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Artículos de revistas sobre el tema "Nonpolar solvents"

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Publicado: 18 de mayo de 2024

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1

Roy, J. L. y W. B. McGill. "Flexible conformation in organic matter coatings: An hypothesis about soil water repellency". Canadian Journal of Soil Science 80, n.º 1 (1 de febrero de 2000): 143–52. http://dx.doi.org/10.4141/s98-093.

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Some soils develop severe water repellency several years or decades following oil contamination. We previously reported that soil water repellency is completely eliminated by extraction with amphiphilic solvents, but barely reduced by extraction with nonpolar solvents. We report here on solvent-induced reversible soil water repellency. Our results indicate that: (i) water repellency is completely eliminated following extraction with amphiphilic solvent, but partially restored following subsequent exposure to nonpolar, non-H-bonding solvent; (ii) extraction with nonpolar, non-H-bonding solvent generates water repellency in readily wettable control wettable soils, but not in pristine wettable soils, and (iii) repeated sequential extractions alternating between amphiphilic and nonpolar, non-H-bonding solvent increase extractable material and reduce the magnitude of solvent-induced soil water repellency with time.We attribute reversible soil water repellency to solvent-induced changes in the conformation of causative agents of soil water repellency. Recent literature reports on the structural flexibility of "insoluble" organic macromolecules are discussed for supporting evidence. We propose that exposure to nonpolar, non-H-bonding solvents induces stretching of surface-exposed, nonpolar moieties (i.e. alkyl chains), whereas exposure to polar, H-bonding solvents induces their coiling. These solvent-induced conformational changes are retained upon solvent removal. Our results indicate that the wettability of oil-contaminated soils depends on both the interfacial conformation and the fractional coverage of their surface-exposed nonpolar moieties. Key words: Soil water repellency, crude oil, hydrophobic soil, conformational flexibility, swelling, solvents

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2

Saita, Satoshi, Shin-ichi Takeda y Hideya Kawasaki. "Hansen Solubility Parameter Analysis on Dispersion of Oleylamine-Capped Silver Nanoinks and their Sintered Film Morphology". Nanomaterials 12, n.º 12 (10 de junio de 2022): 2004. http://dx.doi.org/10.3390/nano12122004.

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Optimizing stabilizers and solvents is crucial for obtaining highly dispersed nanoparticle inks. Generally, nonpolar (hydrophobic) ligand-stabilized nanoparticles show superior dispersibility in nonpolar solvents, whereas polar ligand (hydrophilic)-stabilized nanoparticles exhibit high dispersibility in polar solvents. However, these properties are too qualitative to select optimum stabilizers and solvents for stable nanoparticle inks, and researchers often rely on their experiences. This study presents a Hansen solubility parameter (HSP)-based analysis of the dispersibility of oleylamine-capped silver nanoparticle (OAm-Ag NP) inks for optimizing ink preparation. We determined the HSP sphere of the OAm-Ag NPs, defined as the center coordinate, and the interaction radius in 3D HSP space. The solvent’s HSP inside the HSP sphere causes high dispersibility of the OAm-Ag NPs in the solvent. In contrast, the HSPs outside the sphere resulted in low dispersibility in the solvent. Thus, we can quantitatively predict the dispersibility of the OAm-Ag NPs in a given solvent using the HSP approach. Moreover, the HSP sphere method can establish a correlation between the dispersibility of the particles in inks and the sintered film morphology, facilitating electronic application of the nanoparticle inks. The HSP method is also helpful for optimizing stabilizers and solvents for stable nanoparticle inks in printed electronics.

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3

Pytela, Oldřich. "A new classification of solvents based on chemometric empirical scale of parameters". Collection of Czechoslovak Chemical Communications 55, n.º 3 (1990): 644–52. http://dx.doi.org/10.1135/cccc19900644.

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The paper presents a classification of 51 solvents based on clustering in three-dimensional space formed by the empirical scale of PAC, PBC, and PPC parameters designed for interpretation of solvent effect on a model with cross-terms. For the classification used are the clustering methods of the nearest neighbour, of the furthest neighbour, of average bond, and the centroid method. As a result, the solvents have been divided into 8 classes denoted as: I - nonpolar-inert solvents (aliphatic hydrocarbons), IIp - nonpolar-polarizable (aromatic hydrocarbons, tetrachloromethane, carbon disulphide), IIb - nonpolar-basic (ethers, triethylamine), IIIp - little polar-polarizable (aliphatic halogen derivatives, substituted benzenes with heteroatom-containing substituents), IIIb - little polar-basic (cyclic ethers, ketones, esters, pyridine), IVa - polar-aprotic (acetanhydride, dialkylamides, acetonitrile, nitromethane, dimethyl sulfoxide, sulfolane), IVp - polar-protic (alcohols, acetic acid), and V - exceptional solvents (water, formamide, glycol, hexamethylphosphoric triamide). The information content of the individual parameters used for the classification has been determined. The classification is based primarily on solvent polarity/acidity (PAC), less on polarity/basicity (PBC), and the least on polarity/polarizability (PPC). Causal relation between chemical structure of solvent and its effect on the process taking place therein has been established.

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4

Suljkanović, Mersiha, Jasmin Suljagić, Edita Bjelić, Ante Prkić y Perica Bošković. "Chemical Characterization of Terpene-Based Hydrophobic Eutectic Solvents and Their Application for Pb(II) Complexation during Solvent Extraction Procedure". Molecules 29, n.º 9 (3 de mayo de 2024): 2122. http://dx.doi.org/10.3390/molecules29092122.

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Solvents prepared from natural terpenes (menthol and thymol), as H-bond acceptors, and a series of organic acids (chain lengths of 8, 10, and 14 C atoms), as H-bond donors, were characterized and tested as reaction media for liquid–liquid extraction purposes. Due to their high hydrophobicity, they seem to be promising alternatives to conventional (nonpolar and toxic) solvents, since they possess relatively less toxic, less volatile, and consequently, more environmentally friendly characteristics. Assuming that the equilibrium is established between solvent and analyte during a ligandless procedure, it can be concluded that those nonpolar solvents can efficiently extract nonpolar analytes from the aqueous environment. Previous investigations showed a wide range of applications, including their use as solvents in extractions of metal cations, small molecules, and bioactive compounds for food and pharmaceutical applications. In this work, hydrophobic solvents based on natural terpenes, which showed chemical stability and desirable physicochemical and thermal properties, were chosen as potential reaction media in the liquid–liquid extraction (LLE) procedure for Pb(II) removal from aqueous solutions. Low viscosities and high hydrophobicities of prepared solvents were confirmed as desirable properties for their application. Extraction parameters were optimized, and chosen solvents were applied. The results showed satisfactory extraction efficiencies in simple and fast procedures, followed by low solvent consumption. The best results (98%) were obtained by the thymol-based solvent, thymol–decanoic acid (Thy-DecA) 1:1, followed by L-menthol-based solvents: menthol–octanoic acid (Men-OctA) 1:1 with 97% and menthol–decanoic acid (Men-DecA) 1:1 with 94.3% efficiency.

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5

Al Mohaimeed, Rawabi M., Anees A. Ansari y Abdullah Aldwayyan. "The Role of Solvent Environment on the Optical Behavior of Chemically Synthesized Silicon Nanoparticles". Journal of Spectroscopy 2018 (2018): 1–9. http://dx.doi.org/10.1155/2018/6870645.

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Silicon nanoparticles (Si-NPs) were prepared by solution-based chemical etching method. Optical characteristics of the as-prepared Si-NPs were investigated in different polar and nonpolar organic solvents. The emission and absorption properties of Si-NPs were tuned by altering the environment (solvents). The variation in absorption coefficient was observed because of the solvent interaction nature of Si-NPs. Si-NPs in polar aprotic and nonpolar solvents manifested good luminescence under UV excitation. PL intensities were observed to be depending on etched cross-section area on wafer surface. The results show a linear dependence of the refractive index (n) on wavelength (λ). The nature of solvents altered the luminescence efficiency of Si-NPs when examining under UV lamp. The emission and absorption properties of Si-NPs were tuned by altering the environment (solvents) through electrostatic interaction of various organic solvents with the Si-NPs. The band shapes of the Si-NPs show remarkable changes in passing from noncoordinating solvent (chloroform) to various coordinating solvents, which was the result of change in the environment around Si-NPs in various solutions.

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6

Ghosh, Rajib, Amitabha Nandi y Dipak K. Palit. "Solvent sensitive intramolecular charge transfer dynamics in the excited states of 4-N,N-dimethylamino-4′-nitrobiphenyl". Physical Chemistry Chemical Physics 18, n.º 11 (2016): 7661–71. http://dx.doi.org/10.1039/c5cp07778h.

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Solvent sensitive excited state dynamics of DNBP is explored. In polar solvents, the ultrafast barrierless TICT process is the major relaxation pathway, whereas, in nonpolar solvents the excited state undergoes the PICT process, followed by efficient intersystem crossing to the triplet state.

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7

Werst, D. W. "Solvent effects in nonpolar solvents: Radical anion reactions". Chemical Physics Letters 202, n.º 1-2 (1993): 101–7. http://dx.doi.org/10.1016/0009-2614(93)85357-t.

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8

Wu, Xiaoli, Xulin Cui, Qi Wang, Jingtao Wang, Wenjia Wu, Wenpeng Li y Zhongyi Jiang. "Manipulating the cross-layer channels in g-C3N4 nanosheet membranes for enhanced molecular transport". Journal of Materials Chemistry A 9, n.º 7 (2021): 4193–202. http://dx.doi.org/10.1039/d0ta10236a.

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Cross-layer channels display ‘gate effect’ to govern molecular selectivity for lamellar membranes. Membranes with hydrophilic/hydrophobic heterostructured channels acquire elevated polar solvent permeance and polar/nonpolar solvents selectivity.

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9

Kovalenko, G. A. y L. V. Perminova. "Heterogeneous Biocatalytic Processes of the Low-Temperature Synthesis of Esters: Selection of Organic Solvent". Kataliz v promyshlennosti 20, n.º 4 (20 de julio de 2020): 313–22. http://dx.doi.org/10.18412/1816-0387-2020-4-313-322.

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Processes of the low-temperature enzymatic synthesis of esters in nonaqueous media of organic solvents with participation of heterogeneous biocatalysts synthesized by the adsorption immobilization of a recombinant lipase from Thermomyces lanuginosus (Pichia pastoris producer) on macroporous carbon aerogel were investigated. The esterification reaction was conducted using individual organic solvents of different polarity, such as nonpolar ones (lоgP > 2.5) – hexadecane, hexane and toluene, and polar solvents (lоgP < 1) – diethyl ether, tert-butanol and acetone, as well as their binary mixtures of different composition, for example, a mixture of hexane with diethyl ether having the composition 1 : (1/5÷3, vol. fr.). The effect of the solvent and co-solvent nature on the properties of synthesized biocatalysts, namely the enzymatic activity and operational stability, was studied in the batch esterification of heptanoic acid (C7:0) by alcohols, particularly the polar substrates – ethanol and n-butanol, or nonpolar alcohols – n-octanol and n-hexadecanol. Activity of the synthesized biocatalysts was found to depend to a great extent on polarity of both the solvents used in the reaction and the alcohol substrates. The maximum activity of 400 EA·g–1 was observed in a medium of nonpolar and nonviscous hexane (lоgP = 2.9), whereas the minimum activity of 4 EA·g–1 – in acetone (lоgP = 0.4); esterification of heptanoic acid in the presence of tert-butanol (lоgP = 0.6) virtually did not proceed. The activity of biocatalysts was shown to depend nonmonotonically on the lоgP value of individual solvent. In the binary mixtures of organic solvents, such as hexane/diethyl ether, biocatalytic activity linearly increased with an increase in lоgPmixture; in addition, biocatalysts exhibited the maximum operational stability.

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10

Siplivy, Nickolay y Anatoly Ivanov. "Features of the Electronic Structure of Excited Quadrupolar Molecules in Non-Polar Solvents". Mathematical Physics and Computer Simulation, n.º 2 (julio de 2021): 68–84. http://dx.doi.org/10.15688/mpcm.jvolsu.2021.2.6.

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Interactions of the electronic subsystem of the quadrupolar fluorophore with intramolecular highfrequency antisymmetric vibrations and solvent polarization are responsible for charge transfer symmetry breaking (SB), which is observed after optical excitation of such molecules in polar solvents. It is known that although these two interactions are mathematically described in similar ways, only the interaction of the fluorophore with solvent orientational polarization can create a state with broken symmetry if this interaction is strong enough. Nevertheless, the interaction of a quadrupolar fluorophore with intramolecular highfrequency antisymmetric vibrations in nonpolar solvents leads to a considerable reconstruction of the electronic subsystem. The analysis of the excited state of quadrupolar molecules in nonpolar solvents performed in this study reveals that such molecules can behave like quantum twostate systems, that is, as a quasispin s = 1/2, having an electric dipole moment instead of a magnetic one. This feature of excited quadrupolar molecules may be of interest to emerging technologies of molecular electronics.

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11

Chen, Gang, Mingzhu Xia, Wu Lei, Fengyun Wang y Xuedong Gong. "Molecular dynamics investigation of the effect of solvent adsorption on crystal habits of hexogen". Canadian Journal of Chemistry 92, n.º 9 (septiembre de 2014): 849–54. http://dx.doi.org/10.1139/cjc-2014-0243.

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In this work, a molecular dynamics investigation was performed to study the effect of the solvents acetone and cyclohexanone on the crystal habits of hexogen. The results show that the adsorption energies of hexogen polar faces such as the (002), (210), (111), and (200) faces are larger than that of the nonpolar (020) face. The adsorption interactions of hexogen surfaces with acetone are stronger than those with cyclohexanone. The adsorption interactions consist of van der Waals and electrostatic interactions. The effect of solvents on the crystal growth of hexogen is discussed by comparing the adsorption energy of each crystal face. It may qualitatively predict that if hexogen crystallizes from polar solvents (acetone and cyclohexanone), the morphological importance of polar faces increases, especially in acetone solvent, while the importance of the nonpolar (020) face probably diminishes, even disappears. The theoretical prediction properly explains the different crystal morphologies of hexogen observed experimentally in these two solvents.

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12

Nevěčná, Taťjana, Vojtěch Bekárek y Oldřich Pytela. "A Study of Effects of Temperature and Medium on Reaction of Triethylamine with Ethyl Bromide". Collection of Czechoslovak Chemical Communications 59, n.º 6 (1994): 1384–91. http://dx.doi.org/10.1135/cccc19941384.

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The rate constants of reaction of triethylamine with ethyl bromide have been measured in 13 solvents at the temperatures of 293, 313, 333, and 373 K. The activation entropies in the individual solvents increase when going from nonpolar to dipolar aprotic and polar protic solvents, which is explained by dominant solvation of the basic triethylamine and by formation of highly ordered associates without solvent in the activated complex in nonpolar solvent media. No isokinetic relationship has been found between the activation entropy and activation enthalpy, which indicates different solvent effects on the two quantities. The activation enthalpy and entropy of the reaction investigated are close to those of the reaction of triethylamine with ethyl iodide. Three methods have been used to evaluate the effect of medium at all the temperatures, their success being decreased in the order: Pytela's method - Kamlet-Taft - Koppel-Palm. Irrespective of the temperature, all the methods indicate that the reaction is accelerated by the solvent polarity, the significance of other effects being reflected differently depending on the temperature and the correlation equation used. A complex evaluation involving also the interpretation of the entropy and enthalpy components by means of empiric solvent parameters has shown that the resulting Gibbs energy represents a superposition of different effects of solvents on the two thermodynamic quantities, the solvent effect upon the activation entropy being predominant at the higher temperatures.

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13

Hsu, M. F., E. R. Dufresne y D. A. Weitz. "Charge Stabilization in Nonpolar Solvents". Langmuir 21, n.º 11 (mayo de 2005): 4881–87. http://dx.doi.org/10.1021/la046751m.

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14

YOGESHRI J. JIBHKATE, ABHIJIT P. AWACHAT, R.T. LOHIYA, MILIND J UMEKAR, ATUL T. HEMKE y KRISHNA R. GUPTA. "Extraction: An important tool in the pharmaceutical field". International Journal of Science and Research Archive 10, n.º 1 (30 de septiembre de 2023): 555–68. http://dx.doi.org/10.30574/ijsra.2023.10.1.0768.

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The present review discuss various extraction methods used in obtaining bioactive compounds from medicinal plants. It defines key terms like "medicinal plant," "menstruum," and "marc." The choice of solvent (menstruum) depends on plant type and bioactive compounds. Polar solvents (e.g., water) are used for polar compounds, while nonpolar solvents (e.g., hexane) are used for nonpolar compounds. Solvents are categorized by polarity from least polar (n-hexane) to most polar (water). Different extraction methods are detailed, including infusion, decoction, percolation, maceration, Soxhlet extraction, supercritical fluid extraction, microwave-assisted extraction, and ultrasound-assisted extraction. The advantages and disadvantages of each method are discussed. The abstract covers the properties and applications of different solvents, such as water, alcohol, chloroform, ether, and ionic liquids. Factors like selectivity, safety, cost, reactivity, and recovery are important in selecting solvents. The abstract concludes by discussing the advantages and disadvantages of different extraction methods, including hydro distillation. It emphasizes the importance of choosing the right method based on the nature of the plant material and desired compounds.

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15

Graziano, Giuseppe. "Size dependence of the solubility of nonpolar compounds in different solvents". Canadian Journal of Chemistry 80, n.º 4 (1 de abril de 2002): 401–12. http://dx.doi.org/10.1139/v02-040.

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At 25°C, plots of the standard Gibbs energy change associated with the solvation of noble gases and aliphatic hydrocarbons vs. the size of the solutes prove to be approximately linear with a negative slope for common organic solvents but not for water. In the latter case, the plot has a characteristic V-shape. The slope is negative for noble gases, methane, and ethane, but is positive for larger alkanes. This means that the solubility of nonpolar solutes increases with solute size in every solvent except water. The solvation thermodynamics of noble gases and aliphatic hydrocarbons in five solvents (water, ethanol, benzene, c-hexane, and n-hexane) are analyzed in detail by a general theory, which is rederived to avoid risky misunderstandings. The calculations are performed in the same manner for all solvents, using simple formulas where the physical reliability is well established and the results are consistent. The work of cavity creation increases with solute size in every solvent, but to a far greater extent in water. Additionally, the work to turn on the solutesolvent attractive interactions increases in magnitude with solute size in every solvent, but to a lesser extent in water. By combining these two factors a satisfactory explanation for experimental data obtained emerges. The microscopic origins of the difference between water and common organic solvents are discussed.Key words: solvation, excluded-volume effect, solutesolvent interactions, enthalpyentropy compensation, molecular size.

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16

Bekárek, Vojtěch, Jan Jílek y Antonín Haviger. "Effect of Medium on the Electronic Spectra of 2-Nitroaniline Derivatives". Collection of Czechoslovak Chemical Communications 61, n.º 1 (1996): 155–59. http://dx.doi.org/10.1135/cccc19960155.

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The wavenumbers of the long-wavelength absorption band were measured for nine 4-substituted and 5-substituted derivatives of 2-nitroaniline in the gaseous state and in 13 solvents where only nonspecific solvent-solute interactions can be expected. For the series involving all the solvents used, the solvent effects can be well expressed by an one-parameter equation involving the product of the Born functions of the relative permittivity and of the refractive index of the solvent. For the series involving the nonpolar solvents and the gaseous state only, this equation reduces to an one-parameter equation involving the refractive index Born function squared.

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17

Tant, Martin R., Garth L. Wilkes y Joseph P. Kennedy. "Sulfonated polyisobutylene telechelic ionomers. XIII. Viscosity behavior in nonpolar solvents and nonpolar–polar solvent mixtures". Journal of Applied Polymer Science 37, n.º 10 (20 de mayo de 1989): 2873–95. http://dx.doi.org/10.1002/app.1989.070371008.

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18

Aniceto, José P. S., Bruno Zêzere y Carlos M. Silva. "Predictive Models for the Binary Diffusion Coefficient at Infinite Dilution in Polar and Nonpolar Fluids". Materials 14, n.º 3 (23 de enero de 2021): 542. http://dx.doi.org/10.3390/ma14030542.

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Experimental diffusivities are scarcely available, though their knowledge is essential to model rate-controlled processes. In this work various machine learning models to estimate diffusivities in polar and nonpolar solvents (except water and supercritical CO2) were developed. Such models were trained on a database of 90 polar systems (1431 points) and 154 nonpolar systems (1129 points) with data on 20 properties. Five machine learning algorithms were evaluated: multilinear regression, k-nearest neighbors, decision tree, and two ensemble methods (random forest and gradient boosted). For both polar and nonpolar data, the best results were found using the gradient boosted algorithm. The model for polar systems contains 6 variables/parameters (temperature, solvent viscosity, solute molar mass, solute critical pressure, solvent molar mass, and solvent Lennard-Jones energy constant) and showed an average deviation (AARD) of 5.07%. The nonpolar model requires five variables/parameters (the same of polar systems except the Lennard-Jones constant) and presents AARD = 5.86%. These results were compared with four classic models, including the 2-parameter correlation of Magalhães et al. (AARD = 5.19/6.19% for polar/nonpolar) and the predictive Wilke-Chang equation (AARD = 40.92/29.19%). Nonetheless Magalhães et al. requires two parameters per system that must be previously fitted to data. The developed models are coded and provided as command line program.

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19

Ahmed, Asmaa N. "A study of the solvent effect on the low temperature spectra of benzoanthracene molecules". Iraqi Journal of Physics (IJP) 12, n.º 24 (17 de febrero de 2019): 1–9. http://dx.doi.org/10.30723/ijp.v12i24.315.

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been taken at room temperature down to liquid nitrogen temperature (77K). Polar and nonpolar solvents have been used to study the solvent effect on the absorption and fluorescence spectra of solute molecules. Some of the spectroscopic parameters have been determined as functions of solvent polarity and temperature. The results indicate that the band width FWHM increases with increasing the solvent polarity and temperature, while the peak emission cross section decreases with increasing of solvent polarity and decreases with increasing the temperatures. Clear vibrational structure spectra of benzoanthracene molecules have been observed in Nonane and Hexane solvents at 77K.

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20

Wang, Yan-zhen, Hai-long Xu, Li Gao, Meng-meng Yan, Hong-ling Duan y Chun-min Song. "Regeneration of Spent Lubricant Refining Clays by Solvent Extraction". International Journal of Chemical Engineering 2015 (2015): 1–7. http://dx.doi.org/10.1155/2015/207095.

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Step-by-step solvent extraction was used to regenerate spent clay by recovering the adsorbed oil in lubricating oil refining clay. Several polar and nonpolar solvents were tested, and petroleum ether (90–120°C) and ethanol (95 v%) were selected as the nonpolar and polar solvents, respectively. The spent clay was first extracted using petroleum ether (90–120°C) to obtain ideal oil and then extracted with a mixed solvent of petroleum ether (90–120°C) and ethanol (95 v%) two or three times to obtain nonideal oil before being extracted with ethanol and water. Finally, the clay was dried at 130°C to obtain regenerated clay. The total oil recovery can be more than 99 wt% of the adsorbed oil. The recovered ideal oil can be used as lubricating base oil. Shorter storage times for spent clay produce better regeneration results. The regenerated clay can be reused to refine the lubricating base oils.

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21

Bekárek, Vojtěch. "A comment on evaluation of effects of mixed solvents by means of the Born and Kirkwood method". Collection of Czechoslovak Chemical Communications 54, n.º 12 (1989): 3162–70. http://dx.doi.org/10.1135/cccc19893162.

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The evaluation of the mixed solvent effect by means of the Kirkwood and Born functions of the relative permitivity of the mixed solvent has been criticized as a thermodynamically inconsistent procedure. A procedure has been suggested to estimate the composition of solvation sphere around dipolar molecules or transition states in binary mixtures of a polar and a nonpolar solvents.

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22

Yang, Dapeng, Min Jia, Jingyuan Wu, Xiaoyan Song y Qiaoli Zhang. "An analogy study on ESIPT reaction for 3BHC sensor between polar DMF and nonpolar toluene". Canadian Journal of Chemistry 95, n.º 12 (diciembre de 2017): 1303–7. http://dx.doi.org/10.1139/cjc-2017-0463.

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A comparison about excited state intramolecular proton transfer (ESIPT) mechanism of a new sensor 3-(1,3-benzothiazol-2-yl)-2-hydroxynaphthalene-1-carbaldehyde (3BHC) in polar solvent dimethylformamide (DMF) and nonpolar solvent toluene have been investigated within the framework of the time-dependent density functional theory (TD-DFT) method. The reproduced previous experimental absorption and emission spectra via our calculations reveals the reasonability of the DFT and TD-DFT theoretical level. The staple bond lengths, bond angles, and corresponding infrared vibrational spectra demonstrate that the intramolecular hydrogen bond of 3BHC should be strengthened in both polar DMF and nonpolar toluene. Two kinds of ESIPT mechanisms for different solvents have been put forward; there is a low potential barrier in the ESIPT process in the DMF solvent, whereas there is almost a nonbarrier for the ESIPT process in the toluene solvent. Hence, we could conclude that the ESIPT process of 3BHC sensor is more likely to occur in the nonpolar solvent upon the photoexcitation, based on which, the excited state behavior of 3BHC could be controlled.

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23

Yang, Fulin, Shuangjie Zhang, Tanxiao Shen, Juechen Ni, Jie Zhang, Xiao Cheng, Jing Zhi Sun, Zhisheng Fu y Ben Zhong Tang. "Polymerization of 1-chloro-2-phenylacetylene derivatives by using a Brookhart-type catalyst". Polymer Chemistry 10, n.º 35 (2019): 4801–9. http://dx.doi.org/10.1039/c9py00974d.

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A Brookhart-type catalyst (α-diimine)PdMeCl/AgOTf works well in the polymerization of 1-chloro-2-phenylacetylene monomers bearing nonpolar/polar and electron releasing/withdrawing substituents in nonpolar/polar solvents.

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Fuchs, Richard, Eric J. Chambers y W. Kirk Stephenson. "Enthalpies of interaction of nonpolar solutes with nonpolar solvents. The role of solute polarizability and molar volume in solvation". Canadian Journal of Chemistry 65, n.º 11 (1 de noviembre de 1987): 2624–27. http://dx.doi.org/10.1139/v87-433.

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Heats of solution of 10 nonpolar solutes (carbon tetrachloride, perfluoroheptane, diiodomethane, benzene, hexane, decane, hexadecane, cyclohexane, toluene, and mesitylene) in 11 nonpolar solvents (heptane, cyclohexane, carbon tetrachloride, benzene, carbon disulfide, diiodomethane, toluene, mesitylene, tetrachloroethylene, 1,1,2-trichlorotrifluoroethane, and hexadecane) have been combined with solute heats of vaporization to give enthalpies of transfer from vapor to solvent (ΔH(v → S)). The heat of vaporization of diiodomethane has been measured (11.70 ± 0.01 kcal/mol). Correlations of the form ΔH(v → S) = a + bMMR + cMV describe the solvent–solute interaction enthalpies with high precision (correlation coefficients 0.991–0.999). Earlier correlations with only the molar refraction are limited to solutes of similar refractive index. In each solvent ΔH(v → S) becomes more exothermic with an increase in the solute molar refraction term, and less exothermic with an increase in the solute molar volume term. These terms represent solvent–solute dispersion interaction enthalpies, and solvent cavity formation enthalpies, respectively.

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Zhang, Yimeng, Pengyao Xing, Minmin Yang, Yajie Wang, Bo Wang, Aiyou Hao y Mingfang Ma. "Solvent-polarity-tuned nanostructures assembled from modified octadecylcarbamate with an anthracen moiety". RSC Advances 6, n.º 76 (2016): 71963–69. http://dx.doi.org/10.1039/c6ra14563a.

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26

Farrokhbin, Mojtaba, Biljana Stojimirović, Marco Galli, Mohsen Khajeh Aminian, Yannick Hallez y Gregor Trefalt. "Surfactant mediated particle aggregation in nonpolar solvents". Physical Chemistry Chemical Physics 21, n.º 35 (2019): 18866–76. http://dx.doi.org/10.1039/c9cp01985e.

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27

Holroyd, Richard A. "Electron attachment to C60 in nonpolar solvents". Radiation Physics and Chemistry 72, n.º 2-3 (febrero de 2005): 79–84. http://dx.doi.org/10.1016/j.radphyschem.2004.09.002.

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28

Yablon, Dalia G. y Alan M. Schilowitz. "Solvatochromism of Nile Red in Nonpolar Solvents". Applied Spectroscopy 58, n.º 7 (julio de 2004): 843–47. http://dx.doi.org/10.1366/0003702041389328.

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29

Aleksandrovа, Е. А., B. L. Aleksandrov, Zh T. Khadisova, Kh Kh Akhmadova y L. Sh Makhmudova. "Crystallization and Structural Solidification of Paraffins in Various Solvents". Chemistry and Technology of Fuels and Oils 624, n.º 2 (2021): 25–29. http://dx.doi.org/10.32935/0023-1169-2021-624-2-25-29.

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The temperatures of the beginning of crystallization and solidification of solutions of petroleum and synthetic paraffins of different concentrations in nonpolar and weakly polar hydrocarbon solvents of different composition and viscosity are studied. It is shown that paraffins of different origin and hydrocarbon composition, with similar melting points, have slightly different crystallization temperatures аnd solidification in this solvent. The temperature range between the temperatures of the beginning of crystallization and solidification of the studied paraffin solutions is established.

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30

Xu, Zhuang, Mengli Li, Guowang Shen, Yuhao Chen, Dashun Lu, Peng Ren, Hao Jiang, Xugen Wang y Bin Dai. "Solvent Effects in the Preparation of Catalysts Using Activated Carbon as a Carrier". Nanomaterials 13, n.º 3 (18 de enero de 2023): 393. http://dx.doi.org/10.3390/nano13030393.

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The role of solvents is crucial in catalyst preparation. With regard to catalysts prepared with activated carbon (AC) as the carrier, when water is used as a solvent it is difficult for the solution to infiltrate the AC. Because AC comprises a large number of C atoms and is a nonpolar material, it is more effective for the adsorption of nonpolar substances. Since the water and active ingredients are polar, they cannot easily infiltrate AC. In this study, the dispersion of the active component was significantly improved by optimizing the solvent, and the particle size of the active component was reduced from 33.08 nm to 15.30 nm. The specific surface area of the catalyst is significantly increased, by 10%, reaching 991.49 m2/g. Under the same reaction conditions, the conversion of acetic acid by the catalyst prepared with the mixed solvent was maintained at approximately 65%, which was 22% higher than that obtained using the catalyst prepared with water as the solvent.

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31

Lamothe, S., K. L. Cook y T. H. Chan. "Chiral organosilicon compounds in synthesis. Preparation and stereoselective alkylations of silylcinnamyl carbanions". Canadian Journal of Chemistry 70, n.º 6 (1 de junio de 1992): 1733–42. http://dx.doi.org/10.1139/v92-217.

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Silylallyl carbanions of type 13 bearing a chiral lithium complexing substituent remote from silicon can be alkylated regio- and stereoselectively at the α-position by small electrophiles in nonpolar solvents. The regiochemical outcome of the reaction was found to be highly dependent on the size of the incoming electrophile. Secondary alkyl halides react preferentially at the γ-center and good levels of stereoselectivity are still obtained in nonpolar solvents despite the rather long distance between the reacting center and the chiral auxiliary. Transformation of the alkylated allylsilanes into optically active alcohols and carboxylic acids may represent a potential synthetic application of the method.

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32

Guerdouh, Amel y Djamel Barkat. "Experimental study of the extraction of chromium (III) from nitrate medium by lauric acid". Metallurgical and Materials Engineering 24, n.º 3 (19 de octubre de 2018): 189–97. http://dx.doi.org/10.30544/385.

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The solvent extraction of chromium (III) with lauric acid (HL) at 25°C is studied as a function of various parameters: pH of the aqueous phase, the concentration of lauric acid and the nature of the solvent. The solvent effects on the extraction of chromium (III) using polar and nonpolar solvents has been observed. It was shown that extracted species of the [Cr(OH)L2·2HL] formula are formed in cyclohexane, dichloromethane, chloroform, and toluene. However, in 1- -octanol or methyl isobutyl ketone, it was found a complex of the type [Cr(OH)L2]. The extraction constants and extraction yield (%E) are also calculated for different solvents. It was found that cyclohexane is the preferred solvent for this extraction system, The maximum extraction yield is accomplished using the cyclohexane as a solvent on 1:1 L/L ratio, and pH value of 4.73.

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33

Tikhonov, D. A. y G. N. Sarkisov. "Local structure of solvation of nonpolar chains in nonpolar solvents at infinite dilution". Journal of Structural Chemistry 37, n.º 4 (julio de 1996): 639–44. http://dx.doi.org/10.1007/bf02437178.

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34

Arivalagan, Premkumar Rathinam y Yan Zhao. "Interfacial catalysis of aldol reactions by prolinamide surfactants in reverse micelles". Organic & Biomolecular Chemistry 13, n.º 3 (2015): 770–75. http://dx.doi.org/10.1039/c4ob02074j.

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35

Smith, Gregory N., James E. Hallett y Julian Eastoe. "CelebratingSoft Matter's 10th Anniversary: Influencing the charge of poly(methyl methacrylate) latexes in nonpolar solvents". Soft Matter 11, n.º 41 (2015): 8029–41. http://dx.doi.org/10.1039/c5sm01190f.

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36

Wildervanck, Martijn J., Reinhard Hecht y Agnieszka Nowak-Król. "Synthesis and Strong Solvatochromism of Push-Pull Thienylthiazole Boron Complexes". Molecules 27, n.º 17 (27 de agosto de 2022): 5510. http://dx.doi.org/10.3390/molecules27175510.

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The solvatochromic behavior of two donor-π bridge-acceptor (D-π-A) compounds based on the 2-(3-boryl-2-thienyl)thiazole π-linker and indandione acceptor moiety are investigated. DFT/TD-DFT calculations were performed in combination with steady-state absorption and emission measurements, along with electrochemical studies, to elucidate the effect of two different strongly electron-donating hydrazonyl units on the solvatochromic and fluorescence behavior of these compounds. The Lippert–Mataga equation was used to estimate the change in dipole moments (Δµ) between ground and excited states based on the measured spectroscopic properties in solvents of varying polarity with the data being supported by theoretical studies. The two asymmetrical D-π-A molecules feature strong solvatochromic shifts in fluorescence of up to ~4300 cm−1 and a concomitant change of the emission color from yellow to red. These changes were accompanied by an increase in Stokes shift to reach values as large as ~5700–5800 cm−1. Quantum yields of ca. 0.75 could be observed for the N,N-dimethylhydrazonyl derivative in nonpolar solvents, which gradually decreased along with increasing solvent polarity, as opposed to the consistently reduced values obtained for the N,N-diphenylhydrazonyl derivative of up to ca. 0.20 in nonpolar solvents. These two push–pull molecules are contrasted with a structurally similar acceptor-π bridge-acceptor (A-π-A) compound.

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37

Wu, Minghong, Jing Zhan, Bijiang Geng, Piaopiao He, Kuan Wu, Liang Wang, Gang Xu, Zhen Li, Luqiao Yin y Dengyu Pan. "Scalable synthesis of organic-soluble carbon quantum dots: superior optical properties in solvents, solids, and LEDs". Nanoscale 9, n.º 35 (2017): 13195–202. http://dx.doi.org/10.1039/c7nr04718e.

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38

Cho, Dae Won y Dae Won Cho. "Excimer and exciplex emissions of 1,8-naphthalimides caused by aggregation in extremely polar or nonpolar solvents". New J. Chem. 38, n.º 6 (2014): 2233–36. http://dx.doi.org/10.1039/c3nj01473h.

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39

Kapoor, Utkarsh y Jindal K. Shah. "Effect of molecular solvents of varying polarity on the self-assembly of 1-n-dodecyl-3-methylimidazolium octylsulfate ionic liquid". Journal of Theoretical and Computational Chemistry 17, n.º 03 (mayo de 2018): 1840004. http://dx.doi.org/10.1142/s0219633618400047.

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Large-scale molecular dynamics simulations consisting of more than 88,000–106,000 atoms for approximately 250 ns (including equilibration and production) were conducted to assess the effect of polar, nonpolar and amphiphilic molecular solvents on the nanoscale structuring of 1-[Formula: see text]-dodecyl-3-methylimidazolium [C[Formula: see text]mim] octylsulfate [C8SO4] ionic liquid (IL). Water [H2O], [Formula: see text]-octane [C8H[Formula: see text]] and 1-octanol [C8H[Formula: see text]OH] are employed as examples of polar, nonpolar, and amphiphilic molecules, respectively. The results indicate that each of these molecular solvents modify the nanosegregation behavior of the ionic liquid in a unique way. Water induces a high order of structuring of the ionic liquid as indicated by extremely high nematic order parameter for the system. In addition, the morphology of the neat ionic liquid is transformed from layer-like to that of bilayer-like in which the polar and nonpolar domains alternate. The presence of water also causes the stretching of the nonpolar domain, thus, increasing its size. At the concentration examined in this work, [Formula: see text]-octane is found to be only partially miscible with the ionic liquid. The polar network is maintained; however, the continuous cationic nonpolar domain is split into multiple domains. [Formula: see text]-octane is accommodated in the ionic liquid nonpolar domain. Similarly, the amphiphilicity of 1-octanol leads to an increase in the number of cationic as well as anionic domains. The overall nonpolar domain length, however, remains nearly identical to that found for the pure ionic liquid. Additional characterization of structural features of the three systems is discussed in terms of one-dimensional number densities, nematic order parameters for the overall systems and their components and structure factors.

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40

Baranchikov, Alexander E., Mikhail I. Razumov, Svetlana V. Kameneva, Madina M. Sozarukova, Tatiana S. Beshkareva, Arina D. Filippova, Daniil A. Kozlov, Olga S. Ivanova, Alexander B. Shcherbakov y Vladimir K. Ivanov. "Facile Synthesis of Stable Cerium Dioxide Sols in Nonpolar Solvents". Molecules 27, n.º 15 (7 de agosto de 2022): 5028. http://dx.doi.org/10.3390/molecules27155028.

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A method is proposed for the preparation of stable sols of nanocrystalline cerium dioxide in nonpolar solvents, based on surface modification of CeO2 nanoparticles obtained by thermal hydrolysis of concentrated aqueous solutions of ammonium cerium(IV) nitrate with residues of 2-ethylhexanoic and octanoic acids. The synthesis was carried out at temperatures below 100 °C and did not require the use of expensive and toxic reagents. An assessment of the radical-scavenging properties of the obtained sols using the superoxide anion-radical neutralization model revealed that they demonstrate notable antioxidant activity. The results obtained indicate the potential of the nanoscale cerium dioxide sols in nonpolar solvents to be used for creating nanobiomaterials possessing antioxidant properties.

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41

Nezbeda, Ivo y Michael Rouha. "Extended excluded volume: Its origin and consequences". Pure and Applied Chemistry 85, n.º 1 (4 de octubre de 2012): 201–10. http://dx.doi.org/10.1351/pac-con-12-04-04.

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In contrast to the common intuitive/speculative approach based on an analysis of thermodynamic or structural data of (nonpolar) fluids, the statistical mechanical approach is used to extend the excluded volume concept to all other types of fluids. The (extended) excluded volume incorporates, in addition to common nonelectrostatic interactions defining the shape and size of the molecules, also the short-range part of the repulsive interactions between the embedded Coulombic sites. In this study we show that the extended excluded volume concept correctly predicts the behavior of the partial molar volume (PMV) at infinite dilution in different solvents and, particularly, differences between nonpolar and associating solvents. The concept is then applied to estimate the PMV of methanol in water.

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42

Reichardt, Christian, Stefan Löbbecke, Abdol Mohammed Mehranpour y Gerhard Schäfer. "Pyridinium N-phenoxide betaines and their application to the determination of solvent polarities, XXIV. Syntheses and UV-vis spectroscopic properties of new lipophilic tert-butyl- and 1-adamantyl substituted, negatively solvatochromic pyridinium N-phenolate betaine dyes". Canadian Journal of Chemistry 76, n.º 6 (1 de junio de 1998): 686–94. http://dx.doi.org/10.1139/v98-019.

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Syntheses and negative solvatochromism of two new lipophilic pentaphenyl pyridinium N-phenolate betaine dyes, substituted with seven tert-butyl groups (9) or with three tert-butyl and two 1-adamantyl groups (13) in the peripheral phenyl rings, are described in order to get zwitterionic dyes that are more soluble in nonpolar solvents such as the standard betaine dye, 1, which has been used for the construction of an empirical scale of solvent polarity, called the ET(30) scale.Key words: betaine dyes, ET(30) values, lipophilic dyes, pyridinium N-phenolate betaine dyes, solvatochromism, solvent polarity.

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43

Xing, Xiaoyu y Yan Zhao. "Intramolecularly enhanced molecular tweezers with unusually strong binding for aromatic guests in unfavorable solvents". Organic & Biomolecular Chemistry 16, n.º 21 (2018): 3885–88. http://dx.doi.org/10.1039/c8ob00786a.

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44

Jen, Myungsam, Sebok Lee y Yoonsoo Pang. "Excited‐State Dynamics of All‐trans‐Retinal Investigated by Time‐resolved Electronic and Vibrational Spectroscopy^#". Bulletin of the Korean Chemical Society 36, n.º 3 (26 de febrero de 2015): 900–905. http://dx.doi.org/10.1002/bkcs.10168.

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Time‐resolved electronic and vibrational spectroscopy has been applied to understand ultrafast excited state dynamics of all‐trans‐retinal. Femtosecond transient absorption spectroscopy provides an overview of the excited‐state dynamics of all‐trans‐retinal, and femtosecond‐stimulated Raman and infrared absorption measurements, which have not been reported previously, provide further details of the structural changes in the excited states. Three singlet excited states and one triplet excited state have been identified from these experimental results, which are in good agreement with many previous reports. A change in the energy order of the singlet excited state of all‐trans‐retinal between in polar and nonpolar solvents abruptly modifies the excited state dynamics. The intersystem crossing to the T1 state from the S1 state (nπ*) almost disappears in polar solvents, whereas the fluorescence from S3 and S2 states (ππ*) is almost absent in nonpolar solvents.

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45

Grabner, G., G. Koehler, G. Marconi, S. Monti y E. Venuti. "Photophysical properties of methylated phenols in nonpolar solvents". Journal of Physical Chemistry 94, n.º 9 (mayo de 1990): 3609–13. http://dx.doi.org/10.1021/j100372a045.

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46

Kowert, Bruce A. "Diffusion of Benzene and Alkylbenzenes in Nonpolar Solvents". Journal of Physical Chemistry B 122, n.º 6 (7 de febrero de 2018): 1940–47. http://dx.doi.org/10.1021/acs.jpcb.7b10078.

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47

Kowert, Bruce A. "Diffusion of Polymethylene Chain Molecules in Nonpolar Solvents". Journal of Physical Chemistry B 124, n.º 18 (23 de abril de 2020): 3716–23. http://dx.doi.org/10.1021/acs.jpcb.0c00063.

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48

Smith, Gregory N., Sarah L. Canning, Matthew J. Derry, Elizabeth R. Jones, Thomas J. Neal y Andrew J. Smith. "Ionic and Nonspherical Polymer Nanoparticles in Nonpolar Solvents". Macromolecules 53, n.º 8 (13 de abril de 2020): 3148–56. http://dx.doi.org/10.1021/acs.macromol.0c00121.

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49

Rospenk, Maria y Aleksander Koll. "Self-assembly of 2-aminopyrimidines in nonpolar solvents". Journal of Molecular Structure 844-845 (noviembre de 2007): 232–41. http://dx.doi.org/10.1016/j.molstruc.2007.04.010.

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50

Schwarz, Harold A. "Partial molar volumes of ions in nonpolar solvents". Journal of Physical Chemistry 97, n.º 49 (diciembre de 1993): 12954–58. http://dx.doi.org/10.1021/j100151a051.

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