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Journal articles on the topic 'Basic media and aprotic solvent'

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Published: 4 June 2025

Last updated: 15 July 2025

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Janderka, Pavel, Oldřich Fischer, and Eva Fischerová. "Effect of the Solvent Basicity and Additives on the Electroreduction of Picric Acid and Tetramethylammonium Picrate in Aprotic Media." Collection of Czechoslovak Chemical Communications 62, no. 4 (1997): 581–96. http://dx.doi.org/10.1135/cccc19970581.

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The electroreduction of picric acid and tetramethylammonium picrate in acetonitrile, acetone, N,N-dimethylformamide, dimethyl sulfoxide and hexamethylphosphoramide has been studied by normal pulse polarography, cyclic voltammetry and by coulometric analysis. The reduction of undissociated acid starts in all aprotic media with consumption of one electron. The reduction potential is shifted to more negative potentials with rising basicity of the solvent, i.e. with rising dissociation constant of picric acid. The formation of anion radicals is followed by the sequence of acido-basic selfprotonation reactions as well as by the disproportionation leading to a nitroso intermediate. The reduction mechanism does not change by addition of proton acceptor (basic alumina) or by amfiprotic species (anthranilic acid). In the presence of a strong acid, picric acid can mediate the electroreduction of added protons. Proposed mechanisms were supported by comparison with electrochemical behaviour of related nitrophenols in the same aprotic media.

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Nevěčná, Taťjana, Vojtěch Bekárek, and Oldřich Pytela. "A Study of Effects of Temperature and Medium on Reaction of Triethylamine with Ethyl Bromide." Collection of Czechoslovak Chemical Communications 59, no. 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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Kankaanperä, Alpo, Pirketta Scharlin, Ilona Kuusisto, Riitta Kallio, and Emma Bernoulli. "Ureas and amides as dipolar aprotic solvents in highly basic media. The dependence of kinetic basicity on solvent composition." Journal of the Chemical Society, Perkin Transactions 2, no. 2 (1999): 169–74. http://dx.doi.org/10.1039/a808435a.

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Morteza, Shiri, Farajpour Behnaz, Bozorgpour-Savadjani Zahra, et al. "Transition-metal free highly selective aerobic oxidation of hindered 2-alkylindoles." Tetrahedron 71, no. 34 (2015): 5531–37. https://doi.org/10.1016/j.tet.2015.06.065.

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A novel and easy access to highly complex 3-oxoindolin-2-ylidene derivatives from the exposure of Ugiadducts bearing an indolyl moiety in Cs2CO3/DMF to air is reported. This is the first example of aerobic oxidation of 2-alkylindoles to 3-oxoindolin-2-ylidenes. Some advantages of this method are the use of air as oxygen source, transition metal-free reagents and simple conditions, a multicomponent and one-pot process and highly regioand stereoselective manner to trans-3-oxoindolin-2-ylidenes.

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Petukhov, Dmitrii I., Dmitrii A. Buldakov, Alexey A. Tishkin, Alexey V. Lukashin, and Andrei A. Eliseev. "Liquid permeation and chemical stability of anodic alumina membranes." Beilstein Journal of Nanotechnology 8 (March 6, 2017): 561–70. http://dx.doi.org/10.3762/bjnano.8.60.

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A study on the chemical stability of anodic alumina membranes and their performance in long-term water and organic solvent permeation experiments is reported. Anodic alumina possesses high stability for both protonic and aprotonic organic solvents. However, serious degradation of the membrane occurs in pure water, leading to a drastic decrease of permeance (over 20% of the initial value after the passing of 0.250 m3/m2 of pure water). The drying of the membrane induces further permeance drop-off. The rate of membrane degradation strongly depends on the pH of the penetrant solution and increases in basic media. According to 27Al NMR and thermogravimetry results, the degradation of the membranes is associated with the dissolution of water-soluble [Al13O4(OH)24(H2O)12]7+ polyhydroxocomplexes and their further redeposition in the form of [Al(OH)4]−, resulting in channels blocking. This process intensifies in basic pH due to the high positive charge of the anodic alumina surface. An approach for improving anodic aluminum oxide stability towards dissolution in water by carbon CVD coating of the membrane walls is suggested.

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Mchedlov-Petrossyan, Nikolay O. "Nikolai Izmailov (1907-1961): An appreciation." Pure and Applied Chemistry 80, no. 7 (2008): v. http://dx.doi.org/10.1351/pac20088007v.

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The International Conference on Modern Physical Chemistry for Advanced Materials was organized primarily to commemorate the centenary of the birth of Prof. Nikolai Izmailov and to pay tribute to his scientific achievements and legacy. Nikolai Arkadievich Izmailov was born in Sukhumi, in the southern region of the Russian Empire, on 22 June 1907. After his family moved to Kharkov (in Ukrainian: Kharkiv), he developed an early interest in chemistry and eventually enrolled as a Ph.D. student at Kharkov State University (at that time, it was called the Kharkov Institute of Public Education) in 1928. He initially conducted research into sorption of gases, under the guidance of Prof. Kosakevitch. Thereafter, he investigated the influence of salts on adsorption of organic molecules on water/air interface. He received his Ph.D. in 1937.From 1934, conducting his research at the University, he started a joint appointment at Kharkov Pharmaceutical Research Institute, and his independent scientific interests developed along two main directions, namely, static and dynamic properties of sorption from solutions and the influence of the solvent on dissociation of electrolytes. It was here that he collaborated with Maria Shraiber to introduce the "drop-chromatographic method" in 1938, which later became known as thin layer chromatography (TLC). This finding is widely recognized and acclaimed, and continues to play an essential role in everyday laboratory practice. At a time when one of the most promising methods of drug analysis was titrimetry, and in the course of his work at the Pharmaceutical Institute, Izmailov also became interested in using nonaqueous solvents for this purpose. He recognized that water is the most atypical of solvents, and tried to rationalize the origin of the then-novel concept of the differentiating influence of organic solvents on acid-base properties. Throughout the 1930s, Izmailov investigated the possibility of employing indicator electrodes, especially glass electrodes, in organic solvents.In 1944, Izmailov headed the Department of Physical Chemistry at the University. In his Sc.D. dissertation presented in 1948, as well as in his publications during the 1950s, he proposed a scheme of dissociation of electrolytes in solutions, which is recognized as probably the most complete. The main point, in respect to acids, was based on the idea of improving the fundamental but somewhat schematic Brønsted's theory, by considering solvation of all the equilibrium species. Just this viewpoint rationalized the differentiating action of solvents on the strength of acids (i.e., unequal changes in their dissociation constants). A seminal review published in 1950 bore the title of his dissertation, "The influence of solvents on the strength of acids", and presented a comprehensive and lucid classification of nonaqueous solvents according to the character of their levelling and differentiating influence on acids strength. He proposed the following groupings of solvents: (i) amphoteric, such as water and alcohols; (ii) mixtures of alcohols and dioxane with water; (iii) acidic solvents, such as formic, acetic, propionic acids, sulfuric acid and its mixtures with water, and liquid hydrogen halides; (iv) basic solvents, such as ammonia, hydrazine, pyridine, etc.; (v) aprotic solvents: benzene, chlorobenzene, etc.; (vi) "differentiating" solvents. The latter category, exemplified by nitriles, nitro compounds, aldehydes, ketones, and amides, had by then been known to differentiate strength of salts due to Walden's papers. Izmailov significantly elaborated this concept and adapted it to acids and bases, taking into consideration solvation effects. In fact, this significant group of solvents (vi) is now known as dipolar aprotic (A. Parker) or dipolar non-hydrogen-bond donor (HBD) solvents (F. Bordwell).In order to interpret the pKa shifts, the transfer activity coefficients of ions were divided into two parts. As a result, a general equation was proposed for the difference between the pKa in the organic solvent and in water, which included both the so-called Born term, already used by Brønsted, and the item reflecting other solvation effects. Actually, this was a unification of electrostatic approaches (Brønsted, Wynne-Jones, Gurney) and "chemical" theory of solvation (in the spirit of Mendeleyev and Kablukov).This was a decisive step toward the understanding of the multiplicity of solvent effects. In order to reveal the peculiarities of solvation of molecules, Izmailov compared interaction between acids (carboxylic acids and phenols) and alcohols on the one hand and ketones, nitriles, etc., on the other, using the "inert" solvents as media. Besides, Izmailov underlined the significance of degree of charge delocalization in conjugated anions (i.e., carboxylate and phenolate) with respect to alterations in the strength of corresponding acids in organic solvents; later, such ideas grew very popular. These concepts enabled the different changes in dissociation constants of acids belonging to the same "charge type" to be rationalized, but to different "chemical types" on going from water to organic solvents, despite Brønsted's theory, a general effect that had already been stressed by Verhoek. In Izmailov's scheme of electrolytic dissociation, the possibility of the existence of ion pairs between solvated proton and anion of the acid was foreseen. Indeed, he had even alluded to this in his dissertation completed in 1947. Accordingly, for dissociation of salts CA, the scheme not only took into account solvated species (C+A-)solv, free solvated ions C+solv, and Asolv, but postulated also associates of solvated ions, C+solvAsolv. The latter can be considered as a prototype of the so-called solvent-separated, or loose, or long ion pairs C+//A-.Izmailov and his associates continued studying acids, bases, and salts in alcohols, polar and nonpolar aprotic (non-HBD) solvents, acidic and basic solvents, mainly by potentiometry; the results of their exhaustive research were presented in a vast series of papers under the title "Thermodynamic properties of electrolytes in nonaqueous solutions" published in the Russian Journal of Physical Chemistry, as well as in other publications. Izmailov proposed several new methods for estimating activity coefficients of ion transfer from water to nonaqueous solvents and Gibbs energy of ion solvation and generalized the concept of unique (unified) acidity scale in different solvents. The most monumental of Izmailov's contributions was the treatise "Electrochemistry of solvents", which was published in Russian in 1959. Most of the original sections of this voluminous 958-page work, devoted to the detailed scheme of electrolytic dissociation, differentiating action of solvents, solvation, etc., were completely reviewed in the excellent monograph of Shatenshtein, which was translated into English and thus became available to international readership. This major contribution is well known to those working in the field of solution chemistry and is still frequently cited.Izmailov also continued his early studies on the behavior of glass electrode in different solvents. He made a considerable contribution to the theory of physicochemical analysis. In Ukraine, Izmailov was one of the pioneers in the application of radioactive indicators to physical chemistry. The latter were used by him both for studying solubility and solvation of salts and to gain understanding of the response mechanism of glass electrodes. Izmailov was among the first who used Volta cells for determination of real solvation energies and activity coefficients of single ions. At the end of the 1950s, he applied quantum chemistry to estimate proton affinities and ionic solvation energies.The untimely death of Nikolai Izmailov in 1961 was a loss to science, but his prolific output of over 280 publications ensures his place in the records of modern physical chemistry. This appreciation introduces a collection of works that would surely have captured his interest and will serve to honor his memory. A more detailed and personalized account of the man and the times in which he lived and achieved will be published in the September 2008 issue of Chemistry International and furnishes a link to a short bibliography listing some of his seminal publications.Nikolay O. Mchedlov-PetrossyanV. N. Karazin National University

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Bowden, Keith, and Shyla Prasannan. "Reactions in strongly basic media. Part 8. Correlation of the rates of alkaline hydrolysis of 2,4-dinitroanisole and 2-methoxy-5-nitropyridine in aqueous dipolar aprotic solvents with acidity functions. An order of basicity for aqueous dipolar aprotic solvents." Journal of the Chemical Society, Perkin Transactions 2, no. 2 (1987): 185. http://dx.doi.org/10.1039/p29870000185.

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Panteleev, S. V., S. V. Maslennikov, A. N. Egorochkin, and V. Yu Vakulenko. "Solvent effect on metal oxidation rates in aprotic media." Russian Journal of General Chemistry 77, no. 6 (2007): 1004–7. http://dx.doi.org/10.1134/s1070363207060084.

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Kushch, S. D. "Nitrobenzene Hydrogenation to N-phenylhydroxylamine: a New Approach to the Selectivity." Eurasian Chemico-Technological Journal 4, no. 1 (2017): 19. http://dx.doi.org/10.18321/ectj513.

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A new approach to resolve the problem of selectivity with respect to N-phenylhydroxylamine in nitrobenzene hydrogenation is proposed. N-phenylhydroxylamine only is the final product of nitrobenzene electroreduction in aprotic media. In this case nitrobenzene reduction carries out by alternation of electrochemical (electron transfer) and chemical (species formed protonation) stages i.e. by so-called EC mechanism. Such mechanism realization in nitrobenzene hydrogenation is possible if i) a catalyst activates hydrogen as “hydrogen electrode” i.e. serves electrons source; ii) a reaction media contains limiting proton concentration. These limitations are discharged in the media of aprotic dipolar solvent, which solvated both positive and negative species. Really, in aprotic dipolar solvents over reduced platinum complexes or lowpercentage (≤1 wt.%) platinum, iridium or osmium catalyst nitrobenzene is hydrogenated with process discontinuance after nitrobenzene total consumption. Nitrobenzene hydrogenation yields N-phenylhydroxylamine as the main (the yield is 98%) product. As these low-percentage catalysts, complex catalyst in situ is heterogeneous i.e. it represents a platinum colloid (particle size ~ 40 nm) stabilized by aprotic dipolar solvent. So, process of nitrobenzene hydrogenation, which is similar to nitrobenzene electoreduction, can is created. A kinetic scheme proposed is analyzed and kinetic equation for initial reaction rate, which is conformed to kinetic data, is obtained.

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Amanchukwu, Chibueze. "(Invited) Manipulating Water Using Aprotic Solvents for CO2 Electrochemical Reduction." ECS Meeting Abstracts MA2024-02, no. 62 (2024): 4164. https://doi.org/10.1149/ma2024-02624164mtgabs.

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Carbon dioxide (CO2) electrochemical conversion is vital because it provides a pathway to efficiently valorize CO2 and incentivize CO2 capture. Electrocatalytic CO2 reduction reaction (CO2RR) is of great interest because it is scalable and can be done at ambient temperature and pressure. However, these reactions are typically performed in water which suffers from undesired hydrogen evolution reaction (HER) from water breakdown. Aprotic nonaqueous electrolytes can suppress HER and enable a wider range of catalysts for CO2RR. However, water is still needed as a proton source and to stabilize charged intermediates. Here, we study the influence of aprotic electrolyte solvent on modulating the water microenvironment, solvation, and dynamics for CO2RR. Furthermore, we probe changes to the water chemical environment in different aprotic media and the ability of aprotic electrolytes to enhance CO2RR or suppress HER. Our work pushes the field in the understanding of electrolyte solvent and water effects for electrochemical transformations such as CO2RR and HER.

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Chmurzynski, L., and Z. Warnke. "Acid-Base Equilibria of Substituted Pyridine N-Oxides in N,N-Dimethylformamide and Dimethyl Sulfoxide." Australian Journal of Chemistry 46, no. 2 (1993): 185. http://dx.doi.org/10.1071/ch9930185.

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Acidity constants have been determined potentiometrically for a variety of conjugate acids of substituted pyridine N-oxides in N,N- dimethylformamide ( dmf ) and dimethyl sulfoxide ( dmso ). The pKa values in these solvents varied in the same direction and correlated with the pKa values of these species in water and in the protophobic aprotic solvent acetonitrile. Further, a linear relationship has been established between the pKa values in the two protophilic aprotic solvents under study. The most basic substituted pyridine N-oxides exhibited a weak tendency towards cationic homoconjugation in dmf , whereas in the more basic dmso the homoconjugation equilibrium was not established for any of the heterocyclic N-oxides. The phenomenon of cationic homoconjugation was also not observed with pyridine as a representative of heterocyclic amines, both in dmf and dmso. This finding complies with the results obtained in other polar aprotic solvents.

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Nagy, Otto B., Victor Reuliaux, Nicole Bertrand, Anne van Der Mensbrugghe, Jean Leseul, and Janos B. Nagy. "Mechanism of Ester Aminolysis in Aprotic Media and Specific Solvent Effects." Bulletin des Sociétés Chimiques Belges 94, no. 11-12 (2010): 1055–74. http://dx.doi.org/10.1002/bscb.19850941127.

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Wagnerczauderna, E., and MK Kalinowski. "Hammett-Streitwieser Reaction Constants for the Electroreduction of Diaryl Ketones in Aprotic Media." Australian Journal of Chemistry 49, no. 8 (1996): 901. http://dx.doi.org/10.1071/ch9960901.

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Cyclic voltammetry has been used to measure formal potentials of seven aromatic ketone/ketyl radical anion systems in benzonitrile, acetonitrile , propylene carbonate, acetone, N,N- dimethylformamide, N-methylpyrrolidin-2-one, dimethyl sulfoxide and hexamethylphosphoric triamide. The values measured in each solvent obey the Hammett- Streitwieser equation; the reaction constants were found to depend on the solvent acidity and basicity expressed by acceptor and donor numbers, respectively. The results are discussed in terms of the solvation of the products and reactants of the electrode reaction.

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Smith, Gregory N. "Proton transfer in nonpolar solvents: an approach to generate electrolytes in aprotic media." Physical Chemistry Chemical Physics 20, no. 28 (2018): 18919–23. http://dx.doi.org/10.1039/c8cp02349b.

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Fejzic, Hannah, Ritesh Kumar, Reginaldo Gomes, et al. "Water Clustering Modulates Activity and Enables Hydrogenated Product Formation during Carbon Monoxide Electroreduction in Aprotic Media." ECS Meeting Abstracts MA2024-02, no. 62 (2024): 4250. https://doi.org/10.1149/ma2024-02624250mtgabs.

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As the effects of climate change are becoming increasingly visible, carbon dioxide electroreduction reaction (CO2RR) is gaining popularity to convert waste carbon dioxide to value-added products. As carbon monoxide (CO) is a key intermediate for valuable products such as methane and ethylene, CORR is studied to bypass CO2 activation. Most of the work on CO2RR and CORR has focused on using water as a proton source as water’s hydrogen bonding supports key intermediates and acts as a proton source for hydrogenated products. Using nonaqueous solvents instead of water decreases the competitive hydrogen evolution reaction (HER) from water breakdown. Additionally mixed aqueous-nonaqueous systems allow for fundamental understanding of water’s role in electrochemical transformations when it is only available in limited quantities as a proton source. Here, we experimentally control water speciation and activity using aprotic solvent media during CORR. Remarkably, we show that aprotic solvents that support microheterogeneous water-water clusters leads to significant amounts of CORR products (methane and ethylene) with a maximum ethylene Faradaic efficiency of 22% in acetonitrile (χH2O = 0.2); the first report of CORR to C2+ products using water in an aprotic solvent. In contrast, microhomogeneous systems – where water integrates into the solvents’ intermolecular binding network at all length scales and has lower water activity – primarily support undesired HER. Insights gained expand our understanding of water activity and nonaqueous electrolyte design for other important transformations reactions beyond CO reduction such as CO2RR and HER.

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Carter, Stephen J., Bruce M. Foxman, and Louis S. Stuhl. "Cobalt(II) cyanides in aprotic media: effect of varying counterion and solvent." Inorganic Chemistry 25, no. 16 (1986): 2888–94. http://dx.doi.org/10.1021/ic00236a046.

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Akatyev, Nikolay. "THEORETICAL INVESTIGATION OF 2,6-DIFLUORO-4-NITROANILINE WITH SEMI-EMPIRICAL LEVELS OF THEORY." DULATY UNIVERSITY BULLETIN 3, no. 11 (2023): 145–53. http://dx.doi.org/10.55956/huyg3105.

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Abstract. In this work quantum chemical approach was applied in order to investigate the electronic structure and certain properties of 2,6-difluoro-4-nitroaniline with a series of semi-empirical methods using the GAMESS software. Protic and aprotic Polarized Continuum solvent models were used to study the influence of the media to the electronic structure and geometry of the molecule. It has been found that calculations using solvent models make possibility to obtain more accurate results than for vacuum. The comparison of calculated results with the available XRD crystallographic data shows that all obtained values are within acceptable deviations.

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U., Arvind, and Kumar Sanjay. "Non-specific solvent effects on proton transfer equilibrium between toluic acids and carbinol base of crystal violet." Journal of Indian Chemical Society Vol. 87, Mar 2010 (2010): 361–63. https://doi.org/10.5281/zenodo.5779115.

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Department of Chemistry, Rajendra College, Chapra-841 301, Bihar, India Department of Chemistry, Jagdam College, Chapra-841 301, Bihar, India Manuscript received 27 April 2009, accepted 20 August 2009 Acid-base reactions In apolar aprotic media provide a sufficiently close measure of intrinsic acid/base strengths. A study on reaction equilibria between o- and m-methyl benzoic: (toluic) acids with the carbinol base of crystal violet in five apolar aprotic solvents of similar Kirkwood polarity function (\(\in\) - 1)/(2\(\in\)+ 1) and significantly different Dimroth Reichardt's ET (30) and Kamlet-Taft's polarity-polarisability 𝝅* parameter Indicates strongly the overall non-specific solvent effects are contributed by both electrostatic and dispersion interactions, the latter having a more dominant role therein.

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Carac, Andreea, Rica Boscencu, Andreea Veronica Dediu, Simona Gabriela Bungau, and Rodica Mihaela Dinica. "Solvent Effects on the Spectral and Electrochemical Properties of Some Pyridinium Quaternary Compounds." Revista de Chimie 68, no. 7 (2017): 1423–28. http://dx.doi.org/10.37358/rc.17.7.5688.

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The physicochemical properties and the redox potential of two pyridinium compounds, a diquaternary salt of 4,4�-bipyridinium (BP) and one of 1,2-bis(4-pyridyl)ethane (BPE) were studied. Cyclic voltammetry on platinum electrode was used to evaluate the solvent influence on the redox properties of the pyridinium compounds. Electrochemical measurements were performed in aqueous media, ethanol and aprotic solvent. The solvent variation causes changes in the electro-oxidation processes of the heterogeneous electron transfer at the applied potential. The presence of the ethylenic group in the structure of BPE presents slightly different electrochemical behaviour compared to BP. The corroboration of the electrochemical data with absorption spectral results attests that it�s more likely that the ECE sequence is responsible for the reduction mechanism of pyridinium compounds.

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Ābele, Līga, Ieva Baķe, Laimdota Vilcēna, and Silvija Kukle. "Development of Graphene-Based Functional Coating for the Surface Modification of Textiles." Materials Science Forum 1104 (November 10, 2023): 77–85. http://dx.doi.org/10.4028/p-i7kxsv.

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The objective of the presented research is to improve the ballistic performance of para-aramid woven fabric by deposition of graphene coatings directly on woven textile substrates. The improvement of mechanical properties of the ballistic fabric is attributed to the formation of a highly ordered layered structure and the efficient load transfer between the fabric fibers and the graphene nanosheets. The results of deposition of layered graphene coatings on woven textiles are discussed here. The pristine graphite directly subjected to a solvent treatment in this work, which resulted in the production of exfoliated graphene sheets in the form of a dispersion that allow immediate utilization obtained dispersion for deposition on the para-aramid samples. In order to prepare the dispersion, graphite flakes were first dispersed into liquid media followed by graphite intercalation (division into microlayers) and nano-layers exfoliation. Dipolar aprotic organic solvent DMAc (N,N-Dimethylacetamide) and Cyrene (Dihydrolevoglucosenone) as a bio-based alternative for dipolar aprotic solvents were used as main components of liquid media. At the final stage, a stable dispersion of isolated flakes by using two types of liquid medium was obtained. To study the effects of dip coating and rolling parameters, six kinds of samples with different pull-out speeds and compression ratios were prepared, and their functional properties were measured and compared.

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Perfilov, Maxim M., Elvira R. Zaitseva, Nadezhda S. Baleeva, et al. "Meta-CF3-Substituted Analogues of the GFP Chromophore with Remarkable Solvatochromism." International Journal of Molecular Sciences 24, no. 12 (2023): 9923. http://dx.doi.org/10.3390/ijms24129923.

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In this work, we have shown that the introduction of a trifluoromethyl group into the me-ta-position of arylidene imidazolones (GFP chromophore core) leads to a dramatic increase in their fluorescence in nonpolar and aprotic media. The presence of a pronounced solvent-dependent gradation of fluorescence intensity makes it possible to use these substances as fluorescent polarity sensors. In particular, we showed that one of the created compounds could be used for selective labeling of the endoplasmic reticulum of living cells.

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AlMarzouq, Douaa Salman, and Noha M. Hilmy Elnagdi. "Glycerol and Q-Tubes: Green Catalyst and Technique for Synthesis of Polyfunctionally Substituted Heteroaromatics and Anilines." Molecules 24, no. 9 (2019): 1806. http://dx.doi.org/10.3390/molecules24091806.

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The role of glycerol as a green bio-based solvent, reactant, and/or a catalyst in the synthesis of novel heterocycles, under pressure, is studied. Synthesis of novel quinolines in good yields using a new modified Skraup synthesis, utilizing glycerol and pressure Q-tubes, is demonstrated. Novel aniline trimers are prepared using glycerol, and substituted anilines under pressure, in acidic medium and water. Glycerol was employed as a catalyst and a green solvent in the synthesis of novel pyridazines 13a–c. The mechanisms of the reactions and the catalytic effect of glycerol in protic and aprotic media are fully discussed. The structures of the synthesized compounds were determined via X-ray crystallography and spectroscopic methods.

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Mazloum-Ardakani, Mohammad, Shahram Lotfi, Jahanbakhsh Ghasemi, Alahdad Shababi, and Mohammad Noroozi. "Spectrophotometric determination of the acidity constants of calcon in water and mixed water-organic solvents." Journal of the Serbian Chemical Society 74, no. 2 (2009): 159–69. http://dx.doi.org/10.2298/jsc0902159m.

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The acid-base properties of calcon (1-(2-hydroxy-1-naphthylazo)-2- -naphthol-4-sulfonic acid) in water and mixed water-organic solvents at 25 ?C at an ionic strength of 0.10 M are studied by a multiwavelength spectrophotometric method. The organic solvents used were the amphiprotic (methanol), dipolar aprotic (dimethylsulfoxide), and low basic aprotic (acetonitrile). To evaluate the pH absorbance data, a resolution method based on the combination of soft- and hard-modeling was applied. The acidity constants of all related equilibria were estimated using the whole spectral fitting of the collected data to an established factor analysis model. The data analysis program Datan was applied for determination of the acidity constants. The corresponding pKa values were determined in water and mixed water-organic solvents. Linear relationship between the acidity constants and the mole fraction of the different solvents in the mixtures exist. The effect of solvent properties on acid-base behavior is discussed.

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Verma, Sanno. "EFFECT OF AQUO-N-PROPANOL SOLVENT SYSTEMS ON THE MEDICINAL EFFICIENCY OF HEAVY PROPIONATES." SCHOLARLY RESEARCH JOURNAL FOR INTERDISCIPLINARY STUDIES 9, no. 69 (2021): 16489–98. http://dx.doi.org/10.21922/srjis.v9i69.10048.

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For highlighting the Solvent-effect of a diapolar aprotic solvent, n-propanol on the biochemical behaviour of propionate ester, the kinetics of alkali catalysed hydrolysis of butyl propionate was carried out in aquo-n-propanol solvent systems having different concentration of the organic component (n-propanol) varying from 20 to 80% (v/v) at different temperatures ranging from 20 to 40°C. The number of water molecules associated with the activated complex of the reaction were found to increase from 0.338 to 1.401 and from this, it is it inferred that n-propanol acts as structure breaker of water converting its dense form into bulky form and it changes the mechanistic path way of the reaction from bimolecular to unimolecular, From the numerical value of the kinetic temperature of the reaction, which is evaluated to be 281.0, it is concluded that there is weak but appreciable interaction between solvent and solute in the reaction media.

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Pytela, Oldřich. "A new classification of solvents based on chemometric empirical scale of parameters." Collection of Czechoslovak Chemical Communications 55, no. 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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Milescu, Roxana A., C. Robert McElroy, Thomas J. Farmer, Paul M. Williams, Matthew J. Walters, and James H. Clark. "Fabrication of PES/PVP Water Filtration Membranes Using Cyrene®, a Safer Bio-Based Polar Aprotic Solvent." Advances in Polymer Technology 2019 (July 7, 2019): 1–15. http://dx.doi.org/10.1155/2019/9692859.

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A more sustainable dialysis and water filtration membrane has been developed, by using the new, safer, bio-based solvent Cyrene® in place of N-methyl pyrrolidinone (NMP). The effects of solvent choice, solvent evaporation time, the temperature of casting gel, and coagulation bath together with the additive concentration on porosity and pore size distribution were studied. The results, combined with infrared spectra, SEM images, porosity results, water contact angle (WCA), and water permeation, confirm that Cyrene® is better media to produce polyethersulfone (PES) membranes. New methods, Mercury Intrusion Porosimetry (MIP) and NMR-based pore structure model, were applied to estimate the porosity and pore size distribution of the new membranes produced for the first time with Cyrene® and PVP as additive. Hansen Solubility Parameters in Practice (HSPiP) was used to predict polymer-solvent interactions. The use of Cyrene® resulted in reduced polyvinylpyrrolidone (PVP) loading than required when using NMP and gave materials with larger pores and overall porosity. Two different conditions of casting gel were applied in this study: a hot (70°C) and cold gel (17°C) were cast to obtain membranes with different morphologies and water filtration behaviours.

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Sukhanova, Tatyana E., Andrey L. Didenko, Ilya L. Borisov, et al. "Morphological Analysis of Poly(4,4′-oxydiphenylene-pyromellitimide)-Based Organic Solvent Nanofiltration Membranes Formed by the Solution Method." Membranes 12, no. 12 (2022): 1235. http://dx.doi.org/10.3390/membranes12121235.

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Poly-(4,4′-oxydiphenylene) pyromellitimide or Kapton is the most widely available polyimide with high chemical and thermal stability. It has great prospects for use as a membrane material for filtering organic media due to its complete insolubility. However, the formation of membranes based on it, at the moment, is an unsolved problem. The study corresponds to the rediscovery of poly(4,4′-oxydiphenylene–pyromellitimide)-based soluble copoly(urethane-imides) as membrane polymers of a new generation. It is shown that the physical structure of PUI films prepared by the solution method becomes porous after the removal of urethane blocks from the polymer, and the pore size varies depending on the conditions of thermolysis and subsequent hydrolysis of the membrane polymer. The film annealed at 170 °C with a low destruction degree of polycaprolactam blocks exhibits the properties of a nanofiltration membrane. It is stable in the aprotic solvent DMF and has a Remasol Brilliant Blue R retention coefficient of 95%. After the hydrolysis of thermally treated films in acidic media, ultrafiltration size 66–82 nm pores appear, which leads to an increase in the permeate flow by more than two orders of magnitude. This circumstance provides opportunities for controlling the membrane polymer structure for further optimization of the performance characteristics of filtration membranes based on it. Thus, we proposed a new preparation method of ultra- and nanofiltration membranes based on poly(4,4′-oxydiphenylene–pyromellitimide) that are stable in aprotic solvents.

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Kolling, Orland W. "Solvent Reaction Field Effects upon the Trans/Gauche Conformational Equilibrium of 1,2-Dichloroethane in Aprotic Media." Transactions of the Kansas Academy of Science (1903-) 101, no. 3/4 (1998): 89. http://dx.doi.org/10.2307/3627955.

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Omer, M. E., A. M. Qandil, A. S. Ali, and H. J. Habib. "Preparation and solubility profile study of sodium and potassium salts of mefenamic acid: the effect of pH and polarity." Digest Journal of Nanomaterials and Biostructures 16, no. 2 (2021): 443–54. http://dx.doi.org/10.15251/djnb.2021.162.443.

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Enhancing the solubility of active pharmaceutical ingredients became a fundamental concept in the manufacturing of different pharmaceutical dosage forms. This research aims to enhance the solubility of mefenamic acid by salt formation method and study the effect of polarity, pH, and temperature on the solubility of mefenamic acid and its salts. Two deferent salts of mefenamic acid (sodium and potassium salts) were prepared. Using the asymmetric factorial as an experimental design, the solubility of mefenamic acid (MA), sodium mefenamate (Na-MA), and potassium mefenamate (K-MA) were studied in different solvents, pH, and temperatures. It has been found that potassium mefenamate has the highest solubility among other derivatives in different media. Also, the mefenamic acid and its salts have a higher solubility in the polar aprotic solvent and the higher pH aqueous media.

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Nielson, Roger M., George E. McManis, and Michael J. Weaver. "Solvent relaxation in electron-transfer reactions: comparisons between barrier-crossing dynamics in water and polar aprotic media." Journal of Physical Chemistry 93, no. 12 (1989): 4703–6. http://dx.doi.org/10.1021/j100349a005.

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Preda, Loredana, and Elena Volanschi. "Electrochemical study and MO — modeling of the reduction behaviour of some arylidene substituted derivatives of dibenz [b,e]-thiepin-5,5-dioxide-11-one." Open Chemistry 7, no. 3 (2009): 486–93. http://dx.doi.org/10.2478/s11532-009-0046-7.

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AbstractThe electrochemical reduction of four arylidene substituted derivatives of dibenz-[b,e]-thiepin-5,5-dioxide-11- one has been studied by cyclic voltammetry on platinum (Pt) electrode in aprotic media (DMSO), coupled with spectral EPR techniques. From the analysis of cyclic voltammetry experiments, aided by digital simulations using DigiSim software, the kinetic and thermodynamic parameters were evaluated for each system. The electrochemical behaviour is strongly directed by the nature of the arylidene substituents bound to the central heterocycle. The electrochemical investigation and solvent dependent semiempirical modeling using the PM3 hamiltonian in the frame of AMPAC program package allowed a rationalisation of experimental data regarding the electrochemical reduction and the reactivity of the intermediate species involved.

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Aditi, Shelke* Shritej Varhadi Dr. Lokhande R. P. Mahadik Jay Dhamane Yash. "Indole Synthesis: A Review and Medicinal Uses of Their Derivatives." International Journal of Pharmaceutical Sciences 3, no. 5 (2025): 4361–69. https://doi.org/10.5281/zenodo.15517986.

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A large variety of bioactive natural products and molecules with significant therapeutic value include indoles, a functional group that is widely distributed in nature. The development of new techniques for the synthesis of indole core and site-specific indoles has consequently increased exponentially. Greener techniques that employ solid acid catalysts, ionic liquids, water as a solvent, microwave irradiation, and solvent-free nanoparticles are replacing conventional methods for the synthesis of indoles. Additionally, the substituted indoles have a wide range of uses. 3-The sulfur-substituted indole derivative phenylthioindole has attracted attention because of its possible biological activity and use as a synthesis intermediary in medicinal chemistry. By nucleophilically substituting thiophenol for 3-haloindole under basic circumstances, this work describes an effective synthesis pathway for 3-phenylthioindole. In polar aprotic solvents, the reaction proceeds smoothly and produces the required thioether with excellent purity and good yield. Spectroscopic methods such as NMR, IR, and mass spectrometry were used to characterize the produced chemical. This technique provides a useful way to create sulfur-functionalized indole frameworks for additional research in medicinal chemistry.

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Kolling, Orland W. "Reaction Field Models for the Solvent Influence upon the Fundamental Carbonyl Vibrational Peak of 2-Butanone in Aprotic Media." Journal of Physical Chemistry 100, no. 40 (1996): 16087–91. http://dx.doi.org/10.1021/jp9617682.

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Bisz, Elwira, Pamela Podchorodecka, and Michal Szostak. "N -Methylcaprolactam as a Dipolar Aprotic Solvent for Iron-Catalyzed Cross-Coupling Reactions: Matching Efficiency with Safer Reaction Media." ChemCatChem 11, no. 4 (2019): 1196–99. http://dx.doi.org/10.1002/cctc.201802032.

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Tsoutsoura, Aikaterini, Zhiqi He, and Paschalis Alexandridis. "Phase Behavior and Structure of Poloxamer Block Copolymers in Protic and Aprotic Ionic Liquids." Molecules 28, no. 21 (2023): 7434. http://dx.doi.org/10.3390/molecules28217434.

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Ionic liquids are promising media for self-assembling block copolymers in applications such as energy storage. A robust design of block copolymer formulations in ionic liquids requires fundamental knowledge of their self-organization at the nanoscale. To this end, here, we focus on modeling two-component systems comprising a Poly(ethylene oxide)-poly (propylene oxide)-Poly(ethylene oxide) (PEO-PPO-PEO) block copolymer (Pluronic P105: EO37PO58EO37) and room temperature ionic liquids (RTILs): protic ethylammonium nitrate (EAN), aprotic ionic liquids (1-butyl-3-methylimidazolium hexafluorophosphate (BMIMPF6), or 1-butyl-3-methylimidazolium tetrafluoroborate (BMIMBF4). Rich structural polymorphism was exhibited, including phases of micellar (sphere) cubic, hexagonal (cylinder), bicontinuous cubic, and lamellar (bilayer) lyotropic liquid crystalline (LLC) ordered structures in addition to solution regions. The characteristic scales of the structural lengths were obtained using small-angle X-ray scattering (SAXS) data analysis. On the basis of phase behavior and structure, the effects of the ionic liquid solvent on block copolymer organization were assessed and contrasted to those of molecular solvents, such as water and formamide.

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Abdel-Mottaleb, M. S. A., H. R. Galal, A. F. M. Dessouky, et al. "Fluorescence and photostability studies of anthracene-9-carboxylic acid in different media." International Journal of Photoenergy 2, no. 1 (2000): 47–53. http://dx.doi.org/10.1155/s1110662x00000076.

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Electronic absorption and fluorescence spectra of anthracene-9-carboxylic acid (ANCA) were studied in different homogeneous solvents, binary protic/aprotic solvent mixtures and in heterogeneous solutions of the cationic cetyltrimethyl ammonium bromide (CTAB) micelle. Different chemical species of ANCA were identified spectroscopically in different media. The results are discussed on the basis of a mechanism that involves two equilibria: acid-base equilibrium and monomer-dimer equilibrium. These equilibria were found to be very sensitive to the nature of the medium and the concentration of ANCA.Moreover, while it is photostable in most solvents studied, the ANCA was found to be photolabile in aqueous media of different pHs. The acid-base catalyzed photodegradation rate was studied by following up absorption and/or fluorescence intensities as a function of illumination dose. The determined rate of the photochemical degradation of ANCA depends on the nature of the medium. The first order degradation rate constant is remarkably enhanced in heterogeneous medium of CTAB. As expected, the determined activation energy is low (∼3.2 kJ.mol-1). This result favors photooxidation process. Anthraquinone was the main photodegradation product obtainedvia9,9′-dicarboxylic head-to-head dimer of anthracene that was identified by GC-Mass technique.

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Keppeler, Miriam, Jürgen Holzbock, Johanna Akbarzadeh, Herwig Peterlik, and Nicola Hüsing. "Inorganic–organic hybrid materials through post-synthesis modification: Impact of the treatment with azides on the mesopore structure." Beilstein Journal of Nanotechnology 2 (August 26, 2011): 486–98. http://dx.doi.org/10.3762/bjnano.2.52.

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Hybrid, hierarchically organized, monolithic silica gels, comprising periodically arranged mesopores and a cellular macroscopic network, have been prepared through a co-condensation reaction of tetrakis(2-hydroxyethyl)orthosilicate with chloromethyl-trimethoxysilane or 3-(chloropropyl)-triethoxysilane. Subsequent conversion of the chloro groups into azido groups, by nucleophilic substitution with NaN3 in N,N-dimethylformamide, was conducted upon preservation of the monolithic structure. However, treatment with NaN3 had a strong influence on the structure in the mesoporous regime, with changes such as an increase of mesopore diameter, pore volume and lattice constants, as well as a concomitant decrease of the pore wall thickness, as confirmed by small angle X-ray scattering, transmission electron microscopy, and nitrogen sorption analysis. Similar effects were observed for unmodified silica gels by simple ageing in azide-containing media, whether a relatively small or a sterically demanding counter ion (Na+ or (H3C)4N+) was used. The structural modification did not seem to depend greatly on whether an organic aprotic solvent (N,N-dimethylformamide, 1,1,3,3-tetramethylurea, 1,3-dimethyl-2-imidazolidinone) or a protic solvent that can form hydrogen bonds, such as water, was used.

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Valverde, Clodoaldo, João Victor Batista Soares, André Duarte da Silva, et al. "Theoretical study of solvent effects on the hyperpolarizabilities of two chalcone derivatives." Revista Colombiana de Química 49, no. 1 (2020): 33–39. http://dx.doi.org/10.15446/rev.colomb.quim.v1n49.82156.

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The use of organic as nonlinear optical materials has been intensively explored in the recent years due to the ease of manipulation of the molecular structure and the synthetic flexibility regarding the change of substituent groups. In the present work, the linear and nonlinear properties of two chalcones derivatives (E)-1-(4-methylphenyl)-3-phenylprop-2-en-1-one (4MP3P) and (E)-1-(4-Nitrophenyl)-3-phenylprop-2-en-1-one (4NP3P), that differ by the substituent position at the phenyl ring, were studied in the presence of protic and aprotic solvents simulated by the Polarizable Continuum Model (PCM) at DFT/B3LYP/6-311+G(d) level. The static and dynamic (1064 nm) molecular parameters as the dipole moment, linear polarizability, first and second hyperpolarizabilities were studied as function of the solvent dielectric constant value. The geometrical behavior as the chemical bond angles, torsion angles, and partial charges distribution of the compounds were studied, including calculations of gap energies in various solvents. The obtained results revealed that the substituent change of CH3 (4MP3P) to NO2 (4NP3P) benefits the nonlinear optical properties of the compounds in the presence of the solvent media, the absolute values of the parallel first hyperpolarizability were the ones that present the greater variation.

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Vander Hoogerstraete, Tom, Ernesto Rezende Souza, Bieke Onghena, Dipanjan Banerjee, and Koen Binnemans. "Mechanism for Solvent Extraction of Lanthanides from Chloride Media by Basic Extractants." Journal of Solution Chemistry 47, no. 8 (2018): 1351–72. http://dx.doi.org/10.1007/s10953-018-0782-4.

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Svartman, Esther Lea, José Alberto Caram, María Virginia Mirífico, and Enrique Julio Vasini. "Electrochemistry of 1,2,5-thiadiazole 1,1-dioxide derivatives with 3,4 substituents presenting separated, connected, and fused Pi-systems." Canadian Journal of Chemistry 77, no. 4 (1999): 511–17. http://dx.doi.org/10.1139/v99-051.

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The voltammetric electroreduction properties of 1,2,5-thiadiazole 1,1-dioxide derivatives with different 3,4 substituents have been investigated in aprotic (mainly acetonitrile) solvent solution. The 3,4 substituents, selected according to the characteristics of their π-system, were phenanthro-9,10 (connected π-system) and acenaphtho-1,2 (fused π-system). New measurements are also presented for 3,4-diphenyl (separated π-systems). The basic properties of the substrates were investigated through voltammetry in acidic acetonitrile solutions. The substrates were more easily electroreduced (between -0.6 and -1.0 V vs. Ag/Ag+, acetonitrile solvent) than the parent (non-1,1-dioxide) heterocycles (which are electroreduced at ca. -2.5 V). They were also more easily electroreduced (by ca. 0.4 V) than the corresponding diketones (benzil, 9,10-phenanthrenequinone, and acenaphthenequinone). The influence on voltammetric behavior of the electron-withdrawing properties of the 1,2,5-thiadiazole 1,1-dioxide ring and that of the structure of the molecules was analyzed in light of previous structural studies by X-ray crystallography and theoretical chemistry calculations. Bulk electrolysis experiments in acidic acetonitrile solutions of the phenanthro[9,10-c] derivative produced its previously unreported dihydrogenated derivative (thiadiazoline), which oxidizes easily. Infrared spectroscopy data suggested that the structure of this compound differs from that of 3,4-diphenyl-1,2,5-thiadiazoline 1,1-dioxide.Key words: organic electrochemistry, 1,2,5- thiadiazoles, structure-reactivity relations.

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Tran, Chau B., Quoc Bao Le, and Rudolf Kiefer. "Linear Actuation of Dielectrophoretic Formed Multi-Walled Carbon Nanotube Fiber with Carbide-Derived Carbon in Polar Aprotic and Polar Protic Solvents." Materials 18, no. 14 (2025): 3254. https://doi.org/10.3390/ma18143254.

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Carbon nanotube (CNT) fiber research focuses on developing functional fabrics with dual or multifunctional capabilities. This study investigates CNT fibers fabricated via dielectrophoresis (DEP) with the incorporation of 10 wt.% carbide-derived carbon (CDC), referred to as CNTCDC fibers. The linear actuation behavior of the CNT and the CNTCDC fibers is compared using identical electrolyte concentrations in both a polar aprotic solvent (propylene carbonate, PC) and a polar protic solvent (aqueous solution, aq). Electromechanical deformation (EMD) is studied through cyclic voltammetry and chronoamperometry. The CNTCDC fiber outperformed the pristine CNT fiber, exhibiting primary expansion during discharge in PC (stress: 1.64 kPa, strain: 0.1%) and during charge in water (stress: 1.32 kPa, strain: 0.047%). By contrast, the pristine CNT fibers showed mixed actuation responses in both solvents, resulting in diminished net stress and strain. Chronopotentiometric measurements indicated that the CNTCDC fibers achieved their highest specific capacitance in aqueous media, reaching 223 ± 17 F g−1 at ±0.8 A g−1, with a capacity retention of 94.2% at ±32 A g−1. Fundamental characterization techniques, including scanning electron microcopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and Raman spectroscopy, are employed to analyze fiber morphology and composition. The dual functionality of CNTCDC fibers, as both actuators and energy storage elements, is demonstrated.

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Arshad, Mahwish, Nasir Rasool, Muhammad Usman Qamar, Syed Adnan Ali Shah, and 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, no. 12 (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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Nagani, Afzal, Moksh Shah, Salman Patel, and M. R. Yadav. "Sustainable synthesis of piperazine analogs using varied energy sources in the petasis reaction: A green chemistry perspective." INDIAN JOURNAL OF HETEROCYCLIC CHEMISTRY 34, no. 03 (2024): 399. http://dx.doi.org/10.59467/ijhc.2024.34.399.

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The Petasis reaction between substituted boronic acids (1a-c), N-Boc-piperazine, and glyoxylic acid in the conventional method of synthesis needs continuous refluxing for 16 h in a solvent like acetonitrile (ACN) to obtain the products. Using the same reactants, the source of energy was changed to microwave irradiation, ultrasonication, or mechanical energy (Trituration) to obtain good yields of the products consuming much less energy and time. Apart from the use of different sources of energy, the solvents as the media of the reactants were also changed. In microwave synthesis, more than 95% yield was obtained for the products in the presence of ACN/dichloromethane as solvents. In the sonication method, the yield ranged from 76 to 98% while in the trituration method, the yield decreased to 76-82% in the presence of various polar protic/aprotic solvents. Microwave irradiation or ultrasonication provides good alternatives to refluxing the reaction mixture continuously for a long time.. KEYWORDS :Microwave synthesis, Multicomponent reactions, Petasis reaction, Sonication, Trituration.

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Langton, Matthew J., and Paul D. Beer. "Nitrate anion templated synthesis of a [2]catenane for nitrate recognition in organic–aqueous solvent media." Chem. Commun. 50, no. 60 (2014): 8124–27. http://dx.doi.org/10.1039/c4cc03200d.

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The first example of a catenane synthesised using a nitrate anion template is demonstrated. The resulting interlocked host is capable of selectively recognising nitrate over a range of more basic oxoanions in a competitive organic–aqueous solvent mixture.

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Fernández-Bautista, Marcos, Sergio Martínez-Gómez, Sandra Rivas, José Luis Alonso, and Juan Carlos Parajó. "Advances on Cellulose Manufacture in Biphasic Reaction Media." International Journal of Molecular Sciences 24, no. 15 (2023): 12404. http://dx.doi.org/10.3390/ijms241512404.

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Cellulose is produced industrially by the kraft and sulfite processes. The evolution of these technologies in biorefineries is driven by the need to obtain greater added value through the efficient use of raw materials and energy. In this field, organosolv technologies (and within them, those using liquid phases made up of water and one partly miscible organic solvent, known as “biphasic fractionation” in reference to the number of liquid phases) represent an alternative that is receiving increasing interest. This study considers basic aspects of the composition of lignocellulosic materials, describes the fundamentals of industrial cellulose pulp production processes, introduces the organosolv methods, and comprehensively reviews published results on organosolv fractionation based on the use of media containing water and an immiscible solvent (1-butanol, 1-pentanol or 2-methyltetrahydrofuran). Special attention is devoted to aspects related to cellulose recovery and fractionation selectivity, measured through the amount and composition of the treated solids.

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Mohammed, Sawsan A. M., and Sally D. Maan. "The Effect of Asphaltene on the Stability of Iraqi Water in Crude Oil Emulsions." Iraqi Journal of Chemical and Petroleum Engineering 17, no. 2 (2016): 37–45. http://dx.doi.org/10.31699/ijcpe.2016.2.5.

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In the present work, asphaltenes and resins separated from emulsion samples collected from two Iraqi oil wells, Nafut Kana (Nk) and Basrah were used to study the emulsion stability. The effect of oil resins to asphaltene (R/A) ratio, pH of the aqueous phase, addition of paraffinic solvent (n-heptane), aromatic solvent (toluene), and blend of both (heptol) in various proportions on the stability of emulsions had been investigated. The conditions of experiments were specified as an agitation speed of 1000 rpm for 30 minutes, heating at 50 °C, and water content of 30%. The results showed that as the R/A ratio increases, the emulsion will be unstable and the amount of water separated from emulsion increases. It was noticed that the emulsion of Nk crude oil became more stable at basic pH range, and reached to completely stabilized emulsion at pH=12. Whereas Basrah emulsion was stable in both acidic and basic pH ranges. Results indicated that toluene gave a good solubility for asphaltene, and a higher water separation for both crude oil emulsions. A mathematical model to determine the kinetic constants that characterize the coalescence in the emulsions was also developed.

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Santos, Kryslaine M. A., Simone J. Canhaci, Rafael F. Perez, and Marco A. Fraga. "Hexoses Biorefinery: Driving Glucose Dehydration over Sulfonic Polymer and Hybrid Acid Catalysts." Reactions 6, no. 2 (2025): 26. https://doi.org/10.3390/reactions6020026.

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Glucose is the most abundant monosaccharide as it is the primary unit of cellulose and starch, which are the more relevant feedstocks for biorefineries. Dehydration of glucose can lead to anhydroglucoses, whose interest has been increasing due to its potential industrial use. Commercial sulfonic polymer resins and a synthesized organic–inorganic mesoporous material were taken as Brønsted acid catalysts. High hexose conversion (up to 98%) and selectivity to anhydroglucoses (~80%) could be reached, turning this process into an alternative route to carbohydrate pyrolysis that presents an energy-intensive downstream. Hexose conversion to anhydroglucoses was related to the amount of acid sites, and the removal of one molecule of water from hexoses to produce anhydroglucoses was found as the preferential dehydration route over a bare Brønsted acid catalyst in anhydrous polar aprotic solvent (DMF) at mild conditions. Product distribution changed dramatically upon catalyst deactivation with HMF and fructose emerging as relevant products. It was suggested that an additional Lewis surface is produced during the deactivation process, probably arising from the formation of insoluble high molecular weight compounds in acidic media.

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Debashree, Singh, Chatterjee Abhik, Chall Sayantani, et al. "Spectroscopic study of photo-physical parameters of dyes in different solvents environment." Education in Chemical Science and Technology Vol. 12, Feb 2023 (2023): 120–29. https://doi.org/10.5281/zenodo.7777314.

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Department of Chemistry, Haldia Institute of Technology, Haldia, West Bengal, India. Department of Chemistry, Raigang University, Uttar Dinajpur, West Bengal, India. Email id*- pijuskhatua@gmail.com (corresponding Author) Email id*- abhikchemistry@gmail.com (corresponding Author) Surrounding condition has a great role on the spectral characteristics of photosensitive dyes. Solvents having different characteristic and influence in the change of both ground and excited state of photo sensitive dyes as solvent molecules interact with the probe molecule in different way in its microenvironment[1-5]. Photo chemical and photo physical phenomenon are applied in our everyday life like paints, highway hoardings, light fastness in dying fiber and in determining the surfactant characteristics etc. Low energy ground state and high energy exited state electronic transition is the cause of spectroscopic transition. The characteristics of spectroscopic transitions also affected by the free energy changes or interaction among dye and solvents [6-12] molecules. Surface mole fraction of solvents around probe molecules differ from the bulk causes change in spectroscopic properties in mixture of different solvents. Different electronic state arises due to difference of density of electrons [13-18] in surrounding microenvironment of solvent. On the other hand the fluorescence emission spectra of many fluorophores are too much sensitive to the solvent polarity which also responsible for bathochromic spectral shift towards higher wavelength and hypsochromic shifts towards lower wavelength.  In general, better stability of dye molecules in the higher energy state due to enhance polar [19]characteristic in compare to the lower energy state andwith increase in solvent polarity indicating lowering the energy of transition through red shift.  This work presents solvent effect studies with a number of photo sensitive dyes [11,12] in microenvironment of aprotic and protic medium. From various interaction parameter studies and analysis, it has been found that at exited state dye interact with micro environment either through special intermolecular hydrogen bonding or polar-polar interaction [20-22] with media in case of every dyes.

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Hillman, A. Robert, Karl S. Ryder, Hani K. Ismail, Asuman Unal, and Annelies Voorhaar. "Fundamental aspects of electrochemically controlled wetting of nanoscale composite materials." Faraday Discussions 199 (2017): 75–99. http://dx.doi.org/10.1039/c7fd00060j.

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Electroactive films based on conducting polymers have numerous potential applications, but practical devices frequently require a combination of properties not met by a single component. This has prompted an extension to composite materials, notably those in which particulates are immobilised within a polymer film. Irrespective of the polymer and the intended application, film wetting is important: by various means, it facilitates transport processes – of electronic charge, charge-balancing counter ions (“dopant”) and analyte/reactant molecules – and motion of polymer segments. While film solvent content and transfer have been widely studied for pristine polymer films exposed to molecular solvents, extension to non-conventional solvents (such as ionic liquids) or to composite films has been given much less attention. Here we consider such cases based on polyaniline films. We explore two factors, the nature of the electrolyte (solvent and film-permeating ions) and the effect of introducing particulate species into the film. In the first instance, we compare film behaviours when exposed to a conventional protic solvent (water) with an aprotic ionic liquid (Ethaline) and the intermediate case of a protic ionic liquid (Oxaline). Secondly, we explore the effect of inclusion of physically diverse particulates: multi-walled carbon nanotubes, graphite or molybdenum dioxide. We use electrochemistry to control and monitor the film redox state and change therein, and acoustic wave measurements to diagnose rheologicallyvs.gravimetrically determined response. The outcomes provide insights of relevance to future practical applications, including charge/discharge rates and cycle life for energy storage devices, “salt” transfer in water purification technologies, and the extent of film “memory” of previous environments when sequentially exposed to different media.

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Shah, Pervaiz Akhtar, Haroon Khalid Syed, Abdul Rehman Sohail, et al. "Comparison of solvent evaporation and ultrasonicassisted production methods in the development of nimesulide nanosponges and their characterization." Tropical Journal of Pharmaceutical Research 21, no. 6 (2022): 1139–45. http://dx.doi.org/10.4314/tjpr.v21i6.1.

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Purpose: To compare solvent evaporation and ultrasonic assisted synthesis in preparation of nimesulide nanosponges using polyvinyl-alcohol and Eudragit L100 as a polymer/copolymer and dichloromethane as a cross linker.Methods: Twelve formulations of nimesulide were prepared, six with each method by varying the ratios of both polymer and co-polymer. The resulting nanosponges were evaluated characterized by preformulation studies, production yield (%), differential scanning calorimeter, x-ray diffraction, Fourier transformation infrared spectroscopy, scanning electron microscopy, entrapment efficiency (%), actual drug content (%) and in-vitro dissolution studies.Results: The results revealed that the formulation with high amounts of co-polymer in both methods showed crystalline structures with enhanced dissolution rates in basic media. Drug entrapment was higher for products prepared by solvent evaporation method (74 %) than that prepared by ultrasonic assisted method (61 %). This correlates with the enhanced dissolution rates for products by solvent evaporation method and increased solubility due to drug-polymer complex formation.Conclusion: Formulations made by solvent evaporation method demonstrate higher production yield and drug entrapment. However, both methods exhibit enhanced dissolution rates in basic medium generally as well as other characteristics that are comparable to nanosponges reported in the literature with regard to their comb like structure.

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