Artículos de revistas sobre el tema "Industrially important solvents"
Siga este enlace para ver otros tipos de publicaciones sobre el tema: Industrially important solvents.
Crea una cita precisa en los estilos APA, MLA, Chicago, Harvard y otros
Consulte los 50 mejores artículos de revistas para su investigación sobre el tema "Industrially important solvents".
Junto a cada fuente en la lista de referencias hay un botón "Agregar a la bibliografía". Pulsa este botón, y generaremos automáticamente la referencia bibliográfica para la obra elegida en el estilo de cita que necesites: APA, MLA, Harvard, Vancouver, Chicago, etc.
También puede descargar el texto completo de la publicación académica en formato pdf y leer en línea su resumen siempre que esté disponible en los metadatos.
Explore artículos de revistas sobre una amplia variedad de disciplinas y organice su bibliografía correctamente.
1
McDermott, Catherine y James J. A. Heffron. "Toxicity of Industrially Relevant Chlorinated Organic Solvents In Vitro". International Journal of Toxicology 32, n.º 2 (marzo de 2013): 136–45. http://dx.doi.org/10.1177/1091581813482006.
Texto completoResumen
The cytotoxic effects of 4 industrially important chlorinated organic solvents, dichloromethane (DCM), 1,2-dichloroethane (DCE), trichloroethylene (TCE), and tetrachloroethylene (PERC) in vitro, were investigated. Jurkat T cells were exposed to the solvents individually for 72 hours and changes in reactive oxygen species (ROS) formation, cell proliferation, intracellular free calcium concentration ([Ca2+]), and caspase-3 activity were measured. There was a concentration-dependent increase in the ROS formation and intracellular free [Ca2+] following exposure to each of the solvents. This was accompanied by a decrease in the cell proliferation. Solvent potency decreased in the following order: PERC > TCE > DCM > DCE. Caspase-3 activity was increased in a concentration-dependent manner by TCE and PERC but was not significantly altered by DCM or DCE. n-Acetyl-l-cysteine pretreatment showed that changes in the intracellular free [Ca2+] and caspase-3 activity were independent of ROS formation. However, increased ROS formation did play a causal role in the decreased cell proliferation observed.
2
An, Suna, Dahye Kwon, JeongHyun Cho y Ji Chul Jung. "Effect of the Solvent on the Basic Properties of Mg–Al Hydrotalcite Catalysts for Glucose Isomerization". Catalysts 10, n.º 11 (25 de octubre de 2020): 1236. http://dx.doi.org/10.3390/catal10111236.
Texto completoResumen
We suggested the existence of a relationship between the base properties of Mg–Al hydrotalcite catalysts and the solvents employed in the industrially important isomerization of glucose produce fructose. We prepared Mg–Al hydrotalcite catalysts with different Mg/Al atomic ratios to tune the basic properties of the catalyst. The prepared catalysts were used in the glucose isomerization conducted in various solvents. Experimental results confirmed that the catalysts exhibited different activities in the different solvents. We also implemented the Hammett indicator method, which allows to analyze the basic properties of the catalysts in various solvents. According to evidence, the basic properties of the catalysts varied substantially in different solvents. Notably, increases in the catalysts’ base properties matched the observed increases in fructose yield of the glucose isomerization. Consequently, we suggested that, in order to prepare efficient Mg–Al hydrotalcite catalysts for glucose isomerization, the interaction between the solvent used to conduct the reaction and the basic properties of the catalyst, which are in turn influenced by the solvent, should be considered.
3
Hall, T. F., R. C. Waterfall, G. J. Kakabadse, E. O. Olatoye, R. Perry y A. E. Tipping. "Computer-Controlled On-Line Moisture Measurement in Organic Solvents Using a Novel Potentiometric Technique". Measurement and Control 22, n.º 8 (octubre de 1989): 240–44. http://dx.doi.org/10.1177/002029408902200803.
Texto completoResumen
A microcomputer-based monitoring system for the determination of residual water in organic solvents using ion-selective electrodes in a novel potentiometric method, called the proton iso-concentration technique (PICT), has been developed at UMIST. In the monitor, a sample stream is bled off and mixed with a buffer solution before passing through a cell containing a pH glass electrode, a reference electrode and an automatic temperature compensation probe. The instrument is calibrated with standard solutions containing water in the same solvent. The automatic monitoring system comprises a microcomputer and slave microprocessor system, the former performing system control and data analysis, the latter controlling a number of discrete electronic devices. Results obtained on selected industrially important solvents demonstrate a satisfactory performance of PICT in continuous monitoring, showing it to be accurate, reproducible and sensitive. On-line determination of moisture in solvents is important for process control in industry.
4
Venkatramana, L., K. Sivakumar, V. Govinda y K. Dayananda Reddy. "Study on solution properties of some industrially important solvents with an aromatic alcohol". Journal of Molecular Liquids 186 (octubre de 2013): 163–70. http://dx.doi.org/10.1016/j.molliq.2013.04.026.
Texto completo
5
Peng, Shu Ge, Yong Ke Guo, Xiao Fei Liu y Jun Zhang. "The Effects of Organic Solvents on Catalytic Behavior of Immobilized Hemoglobin Nanocomposites: Functional Groups and Molecular Constitution". Advanced Materials Research 233-235 (mayo de 2011): 1556–59. http://dx.doi.org/10.4028/www.scientific.net/amr.233-235.1556.
Texto completoResumen
The use of organic solvents as reaction media for enzymatic reactions provides numerous industrially attractive advantages compared to traditional aqueous reaction systems. Hemoglobin (Hb) intercalated magadiite nano-composites was successfully prepared by exfoliation-reassembly method at room temperature and pH=7, and was used to catalyze the oxidation of o-phenylenediamine in organic solvents. Catalytic activity of immobilized Hb in organic solvents with different hydrophobicity and different functional groups were investigated detailedly. The results showed that functional groups and molecular constitution of the organic solvents were both important factors to determine catalytic activity of immobilized Hb in organic media except hydrophobicity of organic solvents.
6
Orha, László, József M. Tukacs, László Kollár y László T. Mika. "Palladium-catalyzed Sonogashira coupling reactions in γ-valerolactone-based ionic liquids". Beilstein Journal of Organic Chemistry 15 (3 de diciembre de 2019): 2907–13. http://dx.doi.org/10.3762/bjoc.15.284.
Texto completoResumen
It was demonstrated that the γ-valerolactone-based ionic liquid, tetrabutylphosphonium 4-ethoxyvalerate as a partially bio-based solvent can be utilized as alternative reaction medium for copper- and auxiliary base-free Pd-catalyzed Sonogashira coupling reactions of aryl iodides and functionalized acetylenes under mild conditions. Twenty-two cross-coupling products were isolated with good to excellent yields (72–99%) and purity (>98%). These results represent an example which proves that biomass-derived safer solvents can be utilized efficiently in common, industrially important transformations exhibiting higher chemical and environmental efficiency.
7
Sokoli, Hülya U., Morten E. Simonsen y Erik G. Søgaard. "Investigation of degradation products produced by recycling the solvent during chemical degradation of fiber-reinforced composites". Journal of Reinforced Plastics and Composites 36, n.º 17 (27 de abril de 2017): 1286–96. http://dx.doi.org/10.1177/0731684417707060.
Texto completoResumen
Recycling of fiber-reinforced thermoset composites using chemical solvolysis has been investigated thoroughly in recent years, where solvents such as water, alcohols and ketones have been used. However, high costs are related to the use of organic solvents, decreasing the sustainability of the process. In this study, acetone has been used as the organic solvent. To increase the sustainability of the process, the solvent was recycled in eight consecutive batches using new glass fiber-reinforced composites in each recycling. No additional amount of acetone was added, resulting in a reduction of solvent consumption by 88%. It was found that the recycled solvent became increasingly more concentrated with degradation products from the epoxy resin and compounds produced by acetone aldol reactions. These degradation products promoted and enhanced the degradation of the composite. Among the compounds produced by acetone aldol reaction, the industrially important bulk chemical mesityl oxide accounted for 68–79% of the total chromatographic peak area. Simultaneously, with the optimization of a process for converting composite waste into its constituent (fibers and resin), valuable bulk chemicals can be produced to increase the overall commercial interest.
8
Weidlich, Tomáš y Barbora Kamenická. "Utilization of CO2-Available Organocatalysts for Reactions with Industrially Important Epoxides". Catalysts 12, n.º 3 (6 de marzo de 2022): 298. http://dx.doi.org/10.3390/catal12030298.
Texto completoResumen
Recent knowledge in chemistry has enabled the material utilization of greenhouse gas (CO2) for the production of organic carbonates using mild reaction conditions. Organic carbonates, especially cyclic carbonates, are applicable as green solvents, electrolytes in batteries, feedstock for fine chemicals and monomers for polycarbonate production. This review summarizes new developments in the ring opening of epoxides with subsequent CO2-based formation of cyclic carbonates. The review highlights recent and major developments for sustainable CO2 conversion from 2000 to the end of 2021 abstracted by Web of Science. The syntheses of epoxides, especially from bio-based raw materials, will be summarized, such as the types of raw material (vegetable oils or their esters) and the reaction conditions. The aim of this review is also to summarize and to compare the types of homogeneous non-metallic catalysts. The three reaction mechanisms for cyclic carbonate formation are presented, namely activation of the epoxide ring, CO2 activation and dual activation. Usually most effective catalysts described in the literature consist of powerful sources of nucleophile such as onium salt, of hydrogen bond donors and of tertiary amines used to combine epoxide activation for facile epoxide ring opening and CO2 activation for the subsequent smooth addition reaction and ring closure. The most active catalytic systems are capable of activating even internal epoxides such as epoxidized unsaturated fatty acid derivatives for the cycloaddition of CO2 under relatively mild conditions. In case of terminal epoxides such as epichlorohydrin, the effective utilization of diluted sources of CO2 such as flue gas is possible using the most active organocatalysts even at ambient pressure.
9
Kótai, László, Vladimir M. Petruševski, Laura Bereczki y Kende Attila Béres. "Catalytic Properties of the Spinel-Like CuxMn3−xO4 Copper Manganese Oxides—An Overview". Catalysts 13, n.º 1 (6 de enero de 2023): 129. http://dx.doi.org/10.3390/catal13010129.
Texto completoResumen
Copper manganese oxide spinels and related (multiphase) materials with the formula CuxMn3−xO4 are the active catalysts in a wide variety of industrially important processes due to their great diversity in their phase relations, metal ion valence/site distribution, and chemical properties. In this review, we summarize the preparation methods and their effects on the composition, properties, and catalytic properties of various CuxMn3−xO4 catalysts with various Cu/Mn ratios. The main summarized catalytic reactions are the oxidation of carbon monoxide, nitrogen oxide, and hydrogen sulfide and the oxidative removal of organic solvents such as benzene, toluene, and xylene from the air. Some industrially important reactions (steam reforming of methanol or synthesis gas) and the manufacture of organic chemicals (methyl formate, propylene oxide, and benzyl alcohol) catalyzed by CuxMn3−xO4 spinels are also reviewed.
10
Roy, Mahendra Nath, Rajani Dewan, Deepak Ekka y Ishani Banik. "Probing molecular interactions of ionic liquid in industrially important solvents by means of conductometric and spectroscopic approach". Thermochimica Acta 559 (mayo de 2013): 46–51. http://dx.doi.org/10.1016/j.tca.2013.02.022.
Texto completo
11
McDermott, Catherine, Ashley Allshire, Frank van Pelt y James J. A. Heffron. "In Vitro Exposure of Jurkat T-Cells to Industrially Important Organic Solvents in Binary Combination: Interaction Analysis". Toxicological Sciences 101, n.º 2 (2 de noviembre de 2007): 263–74. http://dx.doi.org/10.1093/toxsci/kfm274.
Texto completo
12
Marullo, Salvatore y Francesca D’Anna. "The Role Played by Ionic Liquids in Carbohydrates Conversion into 5-Hydroxymethylfurfural: A Recent Overview". Molecules 27, n.º 7 (29 de marzo de 2022): 2210. http://dx.doi.org/10.3390/molecules27072210.
Texto completoResumen
Obtaining industrially relevant products from abundant, cheap, renewable, and low-impacting sources such as lignocellulosic biomass, is a key step in reducing consumption of raw fossil materials and, consequently, the environmental footprint of such processes. In this regard, a molecule that is similar to 5-hydroxymethylfurfural (5-HMF) plays a pivotal role, since it can be produced from lignocellulosic biomass and gives synthetic access to a broad range of industrially important products and polymers. Recently, ionic liquids (ILs) have emerged as suitable solvents for the conversion of biomass and carbohydrates into 5-HMF. Herein, we provide a bird’s-eye view on recent achievements about the use of ILs for the obtainment of 5-HMF, covering works that were published over the last five years. In particular, we first examine reactions involving homogeneous catalysis as well as task-specific ionic liquids. Then, an overview of the literature addressing the use of heterogeneous catalysts, including enzymes, is presented. Whenever possible, the role of ILs and catalysts driving the formation of 5-HMF is discussed, also comparing with the same reactions that are performed in conventional solvents.
13
Kumar, Satish, Wonsub Lim, Younghee Lee, Jaibir S. Yadav, Dimple Sharma, V. K. Sharma y Il Moon. "Thermodynamic and acoustic properties for binary and ternary mixtures of cyclic ethers with industrially important solvents at 308.15K". Journal of Molecular Liquids 155, n.º 1 (agosto de 2010): 8–15. http://dx.doi.org/10.1016/j.molliq.2010.04.007.
Texto completo
14
Willför, Stefan, Linda Nisula, Jarl Hemming, Markku Reunanen y Bjarne Holmbom. "Bioactive phenolic substances in industrially important tree species. Part 2: Knots and stemwood of fir species". Holzforschung 58, n.º 6 (1 de octubre de 2004): 650–59. http://dx.doi.org/10.1515/hf.2004.119.
Texto completoResumen
Abstract Knots, i.e. branch bases inside tree stems, in fir trees contained remarkably higher concentrations of lignans, oligolignans, and juvabiones than the adjacent stemwood. Eight fir species were analysed (Abies sibirica, A. lasiocarpa, A. balsamea, A. alba, A. amabilis, A. veitchii, A. sachalinensis, and A. concolor). The amount of lignans could in some knots exceeds 6% (w/w) and the knots generally contained 20–50 times more lignans than the stemwood. However, there were large variations, not only between species but also even between knots in the same tree. Secoisolariciresinol was the predominant lignan in all knots. The lignans occur in free form in the knots and are easily extracted with polar solvents. In addition to the lignans, oligomeric aromatic substances, mainly sesquineo- and dineolignans, and juvabiones were accumulated in the knotwood. Secoisolariciresinol, but also lariciresinol (Abies alba) and 7-hydroxymatairesinol (A. amabilis), could be extracted in large scale from fir knots at pulp and paper mills. The ready availability of large amounts of lignans and oligolignans now enables research to assess their bioactivity and provide the base for applications in medicine and nutrition, or as natural antioxidants and antimicrobial agents in various technical products.
15
Roy, Mahendra Nath, Rajesh Kumar Das y Riju Chanda. "Study on Solution Properties of Binary Mixtures of Some Industrially Important Solvents with Cyclohexylamine and Cyclohexanone at 298.15 K". International Journal of Thermophysics 31, n.º 3 (marzo de 2010): 535–45. http://dx.doi.org/10.1007/s10765-010-0752-6.
Texto completo
16
Ramalhete, Susana M., Jamie S. Foster, Hayley R. Green, Karol P. Nartowski, Margaux Heinrich, Peter C. Martin, Yaroslav Z. Khimyak y Gareth O. Lloyd. "Halogen effects on the solid-state packing of phenylalanine derivatives and the resultant gelation properties". Faraday Discussions 203 (2017): 423–39. http://dx.doi.org/10.1039/c7fd00108h.
Texto completoResumen
Phenylalanine is an important amino acid both biologically, essential to human health, and industrially, as a building block of artificial sweeteners. Our interest in this particular amino acid and its derivatives lies with its ability to form gels in a number of solvents. We present here the studies of the influence of halogen addition to the aromatic ring on the gelation properties and we analyse the crystal structures of a number of these materials to elucidate the trends in their behaviour based on the halogen addition to the aromatic group and the interactions that result.
17
Willför, S., L. Nisula, J. Hemming, M. Reunanen y B. Holmbom. "Bioactive phenolic substances in industrially important tree species. Part 1: Knots and stemwood of different spruce species". Holzforschung 58, n.º 4 (7 de julio de 2004): 335–44. http://dx.doi.org/10.1515/hf.2004.052.
Texto completoResumen
Abstract Knots (i.e., branch bases inside tree stems) in spruce trees contained remarkably higher concentrations of lignans and oligolignans than the adjacent stemwood. The amount of lignans in some knots exceeded 10% (w w−1) and some knots contained hundreds of times more lignans than the heartwood in the same tree. However, there were large variations between different species and even between different knots in the same tree. 7-Hydroxymatairesinol was the predominant lignan in knots of Picea abies, P. glauca, P. koraiensis, P. mariana, and P. omorika, while liovil and secoisolariciresinol dominated in P. sitchensis and P. pungens. The lignans occur in free form in knots and are easily extracted with polar solvents. In addition to the true lignans, especially the knots contained large amounts of lignan-related oligomeric aromatic substances, here called oligolignans, consisting of three or four phenylpropane units. 7-Hydroxymatairesinol, but also other lignans, could be extracted in large scale from spruce knots at pulp and paper mills. Other potentially important lignans could be produced from 7-hydroxymatairesinol by semisynthesis. The ready availability of large amounts of lignans and oligolignans now enables research to assess their bioactivity and provide the basis for applications in medicine and nutrition or as natural antioxidants and antimicrobial agents in a variety of technical products.
18
Maniam, Kranthi Kumar y Shiladitya Paul. "Ionic Liquids and Deep Eutectic Solvents for CO2 Conversion Technologies—A Review". Materials 14, n.º 16 (11 de agosto de 2021): 4519. http://dx.doi.org/10.3390/ma14164519.
Texto completoResumen
Ionic liquids (ILs) have a wide range of potential uses in renewable energy, including CO2 capture and electrochemical conversion. With the goal of providing a critical overview of the progression, new challenges, and prospects of ILs for evolving green renewable energy processes, this review emphasizes the significance of ILs as electrolytes and reaction media in two primary areas of interest: CO2 electroreduction and organic molecule electrosynthesis via CO2 transformation. Herein, we briefly summarize the most recent advances in the field, as well as approaches based on the electrochemical conversion of CO2 to industrially important compounds employing ILs as an electrolyte and/or reaction media. In addition, the review also discusses the advances made possible by deep eutectic solvents (DESs) in CO2 electroreduction to CO. Finally, the critical techno-commercial issues connected with employing ILs and DESs as an electrolyte or ILs as reaction media are reviewed, along with a future perspective on the path to rapid industrialization.
19
Khokarale, Santosh, Ganesh Shelke y Jyri-Pekka Mikkola. "Integrated and Metal Free Synthesis of Dimethyl Carbonate and Glycidol from Glycerol Derived 1,3-Dichloro-2-propanol via CO2 Capture". Clean Technologies 3, n.º 4 (24 de septiembre de 2021): 685–98. http://dx.doi.org/10.3390/cleantechnol3040041.
Texto completoResumen
Dimethyl carbonate (DMC) and glycidol are considered industrially important chemical entities and there is a great benefit if these moieties can be synthesized from biomass-derived feedstocks such as glycerol or its derivatives. In this report, both DMC and glycidol were synthesized in an integrated process from glycerol derived 1,3-dichloro-2-propanol and CO2 through a metal-free reaction approach and at mild reaction conditions. Initially, the chlorinated cyclic carbonate, i.e., 3-chloro-1,2-propylenecarbonate was synthesized using the equivalent interaction of organic superbase 1,8-diazabicyclo [5.4.0] undec-7-ene (DBU) and 1,3-dichloro-2-propanol with CO2 at room temperature. Further, DMC and glycidol were synthesized by the base-catalyzed transesterification of 3-chloro-1,2-propylenecarbonate using DBU in methanol. The synthesis of 3-chloro-1,2-propylenecarbonate was performed in different solvents such as dimethyl sulfoxide (DMSO) and 2-methyltetrahydrofuran (2-Me-THF). In this case, 2-Me-THF further facilitated an easy separation of the product where a 97% recovery of the 3-chloro-1,2-propylenecarbonate was obtained compared to 63% with DMSO. The use of DBU as the base in the transformation of 3-chloro-1,2-propylenecarbonate further facilitates the conversion of the 3-chloro-1,2 propandiol that forms in situ during the transesterification process. Hence, in this synthetic approach, DBU not only eased the CO2 capture and served as a base catalyst in the transesterification process, but it also performed as a reservoir for chloride ions, which further facilitates the synthesis of 3-chloro-1,2-propylenecarbonate and glycidol in the overall process. The separation of the reaction components proceeded through the solvent extraction technique where a 93 and 89% recovery of the DMC and glycidol, respectively, were obtained. The DBU superbase was recovered from its chlorinated salt, [DBUH][Cl], via a neutralization technique. The progress of the reactions as well as the purity of the recovered chemical species was confirmed by means of the NMR analysis technique. Hence, a single base, as well as a renewable solvent comprising an integrated process approach was carried out under mild reaction conditions where CO2 sequestration along with industrially important chemicals such as dimethyl carbonate and glycidol were synthesized.
20
Mahato, Neelima, Kavita Sharma, Mukty Sinha, Archana Dhyani, Brajesh Pathak, Hyeji Jang, Seorin Park, Srinath Pashikanti y Sunghun Cho. "Biotransformation of Citrus Waste-I: Production of Biofuel and Valuable Compounds by Fermentation". Processes 9, n.º 2 (25 de enero de 2021): 220. http://dx.doi.org/10.3390/pr9020220.
Texto completoResumen
Citrus is the largest grown fruit crop on the globe with an annual production of ~110–124 million tons. Approximately, 45–55% of the whole fruit post-processing is generally discarded as waste by the food processing industries. The waste is a huge problem to the environment in terms of land and water pollution along with displeasure from aesthetic viewpoint and spread of diseases owing to its huge content of fermentable sugars. The waste can be utilized as a raw material feedstock for producing a number of valuable chemicals and products, such as bioethanol, biogas, bio-oil, organic acids, enzymes, and so on. The production of these chemicals from waste biomass gives an inexpensive alternative to the harsh chemicals used during industrial synthesis processes as well as the possibility of controlling pollution from the waste discarded to the environment. The derived chemicals can be further utilized in the production of industrially important chemicals, as solvents and building blocks of newer chemicals. Furthermore, organic acids, pectin, enzymes, prebiotics, etc., derived from citrus wastes have an edge over their synthetic counterparts in practical applications in the food processing and pharmaceutical industries.
21
Kumar, Komal, Mukesh Kumar y Sreedevi Upadhyayula. "Catalytic Conversion of Glucose into Levulinic Acid Using 2-Phenyl-2-Imidazoline Based Ionic Liquid Catalyst". Molecules 26, n.º 2 (12 de enero de 2021): 348. http://dx.doi.org/10.3390/molecules26020348.
Texto completoResumen
Levulinic acid (LA) is an industrially important product that can be catalytically valorized into important value-added chemicals. In this study, hydrothermal conversion of glucose into levulinic acid was attempted using Brønsted acidic ionic liquid catalyst synthesized using 2-phenyl-2-imidazoline, and 2-phenyl-2-imidazoline-based ionic liquid catalyst used in this study was synthesized in the laboratory using different anions (NO3, H2PO4, and Cl) and characterized using 1H NMR, TGA, and FT-IR spectroscopic techniques. The activity trend of the Brønsted acidic ionic liquid catalysts synthesized in the laboratory was found in the following order: [C4SO3HPhim][Cl] > [C4SO3HPhim][NO3] > [C4SO3HPhim][H2PO4]. A maximum 63% yield of the levulinic acid was obtained with 98% glucose conversion at 180 °C and 3 h reaction time using [C4SO3HPhim][Cl] ionic liquid catalyst. The effect of different reaction conditions such as reaction time, temperature, ionic liquid catalyst structures, catalyst amount, and solvents on the LA yield were investigated. Reusability of [C4SO3HPhim][Cl] catalyst up to four cycles was observed. This study demonstrates the potential of the 2-phenyl-2-imidazoline-based ionic liquid for the conversion of glucose into the important platform chemical levulinic acid.
22
Winterton, Neil. "The green solvent: a critical perspective". Clean Technologies and Environmental Policy 23, n.º 9 (30 de septiembre de 2021): 2499–522. http://dx.doi.org/10.1007/s10098-021-02188-8.
Texto completoResumen
AbstractSolvents are important in most industrial and domestic applications. The impact of solvent losses and emissions drives efforts to minimise them or to avoid them completely. Since the 1990s, this has become a major focus of green chemistry, giving rise to the idea of the ‘green’ solvent. This concept has generated a substantial chemical literature and has led to the development of so-called neoteric solvents. A critical overview of published material establishes that few new materials have yet found widespread use as solvents. The search for less-impacting solvents is inefficient if carried out without due regard, even at the research stage, to the particular circumstances under which solvents are to be used on the industrial scale. Wider sustainability questions, particularly the use of non-fossil sources of organic carbon in solvent manufacture, are more important than intrinsic ‘greenness’. While solvency is universal, a universal solvent, an alkahest, is an unattainable ideal.
23
Thomas, Shibin, Victoria K. Greenacre, Yasir J. Noori, Nema M. Abdelazim, Jiapei Zhang, Sarah A. Alodan, Sami Ramadan et al. "Electrodeposition of Transition Metal Dichalcogenide Thin- Films from Non-Aqueous Solvents". ECS Meeting Abstracts MA2023-02, n.º 20 (22 de diciembre de 2023): 1218. http://dx.doi.org/10.1149/ma2023-02201218mtgabs.
Texto completoResumen
Transition metal dichalcogenides (TMDCs) are an interesting group of 2D materials characterised with a layered structure analogous to graphene and they possess unique electronic and optical properties, especially when in the few- and mono-layer form. Developing scalable techniques for depositing TMDCs is a major challenge which needs to be overcome to fabricate functional devices with these materials. Electrodeposition is an industrially relevant technique that has some key advantages over other conventional deposition methods. It is a low cost and easily scalable technique and could be used for obtaining complex nanoscale features and for depositing over topologically demanding surfaces. Even though the electrodeposition of MoS2 has been achieved both in aqueous and non-aqueous electrolytes, not much progress has been made in the deposition of other TMDC materials. Tungsten based TMDCs such as WS2 and WSe2 are shown to be very promising materials in different applications, however electrodepositing them remains extremely challenging. One of the major obstacles here is developing electrochemically active precursors which are compatible with the electrolyte system and able to deliver both the tungsten and chalcogens to the electrolyte. Controlling and optimizing the deposition process to obtain few- and mono-layer TMDCs is another challenge. In addition, the choice of substrates for deposition is very important, especially for direct growth of ultra-thin TMDCs. Electrodeposition, being a bottom-up deposition method, would benefit from an atomically thin and smooth substrate such as graphene for depositing few- and mono-layer TMDCs. Here we present non-aqueous electroplating as a scalable alternative technique for tungsten-based TMDC deposition, with WS2 and WSe2 as examples. Tailored single source precursors were developed to use in non-aqueous electrolytes. WS2 was electrodeposited from dichloromethane (CH2Cl2) using the [NEt4]2[WS2Cl4] precursor. WSe2 was then electrodeposited from acetonitrile (CH3CN) electrolyte using [WSeCl4] as the precursor. Electrochemical quartz crystal microbalance (EQCM) studies were performed to optimize the deposition process and to probe the mechanism of precursor electrochemistry. Electrochemical deposition parameters were then carefully adjusted to obtain few- and mono-layer TMDCs. Patterned graphene electrodes were used as an atomically thin and smooth platform for the deposition of few- and mono-layer WS2. Few-layer TMDC films obtained on graphene were found to be much smoother than films deposited on other standard substrates such as titanium nitride (TiN) or Pt. These TMDC/graphene structures gave interesting 2D heterostructures which are technologically important for different applications. This work was funded by EPSRC grant references EP/V062689/1, EP/V062387/1 and EP/P025137/1
24
Saxena, Rajshree y Rajni Singh. "MALDI-TOF MS and CD Spectral Analysis for Identification and Structure Prediction of a Purified, Novel, Organic Solvent Stable, Fibrinolytic Metalloprotease fromBacillus cereusB80". BioMed Research International 2015 (2015): 1–13. http://dx.doi.org/10.1155/2015/527015.
Texto completoResumen
The ability to predict protein function from structure is becoming increasingly important; hence, elucidation and determination of protein structure become the major steps in proteomics. The present study was undertaken for identification of metalloprotease produced byBacillus cereusB80 and recognition of characteristics that can be industrially exploited. The enzyme was purified in three steps combining precipitation and chromatographic methods resulting in 33.5% recovery with 13.1-fold purification of enzyme which was detected as a single band with a molecular mass of 26 kDa approximately in SDS-PAGE and zymogram. The MALDI-TOF MS showed that the enzyme exhibited 70–93% similarity with zinc metalloproteases from various strainsBacillussp. specifically fromBacillus cereusgroup. The sequence alignment revealed the presence of zinc-binding region VVVHEMCHMV in the most conserved C terminus region. Secondary structure of the enzyme was obtained by CD spectra and I-TASSER. The enzyme kinetics revealed a Michaelis constant(Km)of 0.140 μmol/ml andVmaxof 2.11 μmol/min. The application studies showed that the enzyme was able to hydrolyze various proteins with highest affinity towards casein followed by BSA and gelatin. The enzyme exhibited strong fibrinolytic, collagenolytic, and gelatinolytic properties and stability in various organic solvents.
25
Duraipandian, M., H. Abirami, K. Musthafa y S. Karuthapandian. "Evaluation of Antibacterial Activity and Characterization of Phytochemical Compounds from Selected Mangrove Plants". International Journal of Biomedicine 12, n.º 4 (5 de diciembre de 2022): 640–43. http://dx.doi.org/10.21103/article12(4)_oa22.
Texto completoResumen
The aim of this study was to investigate the antibacterial activity of n-butanol, petroleum ether, ethyl acetate, ethanol, methanol, and chloroform extracts of the sponges and leaves of different mangrove species (Bruguiera cylindrica, Suaeda maritima, Ceriops decandra, Avicennia officinalis, Rhizophora apiculata, Suaeda monoica, Avicennia marina, and Rhizohora mucronata) against Proteus mirabilis ATCC 7002. Methods and Results: Agar well diffusion method was used to evaluate the antimicrobial activity of selected mangrove extracts. The active compounds from mangrove sponges and leaves with various solvents were examined under Fourier transform infrared (FTIR) spectroscopy. The ethyl acetate extracts, methanol extracts, chloroform extracts, n-butanol extracts, and petroleum ether extracts of selected mangrove leaves (B. cylindrical, S. maritime, A. officinalis, S. monoica, A. marina, R. mucronata) showed good antibacterial activity against P. mirabilis ATCC 7002. FTIR analysis of crude methanol extract of S. monoica showed the presence of amide and alkane groups in phytochemicals. For crude methanol extract of R. mucronata, the presence of phenol, nitro, amide, and alkane groups was revealed. Conclusion: the results obtained revealed industrially important mangrove extracts and the functional groups of plant compounds responsible for great antibacterial activity.
26
Hajji Nabih, Meryem, Hamza Boulika, Maryam El Hajam, Mohammed I. Alghonaim, Noureddine Idrissi Kandri, Sulaiman A. Alsalamah y Fehmi Boufahja. "Successive Solvent Extraction, Characterization and Antioxidant Activities of Cardoon Waste (Leaves and Stems) Extracts: Comparative Study". Molecules 28, n.º 3 (23 de enero de 2023): 1129. http://dx.doi.org/10.3390/molecules28031129.
Texto completoResumen
The main interest in the valorization of vegetable wastes is due to the peculiarity of their chemical composition in substances that present important properties. Among these substances, antioxidants could replace those industrially manufactured. In the present study, three solvents of different polarities (hexane, ethanol, and water) were applied for the extraction of phenolic compounds from Cynara cardunculus L. waste using two extraction methods: Soxhlet Extraction (SE) and Ultrasonic-Assisted Extraction (UAE). The obtained extracts were then characterized by Fourier-Transform Infrared (FTIR) spectroscopy and spectrophotometric determination of Total Phenolics (TPC), Total Flavonoids (TFC), and Condensed Tannins (CT). Total Antioxidant Capacity (TAC) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging activity of ethanol and water extracts of leaves and stems were also evaluated. High extraction yields were obtained by UAE. Water extracts had high yield regardless of the technique used for leaves and stems, and these extracts showed high TAC of 534.72 ± 3.83 mg AAE/g FM for leaves and 215.70 ± 8.87 mg AAE/g FM (mg of ascorbic acid equivalent per g of FM) for stems, and IC50 of 2077.491 μg/mL for leaves and 1248.185 μg/mL for stems. We explain the latter by the high total phenolic contents (TPCs), which reach 579.375 ± 3.662 mg GAE/g FM (mg of gallic acid equivalents per g of fresh matter) for leaves and 264.906 ± 3.500 mg GAE/g FM for stems. These results confirmed that the leaves and stems of the studied cardoon waste were, indeed, interesting sources of natural antioxidants.
27
Tonova, Konstantza. "Ionic liquid-assisted biphasic systems for downstream processing of fermentative enzymes and organic acids". Physical Sciences Reviews 6, n.º 3 (8 de diciembre de 2020): 1–33. http://dx.doi.org/10.1515/psr-2018-0068.
Texto completoResumen
Abstract Room-temperature ionic liquids (ILs) represent molten salts entirely consisting of ions, usually a charge-stabilized organic cation and an inorganic or organic anion. ILs are liquids at ambient temperature but possess characteristics unusual for the common liquid solvents, such as negligible vapor pressure, high thermal stability and most over the ability to mix and match libraries of cations and anions in order to acquire desirable physical and chemical properties [1]. The opportunity to obtain tunable density, viscosity, polarity and miscibility with common molecular liquids gave rise to a variety of applications of the ILs [2] as environmentally benign solvents, extractants or auxiliaries. In particular, numbers of innovations in the methods for recovery and purification of biologically derived compounds involve ILs used solo or partnered with other liquids in biphasic systems [3,4,5]. It should be noted that the ILs are not intrinsically greener than the traditional solvents, given that their production is usually more resource-demanding, but the inherent potential for recycling and reuse, and for prevention of chemical accidents gives the ILs advantages ahead. The present chapter provides a state-of-the-art overview on the basic applications of the ILs in biphasic systems aimed at downstream processing of valuable fermentative products, enzymes and organic acids. Main industrially important enzymes, lipases and carbohydrases, are considered and a description of the IL-assisted aqueous biphasic systems (ABS) and the results obtained in view of enzyme yield and purity is made. ILs serve different functions in the ABS, main phase-segregating constituents (mostly in the IL/salt ABS) or adjuvants to the polymer/salt ABS. Enzyme isolation from the contaminant proteins present in the feedstock can be carried out either in the IL-rich or in the salt-rich phase of the ABS and for the reader’s convenience the two options are described separately. Discussion on the factors and parameters affecting the enzyme partitioning in the ABS with ILs guides the reader through the ways by which the interactions between the IL and the enzyme can be manipulated in favor of the enzyme purification through the choice of the ABS composition (IL, salt, pH) and the role of the water content and the IL-rich phase structure. The second part of the chapter is dedicated to the recovery of fermentative organic acids. Mostly hydrophobic ILs have been engaged in the studies and the biphasic systems thereof are summarized. The systems are evaluated by the extraction efficiency and partition coefficient obtained. Factors and parameters affecting the extraction of organic acids by ILs are highlighted in a way to unravel the extraction mechanism. The choice of IL and pH determines the reactive mechanism and the ion exchange, while the water content and the IL phase structure play roles in physical extraction. Procedures undertaken to enhance the efficiency and to intensify the process of extraction are also looked over. Finally, the experimental holes that need fill up in the future studies are marked. According to the author’s opinion an intense research with hydrophobic ILs is suggested as these ILs have been proved milder to the biological structures (both the microbial producer and the enzyme product), more effective in the organic acid recovery and suitable to perform “in situ” extraction. Extractive fermentation entails validation of ecological and toxicological characteristics of the ILs. The protocols for re-extraction of fermentative products separated by IL-assisted biphasic systems should be clearly settled along with the methods for ILs recycling and reuse. Novel more flexible approaches to process intensification can be implemented in order to adopt the separation by biphasic systems for use in industry.
28
Marcoulaki, Effie y Pantelis Baxevanidis. "Screening for New Efficient and Sustainable-by-Design Solvents to Assist the Extractive Fermentation of Glucose to Bioethanol Fuels". Separations 9, n.º 3 (25 de febrero de 2022): 60. http://dx.doi.org/10.3390/separations9030060.
Texto completoResumen
The production of bioethanol fuels using extractive fermentation increases the efficiency of the bioconversion reaction by reducing the toxic product inhibition. The choice of appropriate solvents to remove the bioethanol product without inhibiting the fermentation is important to enable industrial scale application. This work applies computer-aided molecular design technologies to systematically screen a wide variety of candidate solvents to enhance the separation, also considering the microorganisms that perform the fermentation. The performance of the candidates was evaluated using a rigorous process simulator for extractive fermentation, assisted by functional group-contribution (QSPR/QSAR) models for the prediction of various solvent properties, including toxicity and life cycle impacts. The solvent designs generated through this approach can provide powerful insights on the kind of molecular structures and functionalities that satisfy the process objectives and constraints, as well the desired sustainability features.
29
Cavalcanti, Vytória Piscitelli, Smail Aazza, Suzan Kelly Vilela Bertolucci, João Pedro Miranda Rocha, Adriane Duarte Coelho, Altino Júnior Mendes Oliveira, Laís Campelo Mendes et al. "Solvent Mixture Optimization in the Extraction of Bioactive Compounds and Antioxidant Activities from Garlic (Allium sativum L.)". Molecules 26, n.º 19 (4 de octubre de 2021): 6026. http://dx.doi.org/10.3390/molecules26196026.
Texto completoResumen
Garlic is a health promoter that has important bioactive compounds. The bioactive extraction is an important step in the analysis of constituents present in plant preparations. The purpose of this study is to optimize the extraction with the best proportion of solvents to obtain total phenolic compounds (TPC) and thiosulfinates (TS) from dried garlic powder, and evaluate the antioxidant activities of the optimized extracts. A statistical mixture simplex axial design was used to evaluate the effect of solvents (water, ethanol, and acetone), as well as mixtures of these solvents, after two ultrasound extraction cycles of 15 min. Results showed that solvent mixtures with a high portion of water and pure water were efficient for TPC and TS recovery through this extraction procedure. According to the regression model computed, the most significant solvent mixtures to obtain high TPC and TS recovery from dried garlic powder are, respectively, the binary mixture with 75% water and 25% acetone and pure water. These optimized extracts presented oxygen radical absorbance capacity. Pure water was better for total antioxidant capacity, and the binary mixture of water–acetone (75:25) was better for DPPH scavenging activity. These optimized extracts can be used for industrial and research applications.
30
Nakamura, Yuto, Yasushi Sato, Naoki Shida y Mahito Atobe. "(Digital Presentation) Electro-Oxidative Trimerization of Catechol to Hexahydroxytriphenylene Using a Flow Microreactor". ECS Meeting Abstracts MA2022-01, n.º 42 (7 de julio de 2022): 1840. http://dx.doi.org/10.1149/ma2022-01421840mtgabs.
Texto completoResumen
Due to their unique spectroscopic and geometric features, discotic liquid crystals (DLCs) have a variety of possible applications, including optical compensation films for liquid crystal displays, organic semiconductors for electronic devices, organic light-emitting diodes (OLEDs), and organic photovoltaic cells (OPVs). The most basic molecular structure of DLC is that of a triphenylene core surrounded by alkoxy and acyloxy groups. Even today, triphenylene with 2,3,6,7,10,11-hexaalkoxy and acyloxy groups is considered to be a common structural motif of DLC, and is undergoing rapid development. Until the 1990s, many studies had been reported on the synthesis of these hexasubstituted triphenylenes by trimerization of 1,2-disubstituted benzenes, but these protocols were not practical industrially due to the limitation of substituents, lack of reproducibility, the need for strict temperature control at -80°C, and poor solubility of reagents. Hence, today, the introduction of alkyl or acyl groups into 2,3,6,7,10,11-hexahydroxytriphenylene (HHTP) has become a common synthetic strategy for hexasubstituted triphenylene. Therefore, HHTP is an important starting material for the synthesis of various types of hexasubstituted triphenylene. HHTP was conventionally synthesized by oxidative trimerization of 1,2-dimethoxybenzene followed by demethylation of the resulting hexamethoxytriphenylene. However, this method required the use of at least a stoichiometric amount of sulfuric acid, which generated a large amount of waste acid. Therefore, the development of more efficient methods, such as trimerization of 1,2-dihydroxybenzene (catechol) to HHTP, has been actively studied in recent years. Kobori et al. synthesized HHTP in 70-76% yield by oxidative trimerization of catechol using FeCl3 as an oxidant. However, the HHTP product was contaminated with Fe impurities, which was undesirable for the application of DLC in the display and semiconductor industries. Furthermore, this protocol includes a reduction step of peroxidized HHTP (quinone), which accounts for 40-60% of the total HHTP yields. Some other protocols do not use metal reagents, but they use 60-80 wt% H2SO4 aq., which result in a large amount of waste acid. On the other hand, we have recently developed an efficient method for aromatic C,C-coupling reactions by electrochemical oxidation in a flow microreactor. In this synthetic method, peroxidation of the products can be avoided by controlling the residence time in the reactor. In addition, electrochemical oxidation can be carried out without the use of oxidants or catalysts. Thus, this synthetic method has many features to overcome the drawbacks of conventional methods. In this study, we have successfully carried out the electro-oxidative trimerization of catechol in a flow microreactor to synthesize HHTP efficiently without the need for metallic reagents and reduction procedures. As a result, HHTP was obtained in 20% yield using 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) as a solvent. The results showed that the radical cations of catechol, which were generated on the anode surface, proceeds C,C-coupling in HFIP. On the other hand, the yield decreased to 4% or 0% when HFIP/H2O mixed solvents were used. DFT calculation suggested that the proton dissociation equilibrium of catechol intermediate greatly affects the reaction mechanism. We calculated the pK a values of catechol intermediate in each HFIP/H2O solvent composition, and discussed the effect of H2O contamination on the HHTP yield. Figure 1
31
Sahoo, Tejaswini, Jagannath Panda, Jnanaranjan Sahu, Dayananda Sarangi, Sunil K. Sahoo, Braja B. Nanda y Rojalin Sahu. "Green Solvent: Green Shadow on Chemical Synthesis". Current Organic Synthesis 17, n.º 6 (25 de septiembre de 2020): 426–39. http://dx.doi.org/10.2174/1570179417666200506102535.
Texto completoResumen
The natural beauty and purity of our planet has been contaminated deeply due to human selfish activities such as pollution, improper waste management, and various industrial and commercial discharges of untreated toxic by-products into the lap of nature. The collective impact of these hazardous suspensions into the natural habitat is very deadly. Challenges due to human activity on the environment have become ubiquitous. The chemical industry has a major role in human evolution and, predictably, opened gates of increased risk of pollution if the production is not done sustainably. In these circumstances, the notion of Green Chemistry has been identified as the efficient medium of synthesis of chemicals and procedures to eradicate the toxic production of harmful substances. Principles of Green Chemistry guide the scientist in their hunt towards chemical synthesis which requires the use of solvents. These solvents contaminate our air, water, land and surrounding due to its toxic properties. Even though sufficient precautions are taken for proper disposal of these solvents but it is difficult to be recycled. In order to preserve our future and coming generation from the adverse impacts associated with solvents it is very important to find alternative of this which will be easy to use, reusable and also eco-friendly. Solvents are used daily in various industrial processes as reaction medium, as diluters, and in separation procedures. As reaction medium, the role of solvent is to bring catalysts and reactants together and to release heat thus affecting activity and selectivity. The proper selection of the solvent considering its biological, physical and chemical properties is very necessary for product separation, environmental, safety handling and economic factors. Green solvents are the boon in this context. They are not only environmentally benign but also cost effective. The biggest challenge faced by the chemists is adaptation of methods and selection of solvents during chemical synthesis which will give negligible waste product and will remain human and nature friendly. During designing compounds for a particular reaction it is difficult to give assurance regarding the toxicity and biodegradability of the method. Chemists are still far away from predicting the various chemical and biological effects of the compounds on the back of the envelope. To achieve that point is formidable task but it will definitely act as inspiration for the coming generation of chemists. The green solvents are undoubtedly a far better approach to eliminate the negative impacts and aftermath of any chemical synthesis on the environment. Our study in this review covers an overview of green solvents, their role in safer chemical synthesis with reference to some of the important green solvents and their detail summarization.
32
Le, Thong Hoang, Khanh B. Vu, Quynh-Thy Song Nguyen, Phat Van Huynh, Khanh-Ly T. Huynh, Khoa Dang Tong, Thong Le Minh Pham, An Tran Nguyen Minh, Van Cuong Nguyen y Thanh Khoa Phung. "Fractionation of lignin produced from the Earleaf Acacia tree by sequential industrial organic solvents". Science and Technology Development Journal 24, n.º 1 (22 de febrero de 2021): 1835–41. http://dx.doi.org/10.32508/stdj.v24i1.2509.
Texto completoResumen
Introduction: Understanding the fractions of lignin is important for further conversion of lignin into valuable products. Herein, the “home-made” lignin from Earleaf Acacia tree was extracted by sequential industrial organic solvent and characterized each fraction to reveal its properties for further catalytic applications.
Methods: In this work, lignin was prepared from the Earleaf Acacia tree using the soda method. Then, the prepared lignin was fractionated by sequential solvents of ethyl acetate, ethanol, methanol, and acetone. Each lignin fractions were characterized by FT-IR and GPC.
Results: The FT-IR results confirmed the soda method can produce lignin from woodchips. The fractionation of lignin separated the lignin mixture into different molecular weight fraction from light – medium into heavy compounds.
Conclusion: Lignin was produced from woodchips using the soda method successfully. The fractionation using the sequential organic solvents showed the separation of different molecular weight of lignin, which allow to apply for the further conversion into useful products.
33
Bezsudnova, Ekaterina Yu, Alena Yu Nikolaeva, Sergey Y. Kleymenov, Tatiana E. Petrova, Sofia A. Zavialova, Kristina V. Tugaeva, Nikolai N. Sluchanko y Vladimir O. Popov. "Counterbalance of Stability and Activity Observed for Thermostable Transaminase from Thermobaculum terrenum in the Presence of Organic Solvents". Catalysts 10, n.º 9 (6 de septiembre de 2020): 1024. http://dx.doi.org/10.3390/catal10091024.
Texto completoResumen
Pyridoxal-5’-phosphate-dependent transaminases catalyze stereoselective amination of organic compounds and are highly important for industrial applications. Catalysis by transaminases often requires organic solvents to increase the solubility of reactants. However, natural transaminases are prone to inactivation in the presence of water-miscible organic solvents. Here, we present the solvent tolerant thermostable transaminase from Thermobaculum terrenum (TaTT) that catalyzes transamination between L-leucine and alpha-ketoglutarate with an optimum at 75 °C and increases the activity ~1.8-fold upon addition of 15% dimethyl sulfoxide or 15% methanol at high but suboptimal temperature, 50 °C. The enhancement of the activity correlates with a decrease in the thermal denaturation midpoint temperature. The blue-shift of tryptophan fluorescence suggested that solvent molecules penetrate the hydration shell of the enzyme. Analysis of hydrogen bonds in the TaTT dimer revealed a high number of salt bridges and surface hydrogen bonds formed by backbone atoms. The latter are sensitive to the presence of organic solvents; they rearrange, conferring the relaxation of some constraints inherent to a thermostable enzyme at low temperatures. Our data support the idea that the counterbalance of stability and activity is crucial for the catalysis under given conditions; the obtained results may be useful for fine-tuning biocatalyst efficiency.
34
Visak, Zoran. "Liquid-liquid equilibria in solutions with potential ecological importance". Journal of the Serbian Chemical Society 75, n.º 8 (2010): 1161–11165. http://dx.doi.org/10.2298/jsc100223100v.
Texto completoResumen
In the last three years, our research follows two main issues, defined by the slogans: ?Green Meets Toxic? and ?Green Meets Green?. The first issue considers the potential use of ambient friendly solvents for toxic organic compounds of industrial and practical importance. The other is related to liquid phase behavior in solutions of ecologically sustainable substances. The ?Green? solvents studied are: ionic liquids, liquid poly(ethylene glycol), glycerol and 1,2 and 1,3-propanediol.
35
Sas, Domínguez y González. "Recovery and Elimination of Phenolic Pollutants from Water Using [NTf2] and [Nf2]-Based Ionic Liquids". Applied Sciences 9, n.º 20 (14 de octubre de 2019): 4321. http://dx.doi.org/10.3390/app9204321.
Texto completoResumen
At present, pollution is one of the most important problems worldwide. Industrial growth makes it necessary to develop techniques to remove pollutant substances from water, since water is an important natural source for life. One of these techniques is liquid–liquid extraction, which is used to remove phenolic compounds from wastewaters. Volatile organic compounds are used as common extraction solvents in liquid–liquid extractions; nevertheless, some of their properties, such as toxicity and volatility, make it necessary to replace them with other less toxic solvents. In this work, the capability of four ionic liquids, based on bis(trifluoromethylsulfonyl)imide [NTf2] and bis(fluorosulfonyl)imide [Nf2] anions and different cations to remove phenolic compounds from water was studied. The phenolic compounds used in this study were phenol, o-cresol, and 2-chlorophenol, and the effects of the extraction solvent and phenol structures were analyzed. For that, a liquid–liquid extraction was carried out, and the extraction yield was determined. In general, high extraction efficiencies were obtained for all studied systems, obtaining the highest extraction efficiencies using the pyrrolidinium cation-based ionic liquids.
36
Ödkvist, Lars M., Claes Möller y Karl-Åke Thuomas. "Otoneurologic Disturbances Caused by Solvent Pollution". Otolaryngology–Head and Neck Surgery 106, n.º 6 (junio de 1992): 687–92. http://dx.doi.org/10.1177/019459989210600612.
Texto completoResumen
Subjects exposed to industrial solvents may experience vertigo and nausea. Solvents are usually volatile hydrocarbon compounds, which are Important parts of everyday life in a modern society. They may also cause neurastenia, personality changes, and reduced intellectual capacity. The syndrome that may develop was formerly named psycho-organic syndrome (POS), but in modern terminology it is called chronic toxic encephalopathy (CTE). The syndrome develops slowly, and during the first years no pathological findings will be found using various test batteries. Somewhat later, when the syndrome still might be reversible, psychometric, auditory, and otoneurologic testing may well unveil disturbances within the posterior fossa structures. Animal experiments suggest one site of effect for solvents to be within the cerebellum and brainstem regions with close relationship to the gamma-amino-butyric acid (GABA) transmission. In the otoneurologic test battery, visual suppression and smooth pursuit are of extreme value, as are some auditory tests such as discrimination of interrupted speech and cortical response audiometry using frequency glides as stimuli. Dynamic posturography and magnetic resonance Imaging (MRI) have recently proved valuable in the diagnosis. Research is needed concerning the most efficient test battery for early detection of solvent-induced lesions. During further research it is Important to unveil other toxic agents, like heavy metals and alcohol, and their damage to the central nervous system and to make comparisons between these substances and the lesions caused by hydrocarbon solvents.
37
Sharma, Arun Kumar, Meenakshi Saxena y Rashmi Sharma. "Investigation of Micellization and Viscometric Behaviour of Organo-copper Soap-urea Complexes Derived from Various Edible Oils". Current Physical Chemistry 9, n.º 2 (14 de noviembre de 2019): 123–37. http://dx.doi.org/10.2174/1877946809666190617142243.
Texto completoResumen
Background: Of-late researches in colloid chemistry are becoming increasingly important in various branches of chemistry, industry, medicine and allied fields. Copper surfactants derived from various edible oils provide an interesting area of investigation pertaining to its fundamental information regarding their colloid-chemical behaviour. Copper (II) soaps and their urea complexes in polar and non-polar solvents have gained considerable popularity due to their immense use and widespread applications such as wood preservation, foaming, wetting, biocidal, pesticidal activities, fungicidal, detergency, emulsification, paints, lubrication etc. Objective: Present work has been initiated with a view to obtain a profile due to the nature and structure of copper soap and their urea complexes with long chain fatty acids in polar and non-polar solvent, which have great significance in explaining their characteristics under different conditions. The objective of the present work is study of micellar characterizations of copper soap and their urea complexes in polar (methanol) and non-polar (benzene) solvents of varying composition and subsequent determinations of CMC using physical properties such as, viscosity. This will provide fundamental information regarding their colloid chemical behavior. Methods: The density, molar volume, viscosity, specific viscosity, and fluidity of Cu (II) soap- urea complexes derived from various edible oils in a benzene-methanol solvent system have been determined at a constant temperature of 303.15 K. Results: Results: The results were used to determine the critical micelle concentration (CMC), soap complex-solvent interactions and the effect of chain length of the surfactant molecules on various parameters. The values of the CMC in the higher volume percent of methanol are higher than those of the lower volume percent of methanol. The values of CMC for these complexes are following the order: CSoU>CSeU> CGU > CMU : This shows that there is a decrease in the CMC values with an increase of the average molecular weight of the complex. The conclusions with regard to solute-solute and solutesolvent interactions have been discussed in terms of the well-known Moulik’s and Jones- Dole equations. The effect of surfactant concentration on the viscosity of the solution in the solvent mixtures has been discussed. The observations suggested that the solvent structure breaking effect by the solute on the solvent molecules is more prominent above the CMC as compared to below the CMC. Conclusion: The vital information about the micellar behavior of synthesized molecules as a solute and their interactions with different solvents will plays an important role in various industrial and biological applications.
38
Tshilande, Neani, Liliana Mammino y Mireille K. Bilonda. "The Study of Molecules and Processes in Solution: An Overview of Questions, Approaches and Applications". Computation 12, n.º 4 (9 de abril de 2024): 78. http://dx.doi.org/10.3390/computation12040078.
Texto completoResumen
Many industrial processes, several natural processes involving non-living matter, and all the processes occurring within living organisms take place in solution. This means that the molecules playing active roles in the processes are present within another medium, called solvent. The solute molecules are surrounded by solvent molecules and interact with them. Understanding the nature and strength of these interactions, and the way in which they modify the properties of the solute molecules, is important for a better understanding of the chemical processes occurring in solution, including possible roles of the solvent in those processes. Computational studies can provide a wealth of information on solute–solvent interactions and their effects. Two major models have been developed to this purpose: a model viewing the solvent as a polarisable continuum surrounding the solute molecule, and a model considering a certain number of explicit solvent molecules around a solute molecule. Each of them has its advantages and challenges, and one selects the model that is more suitable for the type of information desired for the specific system under consideration. These studies are important in many areas of chemistry research, from the investigation of the processes occurring within a living organism to drug design and to the design of environmentally benign solvents meant to replace less benign ones in the chemical industry, as envisaged by the green chemistry principles. The paper presents a quick overview of the modelling approaches and an overview of concrete studies, with reference to selected crucial investigation themes.
39
Thamer Salman, Zeena y Hadi M.A.Abood. "Crystallized Ammonium Alum and Recovery of Ammonium Alum: Urea DES from Cellulose/DES Solution". Al-Nahrain Journal of Science 24, n.º 1 (1 de marzo de 2021): 20–23. http://dx.doi.org/10.22401/anjs.24.1.04.
Texto completoResumen
Recycling and/or recovery of solvent are of important aim in the area of environment or cost. Deep eutectic solvents (DES’s) have been widely employed in different research or industrial area. Ammonium alum: urea DES has been researched for possible applications therefore; recovery of this DES is attempted in this paper. Ammonium alum: urea DES was separated to its constituents by crystallization of ammonium alum from a solution containing cellulose. Urea was obtained by evaporation. The crystallization occurs by adding water which breaks the hydrogen bonding of DES. Water was added in a 1.25:1 volume ratio and the resulting crystals and solid materials were examined with ATR-IR and X-Ray Diffraction.
40
Sinhamahapatra, Apurba, Narottam Sutradhar, Biplab Roy, Abhijit Tarafdar, Hari C. Bajaj y Asit Baran Panda. "Mesoporous zirconium phosphate catalyzed reactions: Synthesis of industrially important chemicals in solvent-free conditions". Applied Catalysis A: General 385, n.º 1-2 (15 de septiembre de 2010): 22–30. http://dx.doi.org/10.1016/j.apcata.2010.06.016.
Texto completo
41
Ramli, Uswatun Hasanah, Idris Musa y Robert Thomas Bachmann. "Oil Yield Determination for <i>Moringa oleifera</i> Seeds Using n-Hexane or Ethanol; Extraction Time or Number of Siphons?" Materials Science Forum 1077 (15 de diciembre de 2022): 219–26. http://dx.doi.org/10.4028/p-c487vc.
Texto completoResumen
Solvent extraction is commonly used to extract oil from most seeds, including Moringa oleifera (MO). Oil extraction is a critical step in the production of cosmetics, pharmaceuticals, and other products that require the maximum amount of oil from the seed. On the other hand, MO as a coagulant need to be oil-free for coagulation performance. Therefore, optimization of oil yield is kept up to date. The extraction time, seed to solvent ratio, and particle size are the most optimised parameters reported on MO. Most Soxhlet extraction methodologies reported in the past mention a time range for extracting oil from the seed. Following the same extraction time, however, frequently results in variation in the yield of MO obtained. Because of this lack of reproducibility in oil yield, it has been demonstrated that using extraction time as a basis for monitoring the point at which maximum oil yield is achieved is not completely reliable. The range of ratios, solvent type, moisture content of the seed and the heating mantle vary from one to another. This study is focusing on oil extraction based on the number of siphons(8,16,24,32 siphons) using 2 different solvents (ethanol with a boiling point of and n-henaxe with a boiling point of) and shows that the optimum oil yield is at 16 siphons. It is also important to see when the extraction should stop for industrial scale to be cost effective. This method is then validated with two batches of MO seed for reproducibility. In addition, the use of polar solvents such as ethanol may also remove more protein and minerals from the seed, which can affect the quality and performance of the defatted MO seed in coagulation assays. Hence, EDS tests are included for preparing the suitable solvent used based on mineral removal.
42
Azzouzi, Hanane, Loubna Elhajji, Mouad Achchoub, Mohammed Benbati, Kaoutar El-Fazazi y Souad Salmaoui. "Assessment of Total Phenolic Content and Antioxidant Activity Potential of Clementine Extract Obtained by Microwave Assisted Extraction Method". Biosciences Biotechnology Research Asia 18, n.º 4 (30 de diciembre de 2021): 779–85. http://dx.doi.org/10.13005/bbra/2959.
Texto completoResumen
Citrus peels are known as rich source of bioactive compounds. Therefore, the establishment of an appropriate and innovative extraction method is a major interest to the food processing industry. The aim of this work is to assess the total phenolic content (TPC) and antioxidant activity (AA) of peels extracts prepared from five Moroccan clementine varieties. Extracts were prepared with microwave-assisted extraction (MAE) technique using acetone and methanol solvents. The evaluation of the antioxidant activity was performed by DPPH and ABTS- free radical scavenging. The extraction conditions had significant effects on total phenolic content (TPC) and antioxidant activity (AA). In fact, the highest TPC amount of clementine varieties (730.850±0.004mg GAE/100g DM) was obtained with acetone solvent for the Sidi Aissa variety. Regarding antioxidant activity, results with DPPH method showed an important antiradical and antioxidant activities for Sidi Aissa variety with methanol solvent (46.30± 1.01%) . However, ABTS method showed a good antioxidant activity for Ain Taoujdat with methanol solvent (3.02 mg/100g DM). This work provided to study the biochemical quality of Moroccan clementine extracts obtained by two microwave-assisted extraction processes in order to investigate further industrial potential uses in agro-food and pharmaceutical industries
43
Mnayer, Dima, Anne-Sylvie Fabiano-tixier, Emmanuel Petitcolas y Karine Ruiz. "Extraction of green absolute from thyme using ultrasound and sunflower oil". Resource-Efficient Technologies, n.º 1 (12 de marzo de 2017): 12–21. http://dx.doi.org/10.18799/24056529/2017/1/112.
Texto completoResumen
Absolute is the plant aroma isolate mostly used in the food and fragrance sectors. The use of organic solvents constitutes the most commonly used method for obtaining this aroma. However, this technique may leave trace amounts of solvents which are considered undesirable for these industries. In this work, a new green extraction approach was implemented using ultrasound (US) with sunflower oil (SO) as a natural solvent to produce green absolute from thyme (Thymus vulgaris). US optimal conditions for absolute yield were investigated using response surface methodology (RSM) and compared to conventional SO (SO-CV) and hexane (Hex-CV) extractions. The absolutes were analyzed by GC–MS for their chemical composition and tested for their antioxidant activities (total phenols, DPPH and frying test). Optimized conditions obtained by RSM for absolute yield were T = 50 °C, t = 22 min, P = 98W. The US using SO as solvent offers important advantages: shorter extraction time, increase of 47% in absolute yield compared to SO-CV extraction. Although the absolute obtained by hexane extraction provided improved yield (8.64 g/100 g DW), it contained around 75% of waxy materials. GC–MS analysis showed no remarkable variation of the chemical composition of the absolutes compared to those obtained by hexane extraction. Moreover, the US extraction allowed the highest recovery of monoterpene phenols thymol and carvacrol (86.2%). The absolute obtained by SO-US was free from waxes and organic solvent residues and exerted the highest antioxidant activity. Results show that ultrasound extraction using SO is a good alternative. It suggests the possibility of the production of green absolutes on pilot and industrial scale.
44
Taran, O. P., V. V. Sychev y B. N. Kuznetsov. "γ-Valerolactone as a promising solvent and basic chemical product. Catalytic synthesis from components of vegetable biomass". Kataliz v promyshlennosti 1, n.º 1-2 (18 de marzo de 2021): 97–116. http://dx.doi.org/10.18412/1816-0387-2021-1-2-97-116.
Texto completoResumen
γ-Valerolactone (GVL), which is a valuable chemical compound and a platform molecule, is considered as an intermediate product for the synthesis of chemical compounds with high added value, components of motor fuels and biopolymers. GVL is successfully used as an environmentally friendly solvent, fuel additive, fragrance and food additive. This review summarizes recent advances in the development of catalytic methods for the production of GVL from levulinic acid (LA), alkyl levulinates (AL), carbohydrates and vegetable polymers. Particular attention is paid to heterogeneous catalysts based on metals and metal oxides, which are more promising for practical application. The proposed mechanisms of processes are considered in detail, and prospects of using hydrogen-donor solvents in the production of GVL are discussed. Catalysts with the best catalytic performance were compared in terms of their productivity, which is an important parameter for industrial catalysis.
45
Delolo, Fábio G., Eduardo N. dos Santos y Elena V. Gusevskaya. "Anisole: a further step to sustainable hydroformylation". Green Chemistry 21, n.º 5 (2019): 1091–98. http://dx.doi.org/10.1039/c8gc03750g.
Texto completo
46
MCINTOSH, J. y J. J. A. HEFFRON. "106 In vitro toxicological assessment of mixtures of organic solvents of industrial importance". Biochemical Society Transactions 26, n.º 1 (1 de febrero de 1998): S59. http://dx.doi.org/10.1042/bst026s059.
Texto completo
47
Ramadhan, Darwin Riyan, Asma Nadia y Alfira Maulidyah Rahmah. "Application of Carbon Capture and Utilization (CCU) in Oil and Gas Industry to Produce Microalgae-Based Biofuels with Solvent-Captured Method". Indonesian Journal of Energy 6, n.º 2 (31 de agosto de 2023): 103–11. http://dx.doi.org/10.33116/ije.v6i2.159.
Texto completoResumen
The production process in the oil and gas industry, which is a major demand, still plays a huge role in carbon emissions, especially in the refining process. The energy and industrial sectors are responsible for more than 75% of these global CO2 emissions. This condition is an important issue regarding the effort to reduce climate change due to these emissions by implementing CCU. This article aims to examine methods of carbon capture with chemical absorption by solvents and to compose a model diagram of carbon utilization with microalgae. An extensive literature search was conducted in accordance with the scoping review methodology and the PEO framework. Our search criteria were limited to article research within the last 5 years (2017–2021). Themes found from this review included the CCU method in general, carbon capture by solvent method, type of solvent used, advantages and disadvantages, and utilization of carbon in the gas and oil industries. CCU is a model that can be offered as an alternative to reduce CO2 emissions produced by industry. The scoping review result shows the best method for carbon capture is with monoethanolamine (MEA) solvent. The flue gas from post-combustion streams into the absorption column and the solvent is added. The carbon-rich solvent is regenerated by heat to produce a clean solvent to be reused in the capture cycle. Carbon that has been absorbed by the MEA in the form of gas will be channeled through pipes to the microalgae industry as utilization of captured carbon and then converted to biofuels. It was discovered that MEA is a cost-effective solvent, efficiently captures carbon, and can be used repeatedly. However, the amine emissions from MEA are considered hazardous. The conclusion is that MEA solvent has advantages and disadvantages. Further optimization research is needed to determine the preeminent capture and separation process. Thus, it is necessary to determine the best conditions for the use of captured carbon by microalgae.
48
Demiral, H. y M. Ercengiz Yildirim. "Recovery of acetic acid from waste streams by extractive distillation". Water Science and Technology 47, n.º 10 (1 de mayo de 2003): 183–88. http://dx.doi.org/10.2166/wst.2003.0570.
Texto completoResumen
Wastes have been considered to be a serious worldwide environmental problem in recent years. Because of increasing pollution, these wastes should be treated. However, industrial wastes can contain a number of valuable organic components. Recovery of these components is important economically. Using conventional distillation techniques, the separation of acetic acid and water is both impractical and uneconomical, because it often requires large number of trays and a high reflux ratio. In practice special techniques are used depending on the concentration of acetic acid. Between 30 and 70% (w/w) acetic acid contents, extractive distillation was suggested. Extractive distillation is a multicomponent-rectification method similar in purpose to azeotropic distillation. In extractive distillation, to a binary mixture which is difficult or impossible to separate by ordinary means, a third component termed an entrainer is added which alters the relative volatility of the original constituents, thus permitting the separation. In our department acetic acid is used as a solvent during the obtaining of cobalt(III) acetate from cobalt(II) acetate by an electrochemical method. After the operation, the remaining waste contains acetic acid. In this work, acetic acid which has been found in this waste was recovered by extractive distillation. Adiponitrile and sulfolane were used as high boiling solvents and the effects of solvent feed rate/ solution feed rate ratio and solvent type were investigated. According to the experimental results, it was seem that the recovery of acetic acid from waste streams is possible by extractive distillation.
49
Alarfaj, Ahlam Abdulaziz, Rami B. H. Kacem, Lotfi Snoussi, Narcisa Vrinceanu, Mishael A. Alkhaldi, Nora O. Alzamel y Noureddine Ouerfelli. "Correlation Analysis of the viscosity Arrhenius-type equations parameters for some binary liquids mixtures". Mediterranean Journal of Chemistry 6, n.º 2 (4 de enero de 2017): 23–32. http://dx.doi.org/10.13171/mjc62/01701041808-alarfaj.
Texto completoResumen
The analysis of fluids physicochemical properties, particularly the liquids viscosity, is important for the optimization of industrial processes and products. For that, several empirical and semi-empirical equations have been proposed in the literature to study the viscosity of pure liquids and binary liquid mixtures. In this context, Messaâdi et al. have recently proposed an equation correlating the two parameters of the viscosity Arrhenius-type equation, such as the activation energy (Ea) and the pre-exponential factor (As), for 75 pure solvents. This paper aims to extend their model to binary liquid mixtures. To achieve this purpose, statistical analysis is made using data sets from the literature of some solvent binary mixtures at different compositions and temperatures. The validation of the extended Messaâdi-Dhouibi equation for binary liquid mixtures simplifies the estimation of viscous behavior and the ensuing calculations. It is very useful for engineering data which permits to estimate one non-available parameter when the second one is available.
50
Guan, Youliang, Zujin Yang, Kui Wu y Hongbing Ji. "Crystallization Thermodynamics of α-Lactose Monohydrate in Different Solvents". Pharmaceutics 14, n.º 9 (25 de agosto de 2022): 1774. http://dx.doi.org/10.3390/pharmaceutics14091774.
Texto completoResumen
It is common to find that some of the lactose in dairy powders and pharmaceutical tablets is present in the unstable amorphous state. Therefore, their crystallization thermodynamics in different solvents are particularly important. In this paper, the solubility of α-lactose monohydrate (α-LM) in 15 mono-solvents such as ethanol, isopropanol, methanol, 1-propanol, 1-butanol, 2-butanol, isobutanol, 1-pentanol, isoamylol, 1-hexanol, 1-heptanol, 1-octanol, propanoic acid, acetonitrile, and cyclohexanone was evaluated by using the gravimetric method in the temperature ranges from 274.05 K to 323.05 K at constant pressure (1 atm). In the given temperature range, the solubility of α-LM in these solvents increased with the rising of temperature, the highest solubility of α-LM was found in methanol (2.37 × 104), and the lowest was found in 1-hexanol (0.80 × 105). In addition, the increase of α-LM solubility in isopropanol was the largest. The sequence at 298.15 K was: methanol > 1-butanol > isopropanol > ethanol > 1-propanol > 1-heptanol > isobutanol > propionic acid > 1-pentanol > 1-octanol > acetonitrile > isoamylol > 2-butanol > cyclohexanone > 1-hexanol. Solvent effect analysis shows that the properties of α-LM are more important than those of solvents. The Apelblat equation, λh equation, Wilson model, and NRTL model were used to correlate the experimental values. The root-mean-square deviation (RMSD) and relative average deviation (RAD) of all models were less than 2.68 × 10−2 and 1.41 × 10−6, respectively, implying that the fitted values of four thermodynamic models all agreed well with the experimental values. Moreover, the thermodynamic properties of the dissolution process (i.e., dissolution Gibbs free energy (ΔdisG), molar enthalpy (ΔdisH), and molar entropy (ΔdisS)) for α-LM in selected solvents were determined. The results indicate that ΔdisH/(J/mol) (from 0.2551 to 6.0575) and ΔdisS/(J/mol/K) (from 0.0010 to 0.0207) of α-LM in these solvents are all positive, and the values of ΔdisH and ΔdisS. ΔdisG/(J/mol) (from −0.0184 to −0.6380) are all negative. The values were observed to decrease with rising temperatures, implying that α-LM dissolution is an endothermic, entropy-driven, and spontaneous process. The solid–liquid equilibrium data and dissolution thermodynamics of α-LM were obtained, which provide a basis for industrial production.