Articles de revues : « Solvent system »

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Raksajati, Anggit, Minh Ho et Dianne Wiley. « Solvent Development for Post-Combustion CO2 Capture : Recent Development and Opportunities ». MATEC Web of Conferences 156 (2018) : 03015. http://dx.doi.org/10.1051/matecconf/201815603015.

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Chemical absorption is widely regarded as the most promising technology for post-combustion CO2 capture from large industrial emission sources with CO2 separation from natural gas using aqueous amine solvent system having been applied since the 1930s. The use of monoethanolamine (MEA) in CO2 absorption system possesses several drawbacks, such as high regeneration energy, high solvent loss, and high corrosion tendency. Various solvents have been developed for post-combustion CO2 capture application including the development of aqueous solvents and phase-change solvents. Some of these alternate solvents have been reported to have better solvent properties, which could improve the CO2 absorption system performance. This paper reviews key parameters involved in the design improvement of several chemical absorption process systems. In addition, some novel solvent systems are also discussed, for example encapsulated solvents systems. Some of the key solvent parameters that affect the capture performance, such as heat of reaction, absorption rate, solvent working capacity, solvent concentration, and solvent stability, are discussed in this paper, particularly in relation to the economic viability of the capture process. In addition, some guidelines for the future solvent development are discussed.

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HR, Kuyakhi. « Estimation of Viscosity of the N-Alkane (C1-C 4) in Bitumen System Using Adaptive Neuro-Fuzzy Interference System (ANFIS) ». Petroleum & ; Petrochemical Engineering Journal 4, n^o 3 (2020) : 1–5. http://dx.doi.org/10.23880/ppej-16000233.

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One of the important mechanisms in solvent-aided thermal recovery processes is viscosity reduction. Light n-alkane hydrocarbons are among the potential solvents for solvent-aided thermal recovery processes. In this study, the viscosity of C1- C4 n-alkanes in bitumen was investigated. Adaptive neuro-fuzzy interference system (ANFIS) was used for this aim. The result obtained by the ANFIS model analyzed with the statistical parameters (i.e., MSE, MEAE, MAAE, and R2) and graphical methods. Results show that the ANFIS has high capability to the prediction of solvent/bitumen mixture viscosity.

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Tan, Zhe, Yuhan Liu et Bo Huang. « A highly efficient three-solvent methodology for separating colloidal nanoparticles ». Nanoscale 14, n^o 14 (2022) : 5482–87. http://dx.doi.org/10.1039/d2nr00495j.

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The centrifugation mechanism in three-solvent systems was proposed, including film formation and film fusion. A novel three-solvent system with low-toxicity solvents and high separation efficiency was established for separating nanomaterials.

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Watanabe, Kei, Taiki Nakamura, Byoung Suhk Kim et Ick Soo Kim. « Preparation and Characteristics of Electrospun Polypropylene Fibers : Effect of Organic Solvents ». Advanced Materials Research 175-176 (janvier 2011) : 337–40. http://dx.doi.org/10.4028/www.scientific.net/amr.175-176.337.

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Recently, we have reported that syndiotactic polypropylene (sPP) fibrous membrane could be successfully prepared from a multi component solvent system via electrospinning at room temperature. The base solvent of multi component solvent system was cyclohexane. As demonstrated SEM images, the formation of rough surface morphologies and the microholes on electrospun sPP fibers were observed. In this study, we successfully prepared sPP nanofiber webs from a different base solvent was decalin. SEM study demonstrated that the sPP nanofibers prepared from decalin based solvent had smoother surface morphology unlike cyclohexane based solvent, suggesting that the surface morphology of electrospun sPP nanofibers depended on the boiling point of each solvent used. Moreover, to investigate the crystal and molecular structures of electrospun sPP fibers from a different solvent system (i.e., decalin and cyclohexane based solvents), WAXD and FT-IR analysis were carried out. The results showed that the different solvent systems caused the different surface morphologies but the crystal and molecular structure of the electrospun sPP fibers didn’t change.

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IGARI, Youichi. « Solvent recovery system. » Circuit Technology 6, n^o 3 (1991) : 192–99. http://dx.doi.org/10.5104/jiep1986.6.3_192.

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Liu, Lei-Gen, et Ji-Huan He. « Solvent evaporation in a binary solvent system for controllable fabrication of porous fibers by electrospinning ». Thermal Science 21, n^o 4 (2017) : 1821–25. http://dx.doi.org/10.2298/tsci160928074l.

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Solvent evaporation is used for fabrication of nanoporous fibers by electrospinning, where multiple solvents are used. Pore size and distribution can be con-trolled by the fractions of the spun solution. An experiment was carefully designed, where polysulfone and poly(lactic acid) were dissolved in a binary solvent of dichloromethane and dimethylacetamide, to reveal the controllable process for fabrication of nanoporous fibers.

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Sanders, Alyssa B., Jacob T. Zangaro, Nakoa K. Webber, Ryan P. Calhoun, Elizabeth A. Richards, Samuel L. Ricci, Hannah M. Work et al. « Optimization of Biocompatibility for a Hydrophilic Biological Molecule Encapsulation System ». Molecules 27, n^o 5 (27 février 2022) : 1572. http://dx.doi.org/10.3390/molecules27051572.

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Despite considerable advances in recent years, challenges in delivery and storage of biological drugs persist and may delay or prohibit their clinical application. Though nanoparticle-based approaches for small molecule drug encapsulation are mature, encapsulation of proteins remains problematic due to destabilization of the protein. Reverse micelles composed of decylmonoacyl glycerol (10MAG) and lauryldimethylamino-N-oxide (LDAO) in low-viscosity alkanes have been shown to preserve the structure and stability of a wide range of biological macromolecules. Here, we present a first step on developing this system as a future platform for storage and delivery of biological drugs by replacing the non-biocompatible alkane solvent with solvents currently used in small molecule delivery systems. Using a novel screening approach, we performed a comprehensive evaluation of the 10MAG/LDAO system using two preparation methods across seven biocompatible solvents with analysis of toxicity and encapsulation efficiency for each solvent. By using an inexpensive hydrophilic small molecule to test a wide range of conditions, we identify optimal solvent properties for further development. We validate the predictions from this screen with preliminary protein encapsulation tests. The insight provided lays the foundation for further development of this system toward long-term room-temperature storage of biologics or toward water-in-oil-in-water biologic delivery systems.

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Sun, Shanhu, Haobin Zhang, Jinjiang Xu, Shumin Wang, Hongfan Wang, Zhihui Yu, Lang Zhao, Chunhua Zhu et Jie Sun. « The competition between cocrystallization and separated crystallization based on crystallization from solution ». Journal of Applied Crystallography 52, n^o 4 (8 juillet 2019) : 769–76. http://dx.doi.org/10.1107/s1600576719008094.

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The competition between cocrystallization and separated crystallization in a solvent was explored via X-ray diffraction and high-performance liquid chromatography methods in different solvents and by considering the solvent evaporation rate. The results revealed that the solvent system and solvent evaporation rate can affect the nucleation order of the cocrystal and coformers in the solution. In fact, solubility tests in different solvents confirmed that the solubility plays a key role in the cocrystal formation process. Furthermore, the width of the metastable zone influenced the solute nucleation order and was a decisive factor in the cocrystal formation process when the solvent evaporation rate was varied. Cocrystals could therefore be obtained by adjusting the solvents and solvent evaporation rate. The preparation of kinetic 2,4,6,8,10,12-hexanitrohexaazaisowurtzitane–2,4,6-trinitrophenol cocrystals via rapid solvent evaporation proves the practicability of this theory.

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Cipta, Oktavianus Hendra, Anita Alni et Rukman Hertadi. « Molecular Dynamics Study of Candida rugosa Lipase in Water, Methanol, and Pyridinium Based Ionic Liquids ». Key Engineering Materials 874 (janvier 2021) : 88–95. http://dx.doi.org/10.4028/www.scientific.net/kem.874.88.

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The structure of Candida rugosa lipase can be affected by solvents used in the enzymatic reactions. Using molecular dynamics simulation as a tool to study the Candida rugosa lipase structure, we studied the effect of various solvent systems, such as water, water-methanol, and water-methanol-ionic liquid. These solvent systems have been chosen because lipase is able to function in both aqueous and non-aqueous medium. In this study, pyridinium (Py)-based ionic liquids were selected as co-solvent. The MD simulation was run for 50 nanoseconds for each solvent system at 328 K. In the case of water-methanol-ionic liquids solvent systems, the total number of the ionic liquids added were varied: 222, 444, and 888 molecules. Water was used as the reference solvent system. The structure of Candida rugosa lipase in water-methanol system significantly changed from the initial structure as indicated by the RMSD value, which was about 6.4 Å after 50 ns simulation. This value was relatively higher compared to the other water-methanol solvent system containing ionic liquid as co-solvent, which were 2.43 Å for 4Py-Br, 2.1 Å for 8Py-Br, 3.37 Å for 4Py-BF4 and 3.49 Å for 8Py-BF4 respectively. Further analysis by calculating the root mean square fluctuation (RMSF) of each lipase residue found that the presence of ionic liquids could reduce changes in the enzyme structure. This happened because the anion component of the ionic liquid interacts relatively more strongly with residues on the surface of the protein as compared to methanol, thereby lowering the possibility of methanol to come into contact with the protein.

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Tsukagoshi, Norihiko, et Rikizo Aono. « Entry into and Release of Solvents byEscherichia coli in an Organic-Aqueous Two-Liquid-Phase System and Substrate Specificity of the AcrAB-TolC Solvent-Extruding Pump ». Journal of Bacteriology 182, n^o 17 (1 septembre 2000) : 4803–10. http://dx.doi.org/10.1128/jb.182.17.4803-4810.2000.

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ABSTRACT Growth of Escherichia coli is inhibited upon exposure to a large volume of a harmful solvent, and there is an inverse correlation between the degree of inhibition and the logP OW of the solvent, whereP OW is the partition coefficient measured for the partition equilibrium established between the n-octanol and water phases. The AcrAB-TolC efflux pump system is involved in maintaining intrinsic solvent resistance. We inspected the solvent resistance of ΔacrAB and/or ΔtolC mutants in the presence of a large volume of solvent. Both mutants were hypersensitive to weakly harmful solvents, such as nonane (logP OW = 5.5). The ΔtolC mutant was more sensitive to nonane than the ΔacrAB mutant. The solvent entered the E. coli cells rapidly. Entry of solvents with a log P OW higher than 4.4 was retarded in the parent cells, and the intracellular levels of these solvents were maintained at low levels. The ΔtolC mutant accumulated n-nonane or decane (logP OW = 6.0) more abundantly than the parent or the ΔacrAB mutant. The AcrAB-TolC complex likely extrudes solvents with a log P OW in the range of 3.4 to 6.0 through a first-order reaction. The most favorable substrates for the efflux system were considered to be octane, heptane, and n-hexane.

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LIU, YANG, et KIAN-MENG LIM. « PARTICLE TRANSPORT ACROSS BI-FLUID INTERFACE USING ACOUSTIC RADIATION FORCE ». Modern Physics Letters B 24, n^o 13 (30 mai 2010) : 1397–400. http://dx.doi.org/10.1142/s0217984910023712.

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A bi-fluid micro-flow system is proposed for separating particles from its original solvent and re-diluting them into another solvent simultaneously. In this micro-flow system, two different miscible solvents flow parallel to each other through a 2-inlet-2-outlet micro-channel, where an acoustic standing wave is set up. Due to the differences in acoustic properties of these solvents, the pressure node of the acoustic wave is shifted from the middle line of the channel. Under the action of the acoustic radiation force, particles with positive ϕ-factors are extracted from their original solvent and re-suspended into the other solvent, wherein the pressure node resides. Particles suspended in the new solvent are collected at one of the two outlets downstream. Experiments were conducted on a prototype using two aqueous solutions: deionized water and 40% glycerin aqueous solution with polystyrene micro-particles. The results show that under the action of the acoustic standing wave, most of the particles were successfully transported from its original solvent to the other solvent and collected at the outlet.

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Lai, Chin-Hung, Chia-Chin Chang, Yi-Lin Weng et Ta-Hsien Chuang. « Synthesis, Experimental and Density Functional Theory (DFT) Studies on Solubility of Camptothecin Derivatives ». Molecules 23, n^o 12 (1 décembre 2018) : 3170. http://dx.doi.org/10.3390/molecules23123170.

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Two camptothecin derivatives, 10-cyclohexyl-7-methyl-20(S)-camptothecin and 7-methyl-10-morpholino-20(S)-camptothecin, were synthesized and their differences in solubility were investigated using four chosen solvent systems. Based on our results, 10-cyclohexyl-7-methyl-20(S)-camptothecin exhibited higher solubilities than 7-methyl-10-morpholino-20(S)-camptothecin in polar aprotic solvents. However, these two camptothecin derivatives did not exhibit apparent differences in solubility between 5% dimethyl sulfoxide (DMSO)/95% normal saline co-solvent system and 5% dimethylacetamide (DMAC)/95% normal saline co-solvent system. To rationalize their differences in solubility, we also tried to perform a DFT-B3LYP study to investigate their interaction with one water molecule.

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Li, Xian-Zhi, Li Zhang et Keith Poole. « Role of the Multidrug Efflux Systems ofPseudomonas aeruginosa in Organic Solvent Tolerance ». Journal of Bacteriology 180, n^o 11 (1 juin 1998) : 2987–91. http://dx.doi.org/10.1128/jb.180.11.2987-2991.1998.

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ABSTRACT Multidrug efflux pumps with a broad substrate specificity make a major contribution to intrinsic and acquired multiple antibiotic resistance in Pseudomonas aeruginosa. Using genetically defined efflux pump mutants, we investigated the involvement of the three known efflux systems, MexA-MexB-OprM, MexC-MexD-OprJ, and MexE-MexF-OprN, in organic solvent tolerance in this organism. Our results showed that all three systems are capable of providing some level of tolerance to organic solvents such as n-hexane andp-xylene. Expression of MexAB-OprM was correlated with the highest levels of tolerance, and indeed, this efflux system was a major contributor to the intrinsic solvent tolerance of P. aeruginosa. Intrinsic organic solvent tolerance was compromised by a protonophore, indicating that it is substantially energy dependent. These data suggest that the efflux of organic solvents is a factor in the tolerance of P. aeruginosa to these compounds and that the multidrug efflux systems of this organism can accommodate organic solvents, as well as antibiotics.

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Nyquist, Richard A., Sam E. Settineri et Davin A. Luoma. « Infrared Study of Benzaldehyde and 4-Substituted Benzaldehydes in Carbon Tetrachloride and/or Chloroform Solutions : The Carbonyl Group ». Applied Spectroscopy 45, n^o 10 (décembre 1991) : 1641–48. http://dx.doi.org/10.1366/0003702914335157.

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The carbonyl stretching mode of 4- x-benzaldehydes increases in frequency as the mole % CHCl3/CCl4 decreases and as the value of σP− or σRO for the 4- x atom or group increases. Other functional groups such as OH, NO2 and CN are also affected by interaction with the CHCl3 and/or CCl4 solvent system. Other solvents may interact differently with each functional group so that, say, vC=O vs. σP−, σRO, or solvent acceptor numbers (AN) may not correlate in a uniform manner in all solute/solvent systems.

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Obek, Christine Ann, Foster Kofi Ayittey et Agus Saptoro. « Improved process modifications of aqueous ammonia-based CO2 capture system ». MATEC Web of Conferences 268 (2019) : 02004. http://dx.doi.org/10.1051/matecconf/201926802004.

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Extensive research works on CO2 capture process using MEA have been carried out and showed promising results. Nevertheless, it has been acknowledged that the use of MEA is associated with high cost, solvent degradation issues and corrosion. The issues above have motivated researchers to explore and test other potential solvents such as aqueous ammonia (NH3). As result, NH3 based CO2 capture systems have recently attracted much attention as an alternative to MEA based counterparts. Despite their encouraging applications, high volatility of NH3 raise concerns on the energy requirement related to the solvent recovery. Consequently, energy efficient NH3 based CO2 capture systems by modifying the process is desirable. This study, therefore, aims to propose and evaluate three different stand-alone process configurations of absorption-desorption processes in a NH3-based system and compare them with the traditional absorption-desorption system in respect to total energy consumption. These modifications include Rich Solvent Split (RSS), Lean Vapor Compression (LVC), and Rich Vapor Compression (RVC). Results indicate that among these three proposed process modifications, LVC led to the highest reboiler energy savings of 38.3% and total energy savings of 34.5% compared to NH3 based conventional configuration. These findings can serve as essential recommendations for further studies on and large-scale implementations of aqueous NH3 as a better solvent.

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Ugwu, K. E., et P. O. Ukoha. « Impacts of Extraction Methods and Solvent Systems in the Assessment of Toxic Organic Compounds in a Solid Matrix ». Asian Journal of Chemistry and Pharmaceutical Sciences 1, n^o 1 (21 novembre 2016) : 23. http://dx.doi.org/10.18311/ajcps/2016/7523.

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Polycyclic Aromatic Hydrocarbons (PAHs) are among the listed persistent organic compounds (POP) which are pollutants of environmental concern due to their toxicity. This study evaluated soxhlet and ultrasonic extraction methods using a three-solvent system (acetone+dichloromethane+n-hexane) in order to compare the ability of the techniques to extract selected PAHs in raw coals collected from a coal mine in Okobo-Enjema, Nigeria. Then, binary solvent mixtures consisting of acetone+dichloromethane; dichloromethane+n-hexane; and acetone+n-hexane, were compared with the ternary solvent system for their ability to extract the target PAHs by soxhlet extraction method. The extracts were quantitatively analysed for sixteen PAHs using Gas Chromatography-Mass Spectrometer (GC-MS). Sonication extraction method extracted higher number of PAHs, required fewer amount of solvents, shorter time of extraction and less energy consumption compared to soxhlet extraction, which extracted higher amount of the target PAHs. The total amount of PAHs determined ranged from 0.02 mg/kg to 0.20 mg/kg in the various solvents' mixtures. The ternary mixture extracted larger quantities of the target toxic PAHs. This report will assist in the choice of analytical methods and solvent systems for environmental studies.

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Chowdhury, Somnath, Prajna Mukherjee, Monoj Das et Bikash C. Gupta. « Formation of charge transfer complex between metalloporphyrins and aromatic solvents in tetrahydrofuran media : A density functional study ». Journal of Porphyrins and Phthalocyanines 23, n^o 10 (octobre 2019) : 1149–57. http://dx.doi.org/10.1142/s1088424619501529.

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We have investigated the possible formation of charge transfer (CT) complexes of metallotetraphenylporphyrins (MTPhP with M = Mn, Fe, Co, Ni and Cu) and metallooctaethylporphyrins (MOEtP with M = Mn, Fe, Co, Ni, Cu and Zn) with the aromatic solvents, namely benzene, chlorobenzene, benzonitrile and toluene, respectively, in the tetrahydrofuran (THF) media. We have carried out energy minimization calculations of the hybrid systems (metalloporphyrins and aromatic solvents) in 1:1 and 1:2 stoichiometry in presence of THF media. We have analyzed the role of metal present in the metalloporphyrin in the formation of complexes for both 1:1 and 1:2 stoichiometry. Our analysis reveals that the MTPhP-solvent hybrid system is more stable compared to the MOEtP-solvent hybrid system.

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El Seoud, Omar A., Shirley Possidonio et Naved I. Malek. « Solvatochromism in Solvent Mixtures : A Practical Solution for a Complex Problem ». Liquids 4, n^o 1 (3 janvier 2024) : 73–94. http://dx.doi.org/10.3390/liquids4010003.

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Many reactions are carried out in solvent mixtures, mainly because of practical reasons. For example, E2 eliminations are favored over SN2 substitutions in aqueous organic solvents because the bases are desolvated. This example raises the question: how do we chose binary solvents to favor reaction outcomes? This important question is deceptively simple because it requires that we understand the details of all interactions within the system. Solvatochromism (solvent-dependent color change of a substance) has contributed a great deal to answer this difficult question, because it gives information on the interactions between solvents, solute-solvent, and presumably transition state-solvent. This wealth of information is achieved by simple spectroscopic measurements of selected (solvatochromic) substances, or probes. An important outcome of solvatochromism is that the probe solvation layer composition is almost always different from that of bulk mixed solvent. In principle, this difference can be exploited to “tune” the composition of solvent mixture to favor the reaction outcome. This minireview addresses the use of solvatochromic probes to quantify solute-solvent interactions, leading to a better understanding of the complex effects of solvent mixtures on chemical phenomena. Because of their extensive use in chemistry, we focus on binary mixtures containing protic-, and protic-dipolar aprotic solvents.

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Lang, Jinyan, Na Wang, Xinhui Wang, Yili Wang, Guorong Chen et Heng Zhang. « Applications of the Hansen solubility parameter for cellulose ». BioResources 16, n^o 4 (9 septembre 2021) : 7112–21. http://dx.doi.org/10.15376/biores.16.4.7112-7121.

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Based on the solubility parameter theory, the Hansen solubility parameters of various solvents were calculated and compared to predict the solubility of cellulose in various solvents, which illustrates the feasibility of Hansen solubility parameters to predict the solubility of cellulose in solvents. This paper aims to make a more accurate prediction in advance when finding suitable cellulose solvent system, and then to reduce the burden of cellulose solvent selection.

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Alade, Olalekan S., Dhafer A. Al Shehri, Mohamed Mahmoud, Samuel Olusegun, Lateef Owolabi Lawal, Muhammad Shahzad Kamal et Ayman Al-Nakhli. « Viscosity models for bitumen–solvent mixtures ». Journal of Petroleum Exploration and Production Technology 11, n^o 3 (22 février 2021) : 1505–20. http://dx.doi.org/10.1007/s13202-021-01101-9.

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AbstractViscosity is the resistance of a material to continuous deformation exerted by shear force. High viscosity, which is sometimes greater than 1 million mPa s, at the initial reservoir conditions, is a major challenge to recovery, production, and transportation of bitumen. Addition of organic solvents or diluents with bitumen leads to significant viscosity reduction and forms the basis for the steam/solvent-assisted recovery methods of extra-heavy oil and bitumen. Therefore, modeling and predicting viscosity of bitumen–solvent mixture has become an important step in the development of solvent-assisted system. The aim of this article is to present a concise survey of the various viscosity models that have been proposed to predict the viscosity of bitumen–solvent mixtures, and make comparative discussion on their applicability. Available reports revealed that the accuracy of a model to predict the viscosity of bitumen–solvent mixtures depends on various factors including the type and concentration of solvents, and the properties of the bitumen. Thus, no model has been found to have absolute capability to predict the viscosity for all mixtures. Therefore, there is room for further improvement on the viscosity modeling of bitumen–solvent system for wider applications.

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Cysewski, Piotr, Tomasz Jeliński et Maciej Przybyłek. « Experimental and Theoretical Insights into the Intermolecular Interactions in Saturated Systems of Dapsone in Conventional and Deep Eutectic Solvents ». Molecules 29, n^o 8 (11 avril 2024) : 1743. http://dx.doi.org/10.3390/molecules29081743.

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Solubility is not only a crucial physicochemical property for laboratory practice but also provides valuable insight into the mechanism of saturated system organization, as a measure of the interplay between various intermolecular interactions. The importance of these data cannot be overstated, particularly when dealing with active pharmaceutical ingredients (APIs), such as dapsone. It is a commonly used anti-inflammatory and antimicrobial agent. However, its low solubility hampers its efficient applications. In this project, deep eutectic solvents (DESs) were used as solubilizing agents for dapsone as an alternative to traditional solvents. DESs were composed of choline chloride and one of six polyols. Additionally, water–DES mixtures were studied as a type of ternary solvents. The solubility of dapsone in these systems was determined spectrophotometrically. This study also analyzed the intermolecular interactions, not only in the studied eutectic systems, but also in a wide range of systems found in the literature, determined using the COSMO-RS framework. The intermolecular interactions were quantified as affinity values, which correspond to the Gibbs free energy of pair formation of dapsone molecules with constituents of regular solvents and choline chloride-based deep eutectic solvents. The patterns of solute–solute, solute–solvent, and solvent–solvent interactions that affect solubility were recognized using Orange data mining software (version 3.36.2). Finally, the computed affinity values were used to provide useful descriptors for machine learning purposes. The impact of intermolecular interactions on dapsone solubility in neat solvents, binary organic solvent mixtures, and deep eutectic solvents was analyzed and highlighted, underscoring the crucial role of dapsone self-association and providing valuable insights into complex solubility phenomena. Also the importance of solvent–solvent diversity was highlighted as a factor determining dapsone solubility. The Non-Linear Support Vector Regression (NuSVR) model, in conjunction with unique molecular descriptors, revealed exceptional predictive accuracy. Overall, this study underscores the potency of computed molecular characteristics and machine learning models in unraveling complex molecular interactions, thereby advancing our understanding of solubility phenomena within the scientific community.

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Nyamiati, Retno Dwi, Siti Nurkhamidah, Yeni Rahmawati et Wahyu Meka. « Kinetic and Thermodynamic Studies in Cellulose Acetate-Polybutylene Succinate(CA-PBS)/Single Solvent/Water System for Desalination Membrane ». Eksergi 20, n^o 1 (2 mars 2023) : 8. http://dx.doi.org/10.31315/e.v20i1.8820.

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The most important part of the membrane synthesis process so that it has the desired pores is the solidification process of the membrane, the process begins with a change from one liquid phase into two liquid phases (liquid-liquid demixing). At a certain period during demixing, the polymer-rich phase solidifies; thus, a dense membrane matrix is formed. Parameters that determine the mechanism of membrane formation are based on thermodynamics including phase separation of Solvent-Polymer-Non-solvent which is explained through a phase diagram (Flory-Huggins Theory). This study aims to determine the initial prediction of the formation of CA-PBS membranes with various solvents used and variations of non-solvents in the best system, which is proven by its characteristics and performance when applied to desalination membranes which include ternary diagrams using cloud point data, solubility parameters with Hansesn solubility, the solvent-non-solvent diffusivity using the Tyn Calus Equation approach and the morphological proofing of the membrane through SEM photos, and the performance of the resulting membrane through salt rejection and permeate flux. The results of the difference in solubility parameters are can be predicted that using DMF solvent on the CA-PBS membrane can reduce the pore size and eliminate voids and macrovoids in the membrane morphology.

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Yadav, Jyoti, Dan G. Dumitrescu, Thomas Kendall, Carmen Guguta et Swati A. Patel. « Effect of Solvent Composition on Solubility, Thermodynamics, Metastable Zone Width (MSZW) and Crystal Habit of L-Ascorbic Acid ». Crystals 12, n^o 12 (9 décembre 2022) : 1798. http://dx.doi.org/10.3390/cryst12121798.

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This work investigates the effect of different solvent systems on solubility, thermodynamics, metastable zone width (MSZW), and crystal habit of ascorbic acid, in order to help optimize its crystallization process. The solubility curves and metastable zone (MSZ) limits were determined experimentally using the polythermal method in pure solvents: water and alcohols (methanol/ethanol/isopropanol), as well as water-alcohol binary solvent systems. The solubility decreases with increasing alcohol composition for all solvent systems. The solubility data were well correlated using the Jouyban–Acree model as a function of two variables: temperature and solvent composition. The dissolution enthalpy (ΔHdiss), dissolution entropy (ΔSdiss), and Gibbs free energy (ΔGdiss) were determined using Van’t Hoff and Jouyban–Acree models. The thermodynamic properties increase with increasing alcohol composition. The lowest and highest values of enthalpy were obtained for water (20.52 kJ mol −1) and isopropanol (35.33 kJ mol−1), respectively. Pure alcohols as solvents widen the metastable zone width, indicating high supersaturation required for the nucleation. Crystal images captured during cooling crystallization in water confirm the cubic crystal habit formation, whereas increasing alcohol composition in the solvent system promotes preferential growth along one crystallographic axis, leading to elongated prism-shaped crystals in methanol and ethanol and needle-shaped crystals in isopropanol.

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Isken, Sonja, Antoine Derks, Petra F. G. Wolffs et Jan A. M. de Bont. « Effect of Organic Solvents on the Yield of Solvent-Tolerant Pseudomonas putida S12 ». Applied and Environmental Microbiology 65, n^o 6 (1 juin 1999) : 2631–35. http://dx.doi.org/10.1128/aem.65.6.2631-2635.1999.

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ABSTRACT Solvent-tolerant microorganisms are useful in biotransformations with whole cells in two-phase solvent-water systems. The results presented here describe the effects that organic solvents have on the growth of these organisms. The maximal growth rate of Pseudomonas putida S12, 0.8 h−1, was not affected by toluene in batch cultures, but in chemostat cultures the solvent decreased the maximal growth rate by nearly 50%. Toluene, ethylbenzene, propylbenzene, xylene, hexane, and cyclohexane reduced the biomass yield, and this effect depended on the concentration of the solvent in the bacterial membrane and not on its chemical structure. The dose response to solvents in terms of yield was linear up to an approximately 200 mM concentration of solvent in the bacterial membrane, both in the wild type and in a mutant lacking an active efflux system for toluene. Above this critical concentration the yield of the wild type remained constant at 0.2 g of protein/g of glucose with increasing concentrations of toluene. The reduction of the yield in the presence of solvents is due to a maintenance higher by a factor of three or four as well as to a decrease of the maximum growth yield by 33%. Therefore, energy-consuming adaptation processes as well as the uncoupling effect of the solvents reduce the yield of the tolerant cells.

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Gealh, Gustavo, Maynara L. A. Santos, Marcos L. Corazza, Adrián Bonilla-Petriciolet et Fernando A. P. Voll. « Lipase-Catalyzed Synthesis of Cetyl Palmitate in the Presence of n-Hexane and Ethyl Ether ». International Journal of Chemical Engineering 2024 (4 avril 2024) : 1–7. http://dx.doi.org/10.1155/2024/4796291.

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Cetyl palmitate was produced by the esterification of palmitic acid with cetyl alcohol using n-hexane and ethyl ether as solvents and a commercial lipase as a catalyst. The effect of solvents to reagents mass ratio (0.5 : 1–3 : 1), percentage of n-hexane in the solvent mixture (0–100%), and reaction temperature (25–55°C) on the reaction rate were evaluated for a fixed amount of enzyme (1 wt% related to the total mass of substrates) in an equimolar mixture of palmitic acid and cetyl alcohol. Temperature and n-hexane percentage in the solvent had positive effects on the reaction rate. The total solvent-to-reagent mass ratio showed a negative effect on the reaction rate when a solvent mixture rich in ethyl ether was used. The higher the concentration of n-hexane, the lower the effect of the mass ratio of solvents to reagents on the reaction rate. Although the amount of ethyl ether in the solvent mixture had a negative effect on the reaction rate, it had a positive effect on the solubility of the system, that is, the more ethyl ether in the mixture, the lower the solvent to reagents mass ratio required to ensure a homogeneous mixture. A ping-pong bi-bi mechanism-based model was proposed to represent the system kinetics and was well fitted to the experimental data.

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Aljuboori, Sahar Balkat, Nedaa Abdulhameed Abdulrahim, Shuhad Yassen et Heba Hashim Khaleel. « Organic Synthesis under Solvent-free Condition (Green Chemistry) : A Mini Literature Review ». Al-Rafidain Journal of Medical Sciences ( ISSN : 2789-3219 ) 3 (17 décembre 2022) : 109–15. http://dx.doi.org/10.54133/ajms.v3i.94.

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Solvents are important components in the pharmaceutical and chemical industries, and they are increasingly being used in catalytic reactions. Solvents have a significant influence on the kinetics and thermodynamics of reactions, and they can significantly change product selectivity. Solvents can influence product selectivity, conversion rates, and reaction rates. However, solvents have received a lot of attention in the field of green chemistry. This is due to the large amount of solvent that is frequently used in a process or formulation, particularly during the purification steps. However, neither the solvent nor the active ingredient in a formulation is directly responsible for the reaction product's composition. Because these characteristics have little bearing on how well or quickly the system in which the solvent is applied works, it appears unnecessary to use toxic, combustible, or environmentally hazardous solvents. However, the beneficial properties of the solvent required for the application are strongly linked to these unfortunate side effects of solvent use. Distillation can be used to recover and purify solvents because they are volatile; however, this process can produce unwanted air pollutants and be hazardous to workers during exposure. .

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Khanjar, Jassim Mohammed, et Elham Omidbakhsh Amiri. « Simulation and parametric analysis of natural gas sweetening process : a case study of Missan Oil Field in Iraq ». Oil & ; Gas Science and Technology – Revue d’IFP Energies nouvelles 76 (2021) : 53. http://dx.doi.org/10.2516/ogst/2021033.

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Gas sweetening is one of the important purification processes which is employed to remove acidic contaminants from natural gases prior to meet transport requirements and sale gas specifications. In this work, simulation and parametric studies of the natural gas processing plant of Missan Oil Company/Buzurgan Oil Field of Natural Gas Processing Plant (in Iraq) were considered. After simulation and validation of this plant, the effect of feed temperature and flow rate and solvent concentration were considered. Results show with increasing the feed temperature and flow rate, the amount of H2S and CO2 in the sweet gas stream increases. Then, in the next step, the effect of mixture solvents was studied. Sulfolane–MDEA and MDEA–MEA were selected as a physical–chemical mixture solvent and chemical mixture solvent, respectively. The simulation results show that the solvent price and reboiler duty and cooling duty can be reduced by using a mixture solvent. However, the amount of H2S and CO2 in the sweet gas can be affected by these solvents. The system by a chemical mixture solvent can better performance than other solvents.

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Synooka, O., K. R. Eberhardt et H. Hoppe. « Chlorine-free processed high performance organic solar cells ». RSC Adv. 4, n^o 32 (2014) : 16681–85. http://dx.doi.org/10.1039/c4ra01783h.

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In this work, we demonstrate the successful replacement of a chlorinated solvent system based on a 1 : 1 mixture of chlorobenzene and ortho-dichlorobenzene with the chlorine-free solvent xylene, resulting in chlorine-free processing with a small amount of diiodooctane additive. In fact, the overall power conversion efficiency is improved from 6.71% for the chlorinated solvents to 7.15% for the chlorine-free solvent m-xylene.

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Autenrieth, Caroline, et Robin Ghosh. « The Methoxylated, Highly Conjugated C40 Carotenoids, Spirilloxanthin and Anhydrorhodovibrin, Can Be Separated Using High Performance Liquid Chromatography with Safe and Environmentally Friendly Solvents ». Metabolites 9, n^o 2 (24 janvier 2019) : 20. http://dx.doi.org/10.3390/metabo9020020.

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High performance liquid chromatography (HPLC) is a frequently used technique in carotenoid research. So far, however, little attention has been paid to the fact that many of the organic solvents used in HPLC separation of highly apolar C40 carotenoids impose a significant threat to both health (especially for women) and the general laboratory environment. Here, we developed a solvent combination capable of allowing high-resolution HPLC separation of the C40 carotenoid, spirilloxanthin, and all of its biosynthetic precursors beginning with phytoene, using relatively safe, environmentally friendly solvents. We show that separation of spirilloxanthin and its precursors anhydrorhodovibrin and lycopene using modern ultra-high performance chromatography (UHPLC) poses particular problems for apolar carotenoid separation, due to the long residence times in the sample delivery system, which facilitates carotenoid aggregation. We resolved these problems by developing the solvent delivery combination acetone/acetonitrile/isopropanol/methanol (65/30/5/2 (v/v/v/v)), which allows excellent column separation using the safe isocratic solvent system methanol/tetrahydrofuran (98/2 (v/v)). We also demonstrate that the development strategy for optimizing a solvent system for carotenoid separation can be well-described by the use of the average dielectric constant of the total sample delivery solvent, and present a formal method for analysis of the efficiency of separation.

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Aliwarga, Lienda, Herri Susanto, Reynard Reynard et Agnes Veronica Victoria. « UNIFAC Model for Liquid-Liquid Phase Equilibrium of Penicillin G and 6-APA System ». Jurnal Kimia Valensi 5, n^o 2 (30 novembre 2019) : 185–93. http://dx.doi.org/10.15408/jkv.v5i2.9869.

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This study investigated the effect of pH and type of solvent on liquid-liquid phase equilibrium in the system of pure penicillin G and mixed penicillin G with 6-APA. Penicillin G extraction was carried out in a pH range of 2.0–5.0 at 4 oC using several types of solvents. The liquid-liquid phase equilibrium mathematical model is prepared assuming that a single stage of thermodynamic equilibrium occurs in a batch process of liquid-liquid extraction. The coefficient of activity was calculated by the UNIFAC method. From the experiment, it was found that the extraction process of penicillin G was strongly influenced by pH of the solution. The highest yield of extraction was achieved with different solvents in the two types of solution. For pure penicillin G system, the highest yields was obtained in n-butyl acetate solvent (95.51%) while for penicillin G mixture with 6-APA, it was obtained in methyl iso-butyl ketone solvent (92.6%). The UNIFAC model have been tested against five three-component liquid-liquid phase equilibrium systems at pH 2.0 and 2.5. It was able to estimate the concentration of penicillin G in the organic phase with a relatively average error between experiment and calculation of 8.32%

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Guerdouh, Amel, et 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 octobre 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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Ahmed, Abubakar S., Murtala Ahmed et Aliyu Bello. « Molecular Dynamics Simulation Study of the Diffusion of Carbon Dioxide in Heptane : Application in Natural Gas Cleaning ». Journal of Chemical Engineering and Industrial Biotechnology 9, n^o 2 (30 décembre 2023) : 48–57. http://dx.doi.org/10.15282/jceib.v9i2.9495.

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Using solvents to remove carbon dioxide is an effective way to purify natural gas. Diffusion of solute in solvent is key to natural gas purification. In this study, molecular dynamics (MD) simulations of the diffusion of carbon dioxide in heptane at different temperatures and pressures were performed to simulate the conditions of industrial purification process. The diffusion coefficients were measured in two different configurations; pure solvent and binary solute-solvent systems. The diffusion coefficients of the binary system were observed to be in the order of 10-9 m2/s. An increased temperature was observed to increase the diffusion coefficient of the carbon dioxide in heptane while an increase in pressure reduced the value of the diffusion coefficient. The diffusion coefficient was also observed to follow an Arrhenius-type relationship with respect to temperature. The activation energy of the system increased from 9.228 kJ/mol to 11.139 kJ/mol with pressure increase. A linear relationship was detected between the diffusion coefficient and the viscosity of the system and an increased viscosity of the system results in a decreased diffusion coefficient. The results of the research showed that carbon dioxide behavior in heptane offers the theoretical backing for the development of a new natural gas desulphurization solvent.

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Mu, Liwen, Yijun Shi, Long Chen, Tuo Ji, Ruixia Yuan, Huaiyuan Wang et Jiahua Zhu. « [N-Methyl-2-pyrrolidone][C1–C4 carboxylic acid] : a novel solvent system with exceptional lignin solubility ». Chemical Communications 51, n^o 70 (2015) : 13554–57. http://dx.doi.org/10.1039/c5cc04191k.

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Maheu, Maxime, François Champoux et Adrian Fuente. « Acute Vertigo in a Patient with Long-Term Organic Solvent Exposure : Importance of a Comprehensive Audio-Vestibular Test Battery ». Journal of the American Academy of Audiology 31, n^o 05 (mai 2020) : 363–68. http://dx.doi.org/10.3766/jaaa.19034.

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Abstract Background Ototoxicity induced by organic solvents has been identified in several groups of workers. Little is known, however, about the effects of organic solvents on the vestibular system. Purpose The aim of the study was to comprehensively assess the vestibular system and auditory functions in a worker exposed to organic solvents. Research Design Both behavioral and physiological auditory and vestibular evaluations were performed. Results No auditory-related findings associated with solvent exposure were found. The vestibulo-ocular reflex gain was abnormal for all semicircular canals with significant catch-up saccades, as measured by the video head impulse test. The cervical vestibular evoked myogenic potentials was absent in the right ear and small but replicable in the left ear. Ocular vestibular evoked myogenic potential were bilaterally absent. Conclusions The results suggest a case of vestibulotoxicity induced by a long history of organic solvent exposure. We suggest that solvent-exposed individuals should be evaluated with a comprehensive battery of auditory and vestibular tests.

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Norjmaa, Gantulga, Gregori Ujaque et Agustí Lledós. « Beyond Continuum Solvent Models in Computational Homogeneous Catalysis ». Topics in Catalysis 65, n^o 1-4 (16 novembre 2021) : 118–40. http://dx.doi.org/10.1007/s11244-021-01520-2.

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AbstractIn homogeneous catalysis solvent is an inherent part of the catalytic system. As such, it must be considered in the computational modeling. The most common approach to include solvent effects in quantum mechanical calculations is by means of continuum solvent models. When they are properly used, average solvent effects are efficiently captured, mainly those related with solvent polarity. However, neglecting atomistic description of solvent molecules has its limitations, and continuum solvent models all alone cannot be applied to whatever situation. In many cases, inclusion of explicit solvent molecules in the quantum mechanical description of the system is mandatory. The purpose of this article is to highlight through selected examples what are the reasons that urge to go beyond the continuum models to the employment of micro-solvated (cluster-continuum) of fully explicit solvent models, in this way setting the limits of continuum solvent models in computational homogeneous catalysis. These examples showcase that inclusion of solvent molecules in the calculation not only can improve the description of already known mechanisms but can yield new mechanistic views of a reaction. With the aim of systematizing the use of explicit solvent models, after discussing the success and limitations of continuum solvent models, issues related with solvent coordination and solvent dynamics, solvent effects in reactions involving small, charged species, as well as reactions in protic solvents and the role of solvent as reagent itself are successively considered.

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Havránková, Jitka, Zuzana Limpouchová et Karel Procházka. « Monte Carlo Study of Dilute Solutions of Heteroarm Star Copolymers in Solvents Differing in Thermodynamic Quality ». Collection of Czechoslovak Chemical Communications 70, n^o 11 (2005) : 1848–60. http://dx.doi.org/10.1135/cccc20051848.

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Lattice Monte Carlo simulations (an original modification of the Siepmann and Frenkel simulation variant) was used to study the conformational behavior of heteroarm star copolymers star-(polystyrene; polyisoprene), PS8PI8, in a common good solvent for both types of arms (tetrahydrofuran) and in selective θ-solvents for both types of arms (in cyclohexane, i.e., in θ-solvent for PS and in 1,4-dioxane, i.e. in θ-solvent for PI). Results of simulations were compared with experimental data published by Pispas et al. The coarse graining procedure was performed to match the experimental behavior of heteroarm stars in a good solvent. The computer simulations reproduce all decisive trends of the conformational behavior for both selective solvents. The quantitative agreement between experimental and simulated size characteristics is very good. Simulations yield very detailed information on the system at the molecular level and show that the incompatible arms significantly segregate in selective solvents.

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Choudhuri, Khokan, Arkalekha Mandal et Prasenjit Mal. « Aerial dioxygen activation vs. thiol–ene click reaction within a system ». Chemical Communications 54, n^o 30 (2018) : 3759–62. http://dx.doi.org/10.1039/c8cc01359d.

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By choosing appropriate reaction systems using solvents with additives or solvent free neat conditions, any one of the Markovnikov or anti-Markovnikov selective thiol–ene click (TEC) reactions and the synthesis of β-hydroxysulfides via aerial dioxygen activation could be achieved exclusively in excellent yields.

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Wang, Xiaohan, Keying Liu, Yifan Wang, Zhuoneng Huang et Xiaosan Wang. « Preparation of 2-Arachidonoylglycerol by Enzymatic Alcoholysis : Effects of Solvent and Water Activity on Acyl Migration ». Foods 11, n^o 20 (14 octobre 2022) : 3213. http://dx.doi.org/10.3390/foods11203213.

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Enzymatic alcoholysis was performed in an organic medium to synthesize 2-monoacylglycerol (2-MAG) rich in arachidonic acid. The results showed that solvent type and water activity (aw) significantly affected the 2-MAG yield. Under the optimum conditions, 33.58% 2-MAG was produced in the crude product in t-butanol system. Highly pure 2-MAG was obtained after two-stage extraction using 85% ethanol aqueous solution and hexane at first stage and dichloromethane and water at second stage. Isolated 2-MAG was used as substrate to investigate the effect of solvent type and aw on 2-MAG acyl migration in a lipase-inactivated system. The results indicated that non-polar solvents accelerated the acyl migration of 2-MAG, whereas isomerization was inhibited in polar solvent systems. The aw exhibited the strongest inhibition effect on 2-MAG isomerization at 0.97, but also affected the hydrolysis of glycerides and lipase selectivity.

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Chen, Xiaoqi, Lu Bai, Chengyu Li, Jia Tian, Haijun Zhou, Mengmeng Zhou, Jijun Xiao et Yantao Li. « Study on Recrystallization Process of Poly(DL-lactide)/Poly(ethylene glycol) Diblock Copolymer ». MATEC Web of Conferences 358 (2022) : 01063. http://dx.doi.org/10.1051/matecconf/202235801063.

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Poly (DL-lactide)/Poly (ethylene glycol) diblock copolymer is successfully synthesized with mPEG and DL-LA as main raw materials, and the residual monomers of the polymer were removed by recrystallization. FT-IR is used to characterize the structure of the polymer. Gas chromatography is used to determine the residual monomers and residual solvent of the polymer. The solubility of polymer in different solvents was determined, and the effect of different solvent systems on the removal of residual monomers in copolymer were discussed. The results showed that the Poly(DL-lactide)/Poly(ethylene glycol) diblock copolymer was recrystallized with acetone/ isopropyl ether solvent system has the best ability to remove residual monomers, and the residual monomers of the obtained polymer are less than 0.01 wt%, the total residual solvent is only 0.24 wt%, and the productivity is as high as 95.5 wt%.

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Vaškevičius, Mantas, Jurgita Kapočiūtė-Dzikienė et Liudas Šlepikas. « Prediction of Chromatography Conditions for Purification in Organic Synthesis Using Deep Learning ». Molecules 26, n^o 9 (23 avril 2021) : 2474. http://dx.doi.org/10.3390/molecules26092474.

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In this research, a process for developing normal-phase liquid chromatography solvent systems has been proposed. In contrast to the development of conditions via thin-layer chromatography (TLC), this process is based on the architecture of two hierarchically connected neural network-based components. Using a large database of reaction procedures allows those two components to perform an essential role in the machine-learning-based prediction of chromatographic purification conditions, i.e., solvents and the ratio between solvents. In our paper, we build two datasets and test various molecular vectorization approaches, such as extended-connectivity fingerprints, learned embedding, and auto-encoders along with different types of deep neural networks to demonstrate a novel method for modeling chromatographic solvent systems employing two neural networks in sequence. Afterward, we present our findings and provide insights on the most effective methods for solving prediction tasks. Our approach results in a system of two neural networks with long short-term memory (LSTM)-based auto-encoders, where the first predicts solvent labels (by reaching the classification accuracy of 0.950 ± 0.001) and in the case of two solvents, the second one predicts the ratio between two solvents (R2 metric equal to 0.982 ± 0.001). Our approach can be used as a guidance instrument in laboratories to accelerate scouting for suitable chromatography conditions.

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Mahadlek, Jongjan, et Thawatchai Phaechamud. « Metrodidazole In Situ Forming Eudragit RS Gel Comprising Different Solvents ». Key Engineering Materials 659 (août 2015) : 13–18. http://dx.doi.org/10.4028/www.scientific.net/kem.659.13.

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In situforming gel with solvent exchange mechanism is one of drug delivery systems for periodontitis treatment. The system is injected into the desired site then transforms into a gel state when the solvent diffuses out and aqueous diffuses in. Thein situforming Eudragit RSgels loading 1, 5 and 10%w/w metronidazole (MT) were developed in this study usingN-methyl pyrrolidone (NMP), 2-pyrrolidone and dimethyl sulfoxide (DMSO) as solvent. The viscosity of the gel systems in all solvents were increased as drug or polymer amount was increased with Newtonian flow behavior. Transformation into gel was evident after initiated the systems in phosphate buffer pH 6.8. NMP systems exhibited the lowest work of syringeability through 18 G syringe. Drug release from dialysis tube of DMSO systems was slower than that of NMP and 2-pyrrolidone systems, respectively. Antimicrobial activity againstStaphylococcus aureusof the systems comprising MT using NMP as solvent was greater than that using 2-pyrrolidone and DMSO, respectively, which the antimicrobial activity was increased as the drug amount was increased. Therefore, the solvent type affected the viscosity, gel formation, syringeability, drug release and antimicrobial activity of Eudragit RS systems. These developed systems sustained the drug release and inhibited the bacterial growth hence they were interesting systems for periodontitis treatment.

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Viney, C., et A. H. Windle. « Ternary Phase Equilibria for a Nitrocellulose/Solvent/Non-Solvent System ». Liquid Crystals 1, n^o 4 (juillet 1986) : 379–96. http://dx.doi.org/10.1080/02678298608086670.

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Dayal, Pratyush, et Thein Kyu. « Porous fiber formation in polymer-solvent system undergoing solvent evaporation ». Journal of Applied Physics 100, n^o 4 (15 août 2006) : 043512. http://dx.doi.org/10.1063/1.2259812.

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Murakami, Yoichi, Sudhir Kumar Das, Yuki Himuro et Satoshi Maeda. « Triplet-sensitized photon upconversion in deep eutectic solvents ». Physical Chemistry Chemical Physics 19, n^o 45 (2017) : 30603–15. http://dx.doi.org/10.1039/c7cp06494b.

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Sharma, Apekshya, Evan Yu, Gregory Morose, David Trung Nguyen et Wan-Ting Chen. « Designing Safer Solvents to Replace Methylene Chloride for Liquid Chromatography Applications Using Thin-Layer Chromatography as a Screening Tool ». Separations 8, n^o 10 (6 octobre 2021) : 172. http://dx.doi.org/10.3390/separations8100172.

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Methylene chloride, commonly known as dichloromethane (DCM), is a widely used chemical for chromatography separation within the polymer, chemical, and pharmaceutical industries. With the ability to effectively solvate heterocyclic compounds, and properties including a low boiling point, high density, and low cost, DCM has become the solvent of choice for many different applications. However, DCM has high neurotoxicity and is carcinogenic, with exposure linked to damage to the brain and the central nervous system, even at low exposure levels. This research focuses on sustainability and works towards finding safer alternative solvents to replace DCM in pharmaceutical manufacturing. The research was conducted with three active pharmaceutical ingredients (API) widely used in the pharmaceutical industry: acetaminophen, aspirin, and ibuprofen. Thin-layer chromatography (TLC) was used to investigate if an alternative solvent or solvent blend could show comparable separation performance to DCM. The use of the Hansen Solubility Parameter (HSP) theory and solubility testing allowed for the identification of potential alternative solvents or solvent blends to replace DCM. HSP values for the three APIs were experimentally determined and used to identify safer solvents and blends that could potentially replace DCM. Safer solvents or binary solvent blends were down-selected based on their dissolution power, safety, and price. The down-selected solvents (e.g., ethyl acetate) and solvent blends were further evaluated using three chemical hazard classification approaches to find the best fitting nonhazardous replacement to DCM. Several safer solvent blends (e.g., mixtures composed of methyl acetate and ethyl acetate) with adequate TLC performance were identified. Results from this study are expected to provide guidance for identifying and evaluating safer solvents to separate APIs using chromatography.

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Liu, Li Wei, Wei Min Kang, Bo Wen Cheng et Ya Liu. « PLA Nanofibers Electrospun from System of Low Toxicity Solvent ». Advanced Materials Research 221 (mars 2011) : 657–61. http://dx.doi.org/10.4028/www.scientific.net/amr.221.657.

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In this paper polylactide (PLA) nanofibers were successfully prepared via electrospinning using low toxic 1,4-dioxane and acetone as co-solvents. The morphology of nanofibers was studied by scanning electron microscopy (SEM) at the different weight ratios of co-solvent, concentrations of spinning solution, electrostatic voltages and collecting distance. Results indicate that the finer and uniform nanofibers were electrospun from the concentration of the spinning solutions at 8 wt.%, 1,4-dioxane and acetone with ratio of 40/60 (w/w), the spinning voltage at 20kV, the collecting distance at 180 mm and the extruding speed at 5 mL/h.

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Xiao, Xiu Feng, Jian Jin Jiao, Qiong Yu Huang et Rong Fang Liu. « Fabrication of Polycaprolactone/Chitosan Scaffolds by Freeze-Solvent Extraction Method ». Advanced Materials Research 311-313 (août 2011) : 1695–98. http://dx.doi.org/10.4028/www.scientific.net/amr.311-313.1695.

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The polycaprolactone (PCL)/chitosan (CS) scaffolds were prepared by the freeze-solvent extraction method using glacial acetic acid with little water as a common blend system. The effect of different solvents on the crystallinity, the morphology, the structure and the mechanical properties of the scaffolds was studied. The results indicate that alkaline solvent favors the deposition of CS, solvent extraction in the frozen condition perfects the crystal of PCL and improves the crystallinity of PCL/CS scaffolds, in the mean while, the compression property enhances. The porosity of PCL/CS reaches 81%, when immersed in water solvent.

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Jeslin, D., et K. Masilamani. « Current Insights of Nano Suspension Drug Delivery System : A Patent Review ». INTERNATIONAL JOURNAL OF DRUG DELIVERY TECHNOLOGY 14, n^o 01 (25 mars 2024) : 506–14. http://dx.doi.org/10.25258/ijddt.14.1.70.

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Unfortunately, water-solvency continues to be a usual characteristic of medication newcomers in medicine improvement pipelines today. Different cycles have been established to improve the solvency, disintegrating rate, and bioavailability associated with these dynamic fixes having a place utilizing the biopharmaceutics classification system (BCS) II through IV orders. Since the mid-2000s, nanosuspension, nanocrystal delivery, and nebulous strong scatterings have been more established approaches to overcome the obstructions of ineffective water solvent pharmaceuticals in food and drug administration (FDA) accessible goods. This work supplies a refreshed examination of nanosuspension and dissimilar strong scattering methods, particularly for orally conveyed medications. Moreover, solvency is a vital variable for medication adequacy, autonomously of the course of development. Ineffectively solvent drugs are many times difficult assignments for developers within the sector. Customary methods to improve solvency are of little significance, specifically when the pharmaceuticals are ineffectively liquid all the while they’re watery as well as non-fluid mediums. Nanosuspension technology can be employed to enhance the potency and solubility with insoluble substances medicines. Nanosuspension possesses dual-phase structures made up of precise medication particles scattered throughout a liquid medium kept in check with surfactants. Those strategies generally straightforward plan offer advantages compared to alternative methods. Various methods, comprising wet manufacturing, regions assembling, emulsifying, evaporating the solvent, and releasing simple liquid methods, are employed when making nanosuspension. Subsequently enjoys convenience conveyance via diverse courses, comprising oral, parenteral, aspiratory even visual courses. The current proposal plan provide the ongoing strategies employed to get ready small suspensions, including their application in medication conveyance

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Kaur, Gagandeep, Maryam Agboluaje et Robin A. Hutchinson. « Measurement and Modeling of Semi-Batch Solution Radical Copolymerization of N-tert-Butyl Acrylamide with Methyl Acrylate in Ethanol/Water ». Polymers 15, n^o 1 (31 décembre 2022) : 215. http://dx.doi.org/10.3390/polym15010215.

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The synthetic polymer industry is transitioning from the use of organic solvents to aqueous media in order to reduce environmental impact. However, with radical polymerization kinetics affected by hydrogen-bonding solvents, there is limited information regarding the use of water as a solvent for sparingly soluble monomers. Thus, in this paper, the radical polymerization of methyl acrylate (MA) and N-tert-butylacrylamide (t-BuAAm) is studied in water and ethanol (EtOH), as the copolymer product is of commercial interest. A series of semi-batch reactions are conducted under a range of operating conditions (i.e., reaction temperature, solvent-to-monomer ratio, and comonomer composition) to demonstrate that the copolymer can be successfully synthesized without significant drifts in product molar masses or composition. The experiments provide additional data to probe the influence of the solvent on the polymerization rate and copolymer properties, as the low monomer concentration maintained under starved-feed operation leads to a solvent-to-monomer ratio different from that in a batch system. A model that captures the influence of backbiting and solvent effects on rate, previously developed and tested against batch polymerizations, also provides an excellent description of semi-batch operation, validating the set of mechanisms and kinetic coefficients developed to represent the system.

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Karpova, M. O., N. V. Makarova, D. F. Ignatova et D. V. Budylin. « Determination of the type of solvent in the technology of production of tea extracts with antioxidant activity ». Proceedings of the Voronezh State University of Engineering Technologies 82, n^o 4 (20 janvier 2021) : 169–78. http://dx.doi.org/10.20914/2310-1202-2020-4-169-178.

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Résumé :

The aim of the study was to determine the type of solvent that allows the most complete extraction of antioxidant substances from white, black and green tea (Camellia sinensis). The objects of the study were extracts of three types of tea obtained using various solvents: water, a mixture of water-ethanol (75% vol./25% vol.), A mixture of water-ethanol (50% vol./50% vol.), A mixture of water -ethanol (25% vol./75% vol.) and ethanol (96%). In extracts of white, black and green tea, the total content of phenolic substances, flavonoids, antiradical activity by the DPPH method, and the restoring force by the FRAP method were determined. The maximum values of the total content of phenolic substances were found in the extract of white tea based on ethanol and a water-ethanol solvent system (50/50), black tea when extracted with water, green tea with a water-ethanol solvent ratio (50/50). High values of the total content of flavonoids were established for white tea extract based on a water-ethanol solvent system (50/50), black tea when extracted with water, green tea, when using ethanol as a solvent. Low antiradical activity was found in white tea extract based on a water-ethanol solvent system (50/50), in ethanol-based black tea, and green tea showed low values when extracted with water. The highest index of restorative power was found in white tea extract based on a water-ethanol solvent system (25/75), in black and green tea when extracted with water. Thus, as a result of the study of extracts of white, black and green tea, it was found that when the white tea is extracted with a water-ethanol (50/50) solvent system, the largest amount of antioxidant substances is extracted. The maximum amount of antioxidants from black and green tea is extracted using water as a solvent.

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