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1
Kurniawansyah, Firman. „Pengembangan Teknologi Berbasis Media Air Subkritis dan CO2 Bertekanan untuk Intensifikasi Proses“. Jurnal Rekayasa Proses 13, Nr. 1 (01.07.2019): 1. http://dx.doi.org/10.22146/jrekpros.41868.
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A B S T R A C TGreen solvent, an environmentally friendly solvent in form of subcritical water (SBCW) and pressurized CO2, has been used as media in process intensification. It has characteristic of having low or even zero toxicity. Hence it can simplify purification procedure. In this communication, development of technology applications of those green solvents, i.e. extraction, particle synthesis, and reaction engineering, is briefly presented. In general, studies show a positive utilization of green solvents of subcritical water and pressurized CO2. For example, in pectin extraction, yield up to 90% has been obtained when the combined solvent was used. In another application, hydrolysis using SBCW-CO2 as combined solvent has facilitated 100% conversion of pinene.Keywords: carbon dioxide; intensification process; subcritical water A B S T R A KGreen solvent, yakni pelarut yang ramah lingkungan dalam bentuk air subkritis (subcritical water, SBCW) dan CO2 bertekanan yang telah dikembangkan untuk media pemrosesan, sebagai salah satu upaya intensifikasi proses. Solven ini dikatakan ramah lingkungan karena tingkat toksisitas air subkritis maupun CO2 sangat rendah, atau bahkan tidak ada sama sekali, sehingga mempersingkat prosedur purifikasi. Pada artikel pendek ini, pengembangan aplikasi teknologi tersebut diulas sebagai telaah (review) pendek dalam teknologi pemisahan (ekstraksi), sintesis partikel, dan rekayasa reaksi. Hasil-hasil studi pada umumnya memberi konfirmasi positif tentang potensi pemakaian dua fluida ramah lingkungan, yaitu SBCW dan CO2, dalam rekayasa proses. Sebagai contoh pada studi ekstraksi pektin, proses menggunakan green solvent berhasil mencapai yield hingga 90%. Hasil serupa dapat dilihat dari konversi pinene melalui proses hidrolisis hingga mencapai 100%.Kata kunci: air subkritis; karbon dioksida; intensifikasi proses
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A. R. Rassoul, Ghiyath, und Laith S. Mahmmoud. „TREATING THE USED AUTOMOBILES OILS USING SOLVENTS“. Iraqi Journal of Chemical and Petroleum Engineering 11, Nr. 3 (30.09.2010): 9–14. http://dx.doi.org/10.31699/ijcpe.2010.3.2.
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Used automobile oils were subjected to filtration to remove solid material and dehydration to remove water, gasoline and light components by using vacuum distillation under moderate pressure, and then the dehydrated waste oil is subjected to extraction by using liquid solvents. Two solvents, namely n-butanol and n-hexane were used to extract base oil from automobile used oil, so that the expensive base oil can be reused again.The recovered base oil by using n-butanol solvent gives (88.67%) reduction in carbon residue, (75.93%) reduction in ash content, (93.73%) oil recovery, (95%) solvent recovery and (100.62) viscosity index, at (5:1) solvent to used oil ratio and (40 oC) extraction temperature, while using n-hexane solvent gives (60.25%) reduction in carbon residue, (76.54%) reduction in ash content, (89.06%) oil recovery, (94.78%) solvent recovery and (100.3) viscosity index, at (6:1) solvent to used oil ratio and (50 oC) extraction temperature.
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Shakir, Firdews, Hussein Hussein und Zeinab Abdulwahhab. „Upgrading of Sharqy Baghdad Heavy Oil via N-Hexane Solvent“. Iraqi Journal of Chemical and Petroleum Engineering 23, Nr. 3 (30.09.2022): 59–66. http://dx.doi.org/10.31699/ijcpe.2022.3.8.
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Asphaltenes are a solubility class described as a component of crude oil with undesired characteristics. In this study, Sharqy Baghdad heavy oil upgrading was achieved utilizing the solvent deasphalting approach as asphaltenes are insoluble in paraffinic solvents; they may be removed from heavy crude oil by adding N-Hexane as a solvent to create deasphalted oil (DAO)of higher quality. This method is known as Solvent De-asphalting (SDA). Different effects have been assessed for the SDA process, such as solvent to oil ratio (4-16/1 ml/g), the extraction temperature (23 ºC) room temperature and (68 ºC) reflux temperature at (0.5 h mixing time with 400 rpm mixing speed). The best solvent deasphalting results were obtained at room temperature and 12 ml/g solvents to oil ratio. As a result, the API of DAO was increased by 9.3º compared to the API of Sharqy Baghdad heavy oil. The asphaltene reduction was 61.56%. The Sulfur removal was 32.8%, the Vanadium removal was 36.48%, and the Nickel removal was 46.21%.
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Hussein, Hussein Qasim, und Ali Laith Abdulkarim. „Investigation of Binary Solvents Performance for Regeneration of Iraqi 15W- 40 Waste Lubricant“. Iraqi Journal of Chemical and Petroleum Engineering 17, Nr. 4 (30.12.2016): 83–94. http://dx.doi.org/10.31699/ijcpe.2016.4.8.
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The aim of this study was to investigate the effectiveness of binary solvent for regeneration of spent lubricating oil by extraction-flocculation process. The regeneration was investigated by bench scale experiments by using locally provided solvents (Heavy Naphtha, n-Butanol, and iso-Butanol). Solvents to used oil, mixing time, mixing speed and temperatures were studied as operating parameters. The performance on three estimated depended key parameters, namely the percentage of base oil recovered (Yield), percent of oil loss (POL), and the percent of sludge removal (PSR) were used to evaluate the efficiency of the employed binary solvent on extraction process. The best solvent to solvent ratio for binary system were 30:70 for Heavy Naphtha : n-Butanol (N:n-But) and Heavy Naphtha : iso-Butanol (N:iso-But). The optimum solvent to oil ratio or critical clarifying ratio (CCR) were 3.4, and 3.8 for N : n-But, and N : iso-But respectively. The optimized operating mixing time, mixing speed, and temperature which result in, maximum recovered base oil (87.75% and 88.88%), minimum oil losses (8.46% and 3.62%), and maximum sludge removal (5.63% and 6.12%), were (45 min, 700 rpm, 35 oC), and (30 min, 700 rpm, 35 oC ) for N:n-But, and N:Iso-But respectively.
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Hemdan, Sokaina, Asma Al Jebaly und Fatma Ali. „The Impacts of Various Media on the Electronic Spectrum of Aniline Violet“. Academic Journal of Research and Scientific Publishing 2, Nr. 24 (05.04.2021): 28–55. http://dx.doi.org/10.52132/ajrsp.e.2021.242.
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The solvent impact can be decided by Solvent polarity scales, a solvatochromic parameter that has a distinctive position of UV-Visible absorption band within the extend between 250 and 700 nm. The spectral characteristics of Aniline Violet in several solvents at room temperature were analyzed which is that the point of considering the impact of solvents on the absorption spectra of this cationic dye in organic solvent of distinctive characters. The solvent impacts on the wavenumber of the absorption band maxima (max) were talked about utilizing the taking after solvent parameters, refractive index, n, relative permittivity, ε and therefore the empirical solvent polarity ET (30), (*, and ) and (SA, SB, SP and SPd). The solute–solvent interactions were decided on the premise of multilinear solvation energy relationships concept. The fitting coefficients gotten from this analysis allowed us to estimate the contribution of each type of interactions to the total spectral shifts in solution. The set up dependences between max and the solvent parameters emphasize that the visible band of the examined molecule is influenced by both non-specific and specific solute–solvent interactions. The results appeared the solvent polarizability has major impact on the spectral shift instead of hydrogen bonding accepting ability. Catalan strategy show higher acceptable correlation than Kamlet-Taft methodology and Katritzky methodology. The dissociation constant pKa and the isosbestic point of the explored compound were shown the presence of the individual predominate ionic species was assigned by constructing distribution charts at diverse pH ranges. The results showed that the relative permittivity constant, ε, is important factor affecting on the magnitude of the dissociation constant beside the hydrogen bonding of the solvent.
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Roux, Denis C. D., Isabelle Jeacomine, Guillaume Maîtrejean, François Caton und Marguerite Rinaudo. „Characterization of Agarose Gels in Solvent and Non-Solvent Media“. Polymers 15, Nr. 9 (30.04.2023): 2162. http://dx.doi.org/10.3390/polym15092162.
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Agarose is known to form a homogeneous thermoreversible gel in an aqueous medium over a critical polymer concentration. The solid-liquid phase transitions are thermoreversible but depend on the molecular structure of the agarose sample tested. The literature has mentioned that agarose gels could remain stable in non-solvents such as acetone or ethanol. However, there has been no characterization of their behavior nor a comparison with the gels formed in a good solvent such as water. In the first step of this article, the structure was characterized using 1H and 13C NMR in both D2O and DMSO-d6 solvents. DMSO is a solvent that dissolves agarose regardless of the temperature. First, we have determined a low yield of methyl substitution on the D-galactose unit. Then, the evolution of the 1H NMR spectrum was monitored as a function of temperature during both increasing and decreasing temperature processes, ranging from 25 to 80 °C. A large thermal hysteresis was obtained and discussed, which aided in the interpretation of rheological behavior. The hysteresis of NMR signals is related to the mobility of the agarose chains, which follows the sol/gel transition depending on the chains’ association with H-bonds between water and the -OH groups of agarose for tightly bound water and agarose/agarose in chain packing. In the second step of the study, the water in the agarose gel was exchanged with ethanol, which is a non-solvent for agarose. The resulting gel was stable, and its properties were characterized using rheology and compared to its behavior in aqueous media. The bound water molecules that act as plasticizers were likely removed during the exchange process, resulting in a stronger and more brittle gel in ethanol, with higher thermal stability compared to the aqueous gel. It is the first time that such gel is characterized without phase transition when passing from a good solvent to a non-solvent. This extends the domains of application of agarose.
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Di Carmine, Graziano, Andrew P. Abbott und Carmine D'Agostino. „Deep eutectic solvents: alternative reaction media for organic oxidation reactions“. Reaction Chemistry & Engineering 6, Nr. 4 (2021): 582–98. http://dx.doi.org/10.1039/d0re00458h.
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A. Mohammed, Abdul-Halim, und Mohammed J. Yass Kheder. „The Effect of Extraction Temperature and Solvent to Oil Ratio on Viscosity Index of Mixed-medium Lubricating Oil Fraction by Using Solvents Extraction“. Iraqi Journal of Chemical and Petroleum Engineering 10, Nr. 2 (30.06.2009): 13–18. http://dx.doi.org/10.31699/ijcpe.2009.2.3.
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In this study two types of extraction solvents were used to extract the undesirable polyaromatics, the first solvent was furfural which was used today in the Iraqi refineries and the second was NMP (N-methyl-2-pyrrolidone).The studied effecting variables of extraction are extraction temperature ranged from 70 to 110°C and solvent to oil ratio in the range from 1:1 to 4:1.The results of this investigation show that the viscosity index of mixed-medium lubricating oil fraction increases with increasing extraction temperature and reaches 107.82 for NMP extraction at extraction temperature 110°C and solvent to oil ratio 4:1, while the viscosity index reaches to 101 for furfural extraction at the same extraction temperature and same solvent to oil ratio. The increase in solvent to oil ratio has a higher effect on increasing the viscosity index of lubricating oil fraction compared with extraction temperature in furfural and NMP extraction.Further more, the results show that the percentage yield of raffinate was decreased as the extraction temperature and solvent to oil ratio increases for furfural and NMP extraction.
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Shakir, Ibtehal k., und Muslim A. Qasim. „Extraction of Aromatic Hydrocarbons from Lube Oil Using Different Co-Solvent“. Iraqi Journal of Chemical and Petroleum Engineering 16, Nr. 1 (30.03.2015): 79–90. http://dx.doi.org/10.31699/ijcpe.2015.1.8.
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An investigation was conducted effect of addition co- solvent on solvent extraction process for two types of a lubricating oil fraction (spindle) and (SAE-30) obtained from vacuum distillation unit of lube oil plant of Daura Refinery. In this study two types of co-solvents ( formamide and N-methyl, 2, pyrrolidone) were blended with furfural to extract aromatic hydrocarbons which are the undesirable materials in raw lubricating oil, in order to improve the viscosity index, viscosity and yield of produced lubricating oil. The studied operating condition are extraction temperature range from 70 to 110 °C for formamide and 80 to 120 °C for N-methyl, 2, pyrrolidone, solvent to oil ratio range from 1:1 to 2:1 (wt./wt.) for furfural with formamide extraction and 1:1 to 3:1 (wt./wt.) for furfural with NMP extraction. The results of the investigation show that the viscosity index of lubricating oil fraction increases while viscosity and percentage yield of raffinate decreases with increasing extraction temperature, the solvent to oil ratio and co-solvent to furfural ratio. For formamide the best temperature were 90 °C, furfural to co-solvent ratio (60:40) and solvent to lube oil ratio (1.5:1) to get best value of viscosity index 102, viscosity 3.01 cst and 69.23 % yield. While for NMP co-solvent 110 °C extraction temperature, (2:1) solvent to lube oil ratio and (60:40) furfural to co-solvent ratio, to produce lube oil with 96 viscosity index, 9.10 cst viscosity and 68.50 yield.
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Istyami, Astri Nur, Tatang Hernas Soerawidjaja, Tirto Prakoso und Tri Ari Penia Kresnowati. „Performance of Various Organic Solvents as Reaction Media in Plant Oil Lipolysis with Plant Lipase“. Reaktor 18, Nr. 2 (24.08.2018): 71. http://dx.doi.org/10.14710/reaktor.18.2.71-75.
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Fatty acids are intermediate substances in synthesis of oleochemical products. Enzymatic technology of fatty acids production (also known as lipolysis) is now developing as potential substitution for the conventional production of fatty acid, i.e. thermal hydrolysis of triglyceride. It offers more economical process condition, low energy consumption, and minimal product degradation compared to the conventional process. This research aims to evaluate performance of various organic solvents as reaction media in lipolysis with plant latex lipase. Organic solvents observed were chloroform, n-hexane, diethyl ether, benzene, acetone, ethanol, methanol, n-heptane, and isooctane. Analysis of each organic solvent effect on lipolysis was described based on solvents properties. Conversion of lipolysis with organic solvents is 0,10-1,25 times fold compared to conversion of non-solvent lipolysis. We suggest that dielectric constant and viscosity are the two main organic solvent properties affecting lipase performance in lipolysis. Overall, n-hexane, n-heptane, and isooctane are recommended to be used as reaction media in lipolysis with plant lipase because their effects to degree of lipolysis are positive. Keywords: lipolysis; lipase; organic solvent; frangipani
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Altaee, Tariq, Sarmad A. Rashid und Marwa F. Abdul Jabbar. „Treatment of Used lubricant Oil by Solvent Extraction“. Iraqi Journal of Chemical and Petroleum Engineering 23, Nr. 1 (30.03.2022): 43–50. http://dx.doi.org/10.31699/ijcpe.2022.1.6.
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This study investigates the treatment of used lubricating oils from AL-Mussaib Gas Power Station Company-Iraq, which was treated with different extractive solvents (heptane and 2-propanol). The performance activity of these solvents in the extraction process was examined and evaluated experimentally. Operating parameters were solvent to oil ratios of (1:2, 1:4, 1:6, and 1:8), mixing time (20, 35, 50, and 65 min), temperatures (30, 40, 50, and 60 ºC), and mixing speed (500 rpm). These parameters were studied and analyzed. The quality is determined by the measuring and assessment of important characteristics specially viscosity, viscosity index, specific gravity, pour point, flash point, and ash content. The results confirm that the solvent 2-Propanol gave great proficiency with the most elevated percent of sludge removal compared with heptane. The greatest percentage of waste removal is enhanced when the solvent/oil ratio increases with optimal economic aspects. The significant characteristics of the reused lubricating oil were estimated. The outcome of the results indicates that the adjustment of the characteristics of reused oil has great effectiveness and the best working conditions for 2-Propanol (35 min, 1:6 S/O ratio, 40 ºC), and heptane (50 min, 1:6 S/O ratio, 50 ºC).
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Wulandari, Resa, Edi Pramono, Sun Theo Constan Lotebulo Ndruru, Abu Masykur, Sayekti Wahyuningsih, Aditya Muhammad Fadhilah, Ellya Syaharani, Elva Yoga Saputra und Mayzy Vanesia Insani. „Effects of Temperature, Molecular Weight, and Non-Solvent Variation on the Physical Properties of PVDF Membranes Prepared through Immersion Precipitation“. Jurnal Kimia Sains dan Aplikasi 27, Nr. 1 (06.02.2024): 35–44. http://dx.doi.org/10.14710/jksa.27.1.35-44.
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Research on porous membrane technology is proliferating, especially in the process of fabrication of membranes. Different methods in membrane fabrication can affect the physical and chemical properties of the produced membrane. This study aims to investigate the influence of temperature, molecular weight, and non-solvent type on the physical-chemical properties of PVDF membranes. The membrane was produced by the immersion precipitation method with varying PVDF molecular weights of 64 kDa, 352 kDa (Solef 1010), 534 kDa, and 573 kDa (Solef 1015); non-solvent variations of alcohol (methanol, ethanol, isopropyl alcohol, and butanol); and drying temperature variations of 40, 50, and 60°C. The produced membranes were analyzed using ATR-FTIR, XRD, TGA, DSC, and SEM, and their wettability properties were evaluated using water contact angles. The optimal drying temperature for membrane production was 60°C. The ATR-FTIR data showed that molecular weight impacted membrane structure, where PVDF MW 534 kDa membrane had the highest percentage of β phase (77.47%). Non-solvent changes also affected membrane structure; PVDF Solef 1010 with non-solvent isopropyl alcohol had the highest percentage of β phase (67.45%). This is supported by the XRD diffractogram that displayed peaks at 2θ values between 20.24° and 20.66°, indicating the presence of a phase β PVDF. The thermal analysis exhibited three stages of degradation for Solef 1010 with ethanol non-solvent and two for the other seven membranes. The degradation temperature increases with the increase in molecular weight and the difference in non-solvents. The highest thermal stability membrane was PVDF Solef 1010 with isopropyl alcohol non-solvent (430°C). SEM images showed the membrane with non-solvent isopropyl alcohol, displaying a dense sponge-like morphology. The wettability of membranes is affected by molecular weight and non-solvent type. The membrane with isopropyl alcohol non-solvent obtained the smallest contact angle (54.77°) and indicated the most wettability membrane.
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Abdul-Karim Mohammed, Abdul-Halim, und Amal Khalid Shehab Al – Rubai. „Viscosity Index Improvement of Lubricating Oil Fraction (SAE – 30)“. Iraqi Journal of Chemical and Petroleum Engineering 9, Nr. 3 (30.09.2008): 51–57. http://dx.doi.org/10.31699/ijcpe.2008.3.8.
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An investigation was conducted for the improvement of viscosity index of a lubricating oil fraction (SAE – 30) obtained from vacuum distillation unit of lube oil plant of Daura Refinery, using solvent extraction process. In this study two type of extraction solvents were used to extract the undesirable materials which reduce the viscosity index of raw lubricating oil fraction, the first solvent was furfural which is un use today in the Iraqi refineries and the second was NMP (N-methyl, 2, pyrrolidone) which is used for the first time in this work to extract the lubricating oil fraction produced from Iraqi crude oils. The studied effecting variables of extraction are extraction temperature range from 70 to 110 oC for furfural and NMP extraction, solvent to oil ratio range from 1:1 to 5:1 (wt/wt) for furfural extraction and from 0.5:1 to 2:1 (wt/wt) for NMP extraction. The results of this investigation show that the viscosity index of lubricating oil fraction increases with increasing extraction temperature and increasing the solvent to oil ratio and reaches 83 for NMP extraction at extraction temperature 110 oC and solvent to oil ratio 2:1, while the viscosity index reaches to 80 for furfural extraction at the same extraction temperature and solvent oil ratio. Higher viscosity index of lubricating oil fraction is obtained by using NMP instead of furfural under the same operating variables (extraction temperature and solvent to oil ratio). Further more, the results show that the viscosity, refractive index, and percentage yield of raffinate decreased as the extraction temperature or solvent to oil ratio increases for furfural and NMP extraction.
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WIEDERKEHR, Nadir Ana. „A model for specific interactions of manganese-phthalocyanine in protic media“. Eclética Química 24 (1999): 45–59. http://dx.doi.org/10.1590/s0100-46701999000100004.
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Extinction coefficients (e) changes of manganese phthalocyanine (Mn-Pc) were studied in different organic solvents and related to solvent polarity scales; (Kosower's values (Z), Dimroth's values (E T), donor numbers (DN) and linear solvation energy relationships (LSER) or linear free energy relationships (LFER));, theoretical molecular orbital calculations and ligand/solvent coordination processes in order to predict molecular interaction with the medium and identification of predominant intermolecular forces.
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Wiederkehr, Nadir Ana. „A model for specific interactions of manganese-phthalocyanine in protic media“. Ecletica Quimica 24, Nr. 1 (06.12.1999): 45–59. http://dx.doi.org/10.26850/1678-4618eqj.v24.1.1999.p45-59.
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Extinction coefficients (e) changes of manganese phthalocyanine (Mn-Pc) were studied in different organic solvents and related to solvent polarity scales (Kosower's values (Z), Dimroth's values (ET), donor numbers (DN) and linear solvation energy relationships (LSER) or linear free energy relationships (LFER)), theoretical molecular orbital calculations and ligand/solvent coordination processes in order to predict molecular interaction with the medium and identification of predominant intermolecular forces.
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Sabeeh, Haneen, und Basma I. Waisi Waisi. „Effect of Solvent Type on PAN–Based Nonwoven Nanofibers Membranes Characterizations“. Iraqi Journal of Chemical and Petroleum Engineering 23, Nr. 4 (30.12.2022): 43–48. http://dx.doi.org/10.31699/ijcpe.2022.4.6.
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Electrospun nanofiber membranes are employed in a variety of applications due to its unique features. the nanofibers' characterizations are effected by the polymer solution. The used solvent for dissolving the polymer powder is critical in preparing the precursor solution. In this paper, the Polyacrylonitrile (PAN)-based nanofibers were prepared in a concentration of 10 wt.% using various solvents (NMP, DMF, and DMSO). The surface morphology, porosity, and the mechanical strength of the three prepared 10 wt.% PAN-based nanofibers membranes (PAN/NMP, PAN/DMF, and PAN/DMSO) were characterized using the Scanning Electron Microscopy (SEM), Dry-wet Weights method, and Dynamic Mechanical Analyzer (DMA). Using DMF as a solvent resulted in a long, beaded, homogeneous, and smooth surface fibrous structure with an average diameter of 260 nm, which was the best among the solvents tested in this study in terms of porosity and mechanical strength.
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Tang, Christina, und Bridget T. McInnes. „Cascade Processes with Micellar Reaction Media: Recent Advances and Future Directions“. Molecules 27, Nr. 17 (31.08.2022): 5611. http://dx.doi.org/10.3390/molecules27175611.
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Reducing the use of solvents is an important aim of green chemistry. Using micelles self-assembled from amphiphilic molecules dispersed in water (considered a green solvent) has facilitated reactions of organic compounds. When performing reactions in micelles, the hydrophobic effect can considerably accelerate apparent reaction rates, as well as enhance selectivity. Here, we review micellar reaction media and their potential role in sustainable chemical production. The focus of this review is applications of engineered amphiphilic systems for reactions (surface-active ionic liquids, designer surfactants, and block copolymers) as reaction media. Micelles are a versatile platform for performing a large array of organic chemistries using water as the bulk solvent. Building on this foundation, synthetic sequences combining several reaction steps in one pot have been developed. Telescoping multiple reactions can reduce solvent waste by limiting the volume of solvents, as well as eliminating purification processes. Thus, in particular, we review recent advances in “one-pot” multistep reactions achieved using micellar reaction media with potential applications in medicinal chemistry and agrochemistry. Photocatalyzed reactions in micellar reaction media are also discussed. In addition to the use of micelles, we emphasize the process (steps to isolate the product and reuse the catalyst).
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Sharma, Shivika, und Shamsher S. Kanwar. „Organic Solvent Tolerant Lipases and Applications“. Scientific World Journal 2014 (2014): 1–15. http://dx.doi.org/10.1155/2014/625258.
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Lipases are a group of enzymes naturally endowed with the property of performing reactions in aqueous as well as organic solvents. The esterification reactions using lipase(s) could be performed in water-restricted organic media as organic solvent(s) not only improve(s) the solubility of substrate and reactant in reaction mixture but also permit(s) the reaction in the reverse direction, and often it is easy to recover the product in organic phase in two-phase equilibrium systems. The use of organic solvent tolerant lipase in organic media has exhibited many advantages: increased activity and stability, regiospecificity and stereoselectivity, higher solubility of substrate, ease of products recovery, and ability to shift the reaction equilibrium toward synthetic direction. Therefore the search for organic solvent tolerant enzymes has been an extensive area of research. A variety of fatty acid esters are now being produced commercially using immobilized lipase in nonaqueous solvents. This review describes the organic tolerance and industrial application of lipases. The main emphasis is to study the nature of organic solvent tolerant lipases. Also, the potential industrial applications that make lipases the biocatalysts of choice for the present and future have been presented.
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Soares, Maria I. L., Ana L. Cardoso und Teresa M. V. D. Pinho e Melo. „Diels–Alder Cycloaddition Reactions in Sustainable Media“. Molecules 27, Nr. 4 (15.02.2022): 1304. http://dx.doi.org/10.3390/molecules27041304.
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Diels–Alder cycloaddition reaction is one of the most powerful strategies for the construction of six-membered carbocyclic and heterocyclic systems, in most cases with high regio- and stereoselectivity. In this review, an insight into the most relevant advances on sustainable Diels–Alder reactions since 2010 is provided. Various environmentally benign solvent systems are discussed, namely bio-based derived solvents (such as glycerol and gluconic acid), polyethylene glycol, deep eutectic solvents, supercritical carbon dioxide, water and water-based aqueous systems. Issues such as method’s scope, efficiency, selectivity and reaction mechanism, as well as sustainability, advantages and limitations of these reaction media, are addressed.
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Zakerhamidi, M. S., S. M. Seyed Ahmadian und R. Kian. „The specific and nonspecific solvatochromic behavior of Sudan dyes in different solvents“. Canadian Journal of Chemistry 93, Nr. 6 (Juni 2015): 639–47. http://dx.doi.org/10.1139/cjc-2014-0489.
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Absorption and fluorescence spectra of some Sudan dyes (Sudan III, Sudan IV, and Sudan Black B) were recorded in various solvents in the range of 300–800 nm at room temperature. The solvatochromic behavior of these substances and their solvent–solute interactions were analyzed by means of the linear solvation energy relationship concept suggested by Kamlet and Taft. The obtained results express the effect of solvation on the tautomerism and molecular configuration (geometry) of Sudan dyes in solvent media. Furthermore, analysis of solvent–solute interactions suggests different forms of resonance structures of Sudan dyes in polar and low-polar solvents.
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Rosyada, Amrina, Sri Sugiarti und Irma Herawati Suparto. „Synthesis of Carbon Dot Nanoparticles (C-Dot) from Seeds and Seedpods of Kesumba Keling (Bixa orellana) using Hydrothermal and Solvothermal Methods“. Jurnal Kimia Sains dan Aplikasi 26, Nr. 6 (31.08.2023): 204–10. http://dx.doi.org/10.14710/jksa.26.6.204-210.
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C-dot is a 0-dimensional nanoparticle with photoluminescence properties and can be synthesized from plants, such as the Kesumba Keling plant. Kesumba Keling contains a red pigment sourced from the bixin and norbixin dyes containing functional groups like ‒COOH and ‒COO‒. These functional groups are anticipated to enhance the luminescence intensity produced by C-dot. This research focuses on synthesizing C-dots from Kesumba Keling seeds and seedpods using hydrothermal and solvothermal methods. It also involves an analysis of how different solvents and passivation agents affect the luminescence of C-dots, along with a comparison of the resulting fluorescent colors. The highest yield, at 73.26%, was achieved when using Kesumba Keling seedpods and ethanol as the solvent without adding urea. Furthermore, C-dots synthesized using ethanol as the solvent display a stronger luminescent glow compared to those produced using double-distilled water as the solvent. Additionally, all C-dots synthesized in this study emit a blue luminescence. Characterizing C-dots using a UV-Vis spectrophotometer reveals absorption peaks at two different wavelengths: 260‒280 nm and 320‒340 nm. These absorption peak results align with C-dot characteristics, as confirmed by Fourier transform infrared spectrophotometry. When comparing the intensity of C-dots, those derived from Kesumba Keling peel using the double-distilled water solvent with the addition of urea exhibit a higher intensity (measuring at 0.99) than C-dots obtained from Kesumba Keling peel using ethanol as a solvent with added urea. The solvothermal method is deemed the most effective for C-dot synthesis, as it yields the highest luminescence intensity, accompanied by an emission wavelength shift to 491.65 nm.
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Clough, Matthew T. „Organic electrolyte solutions as versatile media for the dissolution and regeneration of cellulose“. Green Chemistry 19, Nr. 20 (2017): 4754–68. http://dx.doi.org/10.1039/c7gc01776f.
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Organic electrolyte solutions – mixtures of a (room-temperature) ionic liquid with a neutral, organic, polar co-solvent – are attracting increasing attention as solvents for the regeneration and derivatisation of cellulose.
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Gu, Tongnian, Mingliang Zhang, Ting Tan, Jia Chen, Zhan Li, Qinghua Zhang und Hongdeng Qiu. „Deep eutectic solvents as novel extraction media for phenolic compounds from model oil“. Chem. Commun. 50, Nr. 79 (2014): 11749–52. http://dx.doi.org/10.1039/c4cc04661g.
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Deep eutectic solvents (DESs) as a new kind of green solvent were used for the first time to excellently extract phenolic compounds from model oil. It was also proved that DES could be used to extract other polar compounds from non-polar or weakly-polar solvents by liquid-phase microextraction.
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Chowdhury, Somnath, Prajna Mukherjee, Monoj Das und 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, Nr. 10 (Oktober 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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Kushner, M. A., T. S. Seliverstova und L. G. Matusevich. „Acid Hydrolysis of Glycosyl–Glycose Bond Disaccharides in Water–Organic Media“. Журнал физической химии 97, Nr. 3 (01.03.2023): 363–69. http://dx.doi.org/10.31857/s0044453723030160.
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Kinetic parameters (rate constants, energies and entropies of activation) of the acid-catalytic hydrolysis of reducing disaccharides cellobiose and lactose are determined in a wide range of mixtures of water and organic solvents (dioxane, acetone, DMSO, and acetic acid). It is shown that raising the content of the organic solvent accelerates the hydrolysis of the glycosidic bonds in different ways. The effect solvents have on the rate and mechanism of the studied reaction is discussed on the basis of solvation concepts.
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Torres, Eduardo, Raunel Tinoco und Rafael Vazquez-Duhalt. „Biocatalytic oxidation of polycyclic aromatic hydrocarbons in media containing organic solvents“. Water Science and Technology 36, Nr. 10 (01.11.1997): 37–44. http://dx.doi.org/10.2166/wst.1997.0354.
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Lignin peroxidase, cytochrome c and haemoglobin were tested for oxidation of polycyclic aromatic hydrocarbon (PAH) in the presence of hydrogen peroxide. The reaction mixture Contained water-miscible organic solvents in order to reduce the mass transfer limitation of hydrophobic substrates. The reaction products from all three haemoproteins were mainly quinones, suggesting the same oxidation mechanism for the three biocatalysts. The haeme prosthetic group must have located in a protein environment for it to catalyze these reactions, and only certain types of protein environment are able to induce this type of haemebased catalytic activity. The solvent hydrophobicity is a factor affecting the biocatalysis in organic media. Substrate partitioning between the active site (haeme) and the bulk solvent is the main factor of the biocatalytic behaviour in organic solvent mixtures. Site-directed mutagenesis of yeast cytochrome c significantly altered the kinetic behaviour of the protein. The Gly82;Thr 102 variant was 10 times more active and showed a catalytic efficiency 10-fold greater than the wild-type iso-1-cytochrome c. These results suggest that it is possible to design a new biocatalyst for environmental purposes.
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Dwamena, Amos K. „Recent Advances in Hydrophobic Deep Eutectic Solvents for Extraction“. Separations 6, Nr. 1 (12.02.2019): 9. http://dx.doi.org/10.3390/separations6010009.
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In the over 1,800 articles published since their inception in 2001, most deep eutectic solvents (DES) synthesized have been hydrophilic. The low cost, low toxicity, and bioavailability of DES make the solvent ‘green’ and sustainable for diverse applications. Conversely, the hydrophilicity of DES limits their practical application to only polar compounds, which is a major drawback of the solvent. For the past three years, hydrophobic deep eutectic solvents (HDES) have emerged as an alternative extractive media capable of extracting non-polar organic and inorganic molecules from aqueous environments. Due to the infancy of HDES, for the first time, this mini-review summarizes the recent developmental advances in HDES synthesis, applications, challenges, and future perspectives of the solvent. In the future, it is believed HDES will replace the majority of toxic organic solvents used for analytical purposes.
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Wang, Lei, Xianying Fang, Yang Hu, Yiwei Zhang, Zhipeng Qi, Jie Li und Linguo Zhao. „Efficient extraction of bioactive flavonoids from Celtis sinensis leaves using deep eutectic solvent as green media“. RSC Advances 11, Nr. 29 (2021): 17924–35. http://dx.doi.org/10.1039/d1ra01848e.
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In recent years, deep eutectic solvent (DES) has attracted comprehensive attention on the extraction of natural products, and is regarded as an alternative to traditional organic solvents for the environmental advantages.
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Cochrane, A. R., C. Idziak, W. J. Kerr, B. Mondal, L. C. Paterson, T. Tuttle, S. Andersson und G. N. Nilsson. „Practically convenient and industrially-aligned methods for iridium-catalysed hydrogen isotope exchange processes“. Org. Biomol. Chem. 12, Nr. 22 (2014): 3598–603. http://dx.doi.org/10.1039/c4ob00465e.
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The use of alternative solvents in the iridium-catalysed hydrogen isotope exchange reaction with developing phosphine/NHC Ir(i) complexes has identified reaction media which are more widely applicable than the commonly employed chlorinated solvent, dichloromethane.
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Nevěčná, Taťjana, Vojtěch Bekárek und Oldřich Pytela. „A Study of Effects of Temperature and Medium on Reaction of Triethylamine with Ethyl Bromide“. Collection of Czechoslovak Chemical Communications 59, Nr. 6 (1994): 1384–91. http://dx.doi.org/10.1135/cccc19941384.
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The rate constants of reaction of triethylamine with ethyl bromide have been measured in 13 solvents at the temperatures of 293, 313, 333, and 373 K. The activation entropies in the individual solvents increase when going from nonpolar to dipolar aprotic and polar protic solvents, which is explained by dominant solvation of the basic triethylamine and by formation of highly ordered associates without solvent in the activated complex in nonpolar solvent media. No isokinetic relationship has been found between the activation entropy and activation enthalpy, which indicates different solvent effects on the two quantities. The activation enthalpy and entropy of the reaction investigated are close to those of the reaction of triethylamine with ethyl iodide. Three methods have been used to evaluate the effect of medium at all the temperatures, their success being decreased in the order: Pytela's method - Kamlet-Taft - Koppel-Palm. Irrespective of the temperature, all the methods indicate that the reaction is accelerated by the solvent polarity, the significance of other effects being reflected differently depending on the temperature and the correlation equation used. A complex evaluation involving also the interpretation of the entropy and enthalpy components by means of empiric solvent parameters has shown that the resulting Gibbs energy represents a superposition of different effects of solvents on the two thermodynamic quantities, the solvent effect upon the activation entropy being predominant at the higher temperatures.
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Zou, Wei, und Yongan Gu. „Solvent Exsolution and Liberation from Different Heavy Oil–Solvent Systems in Bulk Phases and Porous Media: A Comparison Study“. Energies 17, Nr. 10 (09.05.2024): 2287. http://dx.doi.org/10.3390/en17102287.
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In this paper, experimental and numerical studies were conducted to differentiate solvent exsolution and liberation processes from different heavy oil–solvent systems in bulk phases and porous media. Experimentally, two series of constant-composition-expansion (CCE) tests in a PVT cell and differential fluid production (DFP) tests in a sandpacked model were performed and compared in the heavy oil–CO2, heavy oil–CH4, and heavy oil–C3H8 systems. The experimental results showed that the solvent exsolution from each heavy oil–solvent system in the porous media occurred at a higher pressure. The measured bubble-nucleation pressures (Pn) of the heavy oil–CO2 system, heavy oil–CH4 system, and heavy oil–C3H8 system in the porous media were 0.24 MPa, 0.90 MPa, and 0.02 MPa higher than those in the bulk phases, respectively. In addition, the nucleation of CH4 bubbles was found to be more instantaneous than that of CO2 or C3H8 bubbles. Numerically, a robust kinetic reaction model in the commercial CMG-STARS module was utilized to simulate the gas exsolution and liberation processes of the CCE and DFP tests. The respective reaction frequency factors for gas exsolution (rffe) and liberation (rffl) were obtained in the numerical simulations. Higher values of rffe were found for the tests in the porous media in comparison with those in the bulk phases, suggesting that the presence of the porous media facilitated the gas exsolution. The magnitudes of rffe for the three different heavy oil–solvent systems followed the order of CO2 > CH4 > C3H8 in the bulk phases and CH4 > CO2 > C3H8 in the porous media. Hence, CO2 was exsolved from the heavy oil most readily in the bulk phases, whereas CH4 was exsolved from the heavy oil most easily in the porous media. Among the three solvents, CH4 was also found most difficult to be liberated from the heavy oil in the DFP test with the lowest rffl of 0.00019 min−1. This study indicates that foamy-oil evolution processes in the heavy oil reservoirs are rather different from those observed from the bulk-phase tests, such as the PVT tests.
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Minò, Antonio, Giuseppe Cinelli, Francesco Lopez und Luigi Ambrosone. „Optical Behavior of Nile Red in Organic and Aqueous Media Environments“. Applied Sciences 13, Nr. 1 (03.01.2023): 638. http://dx.doi.org/10.3390/app13010638.
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A simple model is proposed to calculate the dimerization constant of a dye in non-aqueous solvents. Alkan-1ols of the formula H–(CH2)n–OH are used to study the spectroscopic behavior of Nile Red dye. The number n varied from 1 to 8 to modulate the medium hydrophobicity. Generally, Nile red is used to localize lipid droplets within cells. This molecule is non-fluorescent in water and other polar solvents but undergoes fluorescence enhancement and large absorption and emission blue shifts in non-polar environments. The calculated equilibrium constants suggest that the aggregation process is solvent-assisted. The absorption and fluorescence emission spectra reveal a marked red shift, which is studied by breaking the wavelength of the maximum band into two terms, showing the contribution of the solvent and the effect of the dye concentration. Both contributions were investigated as a function of the number n, and it was found that alkan-1ols with large n tend to aggregate and produce a smaller red shift. Conversely, it was also noticed that short-chain alkan-1ols stabilize the excited state of the dye via H-bond and the red shift increases. The hydrophilicity of the medium was found to be modulated by adding pure water, in a controlled way, to the binary systems dye–H–(CH2)n–OH (n = 1–8). The quantification of solvent hydrophilicity is described with the ratio R = water moles/alcohol moles. From this investigation, we realized that the absorption spectra values are strictly connected with the R parameter. In this context, we realized that fluorescence emission spectra allow us to determine the adjustable parameters.
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Danilchuk, Yulia V. „Thermal effect of carbohydrate dissolution in aqueous-organic media“. Health, Food & Biotechnology 2, Nr. 4 (18.09.2021): 49–59. http://dx.doi.org/10.36107/hfb.2020.i4.s77.
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This work is devoted to the theoretical substantiation of connection of temperature dependence of the solubility of carbohydrates with thermal effect of their dissolution in the water-containing organic solvents that is of great importance for optimization of the technology of their extraction from plant raw materials and further purification and separation by recrystallization. The dependence of the solubility of fructose, glucose, sucrose, and maltose in aqueous isopropanol and acetone at temperatures of 298 К (25 оС) and 275 К (2 оС) from water content in a solvent was studied. The constancy of the mechanism of solubility of carbohydrates in these environments in the given temperature interval is experimentally proved. For the first time based on the equation of Vant-Goff the logical connection of temperature dependence of solubility and thermal effect of solubility of carbohydrates is strictly grounded. The values of the thermal effect that are determined by the experimental data allow calculating the solubility of the studied carbohydrates in the aqueous–organic solvent of different concentration in the temperature range from 2оС to 25 оС. It has been established that the main contribution to the thermal effect of dissolving carbohydrates is the hydration process. Solvation by molecules of organic solvent practically does not change the value of the specified thermal effect. The significance of determined temperature dependences of the solubility of fructose, glucose and maltose is shown to optimize the technological conditions for the separation of glucose-fructose and glucose-maltose syrups by selective crystallization.
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Suljkanović, Mersiha, Jasmin Suljagić, Edita Bjelić, Ante Prkić und Perica Bošković. „Chemical Characterization of Terpene-Based Hydrophobic Eutectic Solvents and Their Application for Pb(II) Complexation during Solvent Extraction Procedure“. Molecules 29, Nr. 9 (03.05.2024): 2122. http://dx.doi.org/10.3390/molecules29092122.
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Solvents prepared from natural terpenes (menthol and thymol), as H-bond acceptors, and a series of organic acids (chain lengths of 8, 10, and 14 C atoms), as H-bond donors, were characterized and tested as reaction media for liquid–liquid extraction purposes. Due to their high hydrophobicity, they seem to be promising alternatives to conventional (nonpolar and toxic) solvents, since they possess relatively less toxic, less volatile, and consequently, more environmentally friendly characteristics. Assuming that the equilibrium is established between solvent and analyte during a ligandless procedure, it can be concluded that those nonpolar solvents can efficiently extract nonpolar analytes from the aqueous environment. Previous investigations showed a wide range of applications, including their use as solvents in extractions of metal cations, small molecules, and bioactive compounds for food and pharmaceutical applications. In this work, hydrophobic solvents based on natural terpenes, which showed chemical stability and desirable physicochemical and thermal properties, were chosen as potential reaction media in the liquid–liquid extraction (LLE) procedure for Pb(II) removal from aqueous solutions. Low viscosities and high hydrophobicities of prepared solvents were confirmed as desirable properties for their application. Extraction parameters were optimized, and chosen solvents were applied. The results showed satisfactory extraction efficiencies in simple and fast procedures, followed by low solvent consumption. The best results (98%) were obtained by the thymol-based solvent, thymol–decanoic acid (Thy-DecA) 1:1, followed by L-menthol-based solvents: menthol–octanoic acid (Men-OctA) 1:1 with 97% and menthol–decanoic acid (Men-DecA) 1:1 with 94.3% efficiency.
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Parsons, Brendon A., Olivia Lin Smith, Myeong Chae und Veljko Dragojlovic. „Properties of PTFE tape as a semipermeable membrane in fluorous reactions“. Beilstein Journal of Organic Chemistry 11 (09.06.2015): 980–93. http://dx.doi.org/10.3762/bjoc.11.110.
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In a PTFE tape phase-vanishing reaction (PV-PTFE), a delivery tube sealed with PTFE tape is inserted into a vessel which contains the substrate. The reagent diffuses across the PTFE tape barrier into the reaction vessel. PTFE co-polymer films have been found to exhibit selective permeability towards organic compounds, which was affected by the presence of solvents. In this study, we attempted to establish general trends of permeability of PTFE tape to different compounds and to better describe the process of solvent transport in PV-PTFE bromination reactions. Though PTFE tape has been reported as impermeable to some compounds, such as dimethyl phthalate, solvent adsorption to the tape altered its permeability and allowed diffusion through channels of solvent within the PTFE tape. In this case, the solvent-filled pores of the PTFE tape are chemically more akin to the adsorbed solvent rather than to the PTFE fluorous structure. The solvent uptake effect, which was frequently observed in the course of PV-PTFE reactions, can be related to the surface tension of the solvent and the polarity of the solvent relative to the reagent. The lack of pores in bulk PTFE prevents solvents from altering its permeability and, therefore, bulk PTFE is impermeable to most solvents and reagents. However, bromine, which is soluble in liquid fluorous media, diffused through the bulk PTFE. A better understanding of the PTFE phase barrier will make it possible to further optimize the PV-PTFE reaction design.
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Khokarale, Santosh Govind, Piotr Jablonski, Dariush Nikjoo, Van Minh Dinh, Ola Sundman, Knut Irgum und Jyri-Pekka Mikkola. „Poly (Vinylidene Difluoride) Polymer in 1-Ethyl-3-methylimidazolium Acetate and Acetic Acid Containing Solvents: Tunable and Recoverable Solvent Media to Induce Crystalline Phase Transition and Porosity“. Sustainable Chemistry 3, Nr. 4 (29.10.2022): 455–74. http://dx.doi.org/10.3390/suschem3040028.
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In this report, 1-ethyl-3-methylimidazolium acetate, [EMIM][AcO] ionic liquid (IL) and acetic acid (AA) comprised solvents were used for the thermal treatment of poly (vinylidene difluoride), PVDF. Here, besides the various combinations of IL and AA in solvents, the pure IL and AA were also applied as a solvent upon thermal treatments. The samples obtained after the treatment were analysed for structural and crystalline phase changes, porosity, and molecular weight distribution with various analytical techniques. The Kamlet-Taft parameters measurement of the IL and AA containing solvents with different solvatochromic dyes was also performed to examine their solvent properties and correlate with the properties of the treated PVDF materials. The treatment of PVDF with pure IL results in the formation of highly carbonaceous material due to extensive dehydroflurination (DHF) as well as possibly successive cross-linking in the polymer chains. Upon IL and AA combined solvent treatment, the neat PVDF which composed of both α- and β crystalline phases was transformed to porous and β-phase rich material whereas in case of pure AA the non-porous and pure α-phase polymeric entity was obtained. A combined mixture of IL and AA resulted in a limited the DHF process and subsequent cross-linking in the polymer chains of PVDF allowed the formation of a porous material. It was observed that the porosity of the thermally treated materials was steadily decreasing with increase in the amount of AA in solvents composition and solvent with an AA:IL mole ratio of 2:1 resulted in a PVDF material with the highest porosity amongst the applied solvents. A recovery method for the IL and AA combined solvent after the thermal treatment of PVDF was also established. Hence, with varying the type of solvents in terms of composition, the highly carbonaceous materials as well as materials with different porosities as well as crystalline phases can be obtained. Most importantly here, we introduced new IL and AA containing recoverable solvents for the synthesis of porous PVDF material with the electroactive β-phase.
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Noritomi, Hidetaka. „Effect of Solvent on Catalysis of Protease Adsorbed on Biochar in Organic Media“. Journal of Materials Science Research 7, Nr. 4 (28.09.2018): 46. http://dx.doi.org/10.5539/jmsr.v7n4p46.
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We have found that the adsorption immobilization of the serine protease α-chymotrypsin (Alpha-CT) onto bamboo charcoal powder (BCP), which is a kind of biochar, improves the transesterification rate of N-acetyl-L-tyrosine ethyl ester (N-Ac-Tyr-OEt) with n-butanol (BuOH) in 9 organic solvents. Organic solvents strongly affected the catalysis of BCP-adsorbed Alpha-CT. The transesterification rate of BCP-adsorbed Alpha-CT was much superior to that of free Alpha-CT in every organic solvent. Especially, the transesterification rate of BCP-adsorbed Alpha-CT was about 760 times higher than that of free α-CT in n-butyl acetate.
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Safaei-Ghomi, Javad, und Ali Ghasemzadeh. „Synthesis of some 3,5-diarylisoxazoline derivatives in ionic liquids media“. Journal of the Serbian Chemical Society 77, Nr. 6 (2012): 733–39. http://dx.doi.org/10.2298/jsc110831001s.
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Biologically active isoxazoline derivatives were efficiently synthesized in excellent yields and in less reaction time using mild, effective and environmentally friendly butylmethylimidazolium bromide as solvent and catalyst. By use of this catalyst isoxazoline derivatives are produced via cyclization reaction of chalcone and hydroxylamine hydrochloride in ionic liquids media. The separation of the product was facile and the catalyst could be separated and recycled. Our method is very quick, safe and avoids the use of hazardous and expensive reagents and solvents.
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Zhao, Hua, Caden Martin, Gary Baker und Katie Mitchell-Koch. „(Invited) Functionalized Water-Mimicking Ionic Liquids for Biocatalysis“. ECS Meeting Abstracts MA2022-02, Nr. 55 (09.10.2022): 2116. http://dx.doi.org/10.1149/ma2022-02552116mtgabs.
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Enzyme activity in organic solvents is usually much lower than its performance in aqueous media. To develop water-mimicking environment for the enzyme, we designed ionic liquids functionalized with tert-alcohol (as hydrogen-bond donor) and ether groups (as hydrogen-bond acceptors). These “water-like” ionic media have high thermal stability and low viscosities, and produced higher lipase and protease activities and stabilities than some enzyme-compatible organic solvents (such as tert-butanol and diisopropyl ether) and conventional ionic liquids (e.g., [BMIM][Tf2N]) during transesterification reactions under low water contents. In addition, these unique ionic solvents are found suitable media for asymmetric synthesis. Our experimental and MD simulations data illustrate the interactions between these water-mimicking solvent molecules and the enzyme.
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Priyanta, Riswanda Dwiky, Meitini Wahyuni Proborini und Anak Agung Raka Dalem. „Phosphate Solvent Fungi Exploration and Identification in West Bali National Park Forest Area“. Metamorfosa: Journal of Biological Sciences 6, Nr. 1 (02.08.2019): 131. http://dx.doi.org/10.24843/metamorfosa.2019.v06.i01.p21.
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Research on the exploration and identification of phosphate solvent fungi has never been carried out in West Bali National Park (TNBB), therefore researchers aims to explore and identify microscopic fungi to be used as phosphate solvent fungi which later will be taken from each plant soil samples (Lantana camara) that the presence is very common in TNBB. The research was implemented in two stages. The first stage is exploration of soil fungi in the field (TNBB) and identification of fungal species and the second stage is the phosphate solvent fungus test on Pikovskaya media. The results of the identification of the fungi obtained as follow: Aspergillus niger, Aspergillus bertholletius, Aspergillus flavus, Aspergillus isolate 4, Aspergillus isolate 5, Penicillium citrinum, and Trichoderma amazonicum. From the entire types of fungi obtained, there are onlybfour fungi that have the potential as phosphate solvents, namely Aspergillus niger, Aspergillus flavus, Aspergillus bertholletius and Penicillium citrinum with the presence of clear zones on Pikovskaya media. Fungi that has the best potential in the process of phosphate dissolution is Aspergillus niger.
Key words: Rhizosfer, Lantana camara, clear zone, phosphate solvent fungus
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Basnet, Nabin, und Ajaya Bhattarai. „Conductometric study of nickel chloride in ethanol-water mixed solvent media at various temperatures“. BIBECHANA 12 (20.12.2014): 128–34. http://dx.doi.org/10.3126/bibechana.v12i0.11789.
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The conductivity measurement of nickel chloride has been done in binary solvent of the ethanol-water system. The different percentage of ethanol including 10, 20, 30, 40, 50, 60, 70, 80, 90 and 100 (v/v) has been chosen as binary solvents. The concentration of the electrolyte in the prepared solutions varies from 0.008 to 0.1 mol.l-1 for temperatures 298.15 K, 303.15 K and 308.15 K. The conductivity of the electrolyte decreases with increase in ethanol content in the solvent at a particular temperature, which is due to the decrease in dielectric constant of the medium. The conductivity increases with increase in temperature and concentration, due to increase in mobility of ions and number of ions from observed electrolyte respectively. DOI: http://dx.doi.org/10.3126/bibechana.v12i0.11789BIBECHANA 12 (2015) 128-134
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Batchelor, Stephen N., und John Oakes. „New solvent scale applicable to microheterogeneous media“. Journal of Physical Organic Chemistry 18, Nr. 9 (2005): 899–900. http://dx.doi.org/10.1002/poc.961.
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Fletcher, Kristin A., Carmen E. Hernández, Lindsay E. Roy, Karen S. Coym und William E. Acree, Jr. „Solubility of diphenyl sulfone in organic nonelectrolyte solvents. Comparison of observed versus predicted values based upon the general solvation model“. Canadian Journal of Chemistry 77, Nr. 7 (01.07.1999): 1214–17. http://dx.doi.org/10.1139/v99-116.
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Experimental solubilities are reported for diphenyl sulfone dissolved in 8 alkane, 10 alcohol, and in aqueous solvent media at 25°C. Results of these measurements are used to test the predictive ability of the general solvation model log CA,orgsat/CA,aqsat = c + rR2 + sπ2H + aΣα2H + bΣβ2H + vVxwhere CA,orgsat and CA,aqsat refer to the solute solubility in the organic solvent and in water, respectively, R2 is the solute's excess molar refraction, Vx is the McGowan characteristic volume of the solute, π2H denotes the solute's dipolarity/ polarizability, and Σα2H and Σβ2H are the overall hydrogen-bond acidity and basicity descriptors for the solute. The remaining symbols in the above expression are known solvent coefficients, which have been determined previously through regressional analysis of published organic solvent - water partition coefficient and vapor-liquid equilibrium data. Computations show that the general solvation model predicts the solubility behavior of diphenyl sulfone in the 11 organic solvents for which predictions could be made to within an overall average absolute deviation of about ±20%. Key words: diphenyl sulfone solubilities, organic solvents, solubility predictions, general solvation model.
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Karalkeviciene, Rasa, Eva Raudonyte-Svirbutaviciene, Justina Gaidukevic, Aleksej Zarkov und Aivaras Kareiva. „Solvothermal Synthesis of Calcium-Deficient Hydroxyapatite via Hydrolysis of α-Tricalcium Phosphate in Different Aqueous-Organic Media“. Crystals 12, Nr. 2 (13.02.2022): 253. http://dx.doi.org/10.3390/cryst12020253.
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In the present work, the effects of various organic solvents (solvent nature and fraction within the solution) and solvothermal conditions on the formation of calcium-deficient hydroxyapatite (CDHA) via hydrolysis of α-tricalcium phosphate (α-TCP) are investigated. The wet precipitation method is applied for α-TCP synthesis, and the hydrolysis reaction is performed in solutions with different water-to-organic solvent ratios under solvothermal conditions at 120 °C for 3 h and at 200 °C for 5 h. Ethyl alcohol, isopropyl alcohol, and butyl alcohol did not inhibit the hydrolysis of α-TCP, while methyl alcohol and ethylene glycol have a more prominent inhibitory effect on the hydrolysis, hence the formation of single-phased CDHA. From all the solvents analysed, ethylene glycol has the highest impact on the sample morphology. Under certain water to ethylene glycol ratios and solvothermal conditions, samples containing a significant fraction of rods are obtained. However, samples prepared with ethylene glycol are characterised by a particularly low BET surface area.
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Svigelj, Rossella, Fabiola Zanette und Rosanna Toniolo. „Electrochemical Evaluation of Tyrosinase Enzymatic Activity in Deep Eutectic Solvent and Aqueous Deep Eutectic Solvent“. Sensors 23, Nr. 8 (12.04.2023): 3915. http://dx.doi.org/10.3390/s23083915.
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The use of green, inexpensive, and biodegradable deep eutectic solvents as nonaqueous solvents and electrolytes could be a useful way to potentially improve the enzyme biosensor performance as well as a profitable strategy to extend their use in the gas phase. However, enzyme activity in these media, although fundamental for their implementation in electrochemical analysis, is still almost unexplored. In this study, an electrochemical approach was employed to monitor tyrosinase enzyme activity in a deep eutectic solvent. This study was performed in a DES consisting of choline chloride (ChCl) as a hydrogen bond acceptor (HBA) and glycerol as a hydrogen bond donor (HBD), while phenol was chosen as the prototype analyte. The tyrosinase enzyme was immobilized on a gold-nanoparticle-modified screen-printed carbon electrode, and its activity was monitored following the reduction current of orthoquinone produced by the tyrosinase biocatalysis of phenol. This work represents a first step toward the realization of green electrochemical biosensors capable of operating in both nonaqueous and gaseous media for the chemical analysis of phenols.
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Ganesan, Mahendiraprabu, Nirmala Vedamanickam und Selvarengan Paranthaman. „Studies of intramolecular H-bond interactions and solvent effects in the conformers of glycolic acid — A quantum chemical study“. Journal of Theoretical and Computational Chemistry 17, Nr. 01 (Februar 2018): 1850009. http://dx.doi.org/10.1142/s0219633618500098.
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In this work, density functional theory is applied to understand the conformational stability and solvent effects on glycolic acid conformers in different solvents. In addition, the role of intramolecular hydrogen bond (H-bond) interactions in the stability of conformers are investigated. The molecular geometries of selected conformers are optimized using B3LYP and PBE0 functionals with 6-311[Formula: see text]G(d,p) basis set. The effects of solvent on the geometrical parameters, relative stability, dipole moment, chemical hardness, chemical potential, etc. are studied for the conformers of glycolic acid. Our calculations show that the order of stability of the SSC and AAT conformers does not change in liquid phase. However, the energy of SSC and AAT conformers is very close to each other in water media. In water media, strong intramolecular H-bond interaction is present in AAT conformer which causes the energy of AAT conformer to be very close to that of SSC conformer. This may be due to the influence of water media.
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Ivanov, Evgeny, Elena Lebedeva, Arina Pakina und Nadezhda Ivanova. „Comparative description of the extraordinary phenomenon "thermally activated isobaric partial structure compaction" of water as a solute in some alkanols and alkylamines“. From Chemistry Towards Technology Step-By-Step 5, Nr. 1 (23.03.2024): 85–106. http://dx.doi.org/10.52957/2782-1900-2024-5-1-85-106.
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This review summarises the data available in the literature. It also includes the authors' published results of precision densimetric measurements. The research concerns with the physically unusual phenomenon of "thermally activated isobaric partial densification of the structure" (TIPCS) of dissolved water, or its so-called "negative partial molar expandability" (NPEA) in several organic solvents. They contain amphiproton hydroxyl-containing media of three alcohols: methyl alcohol (MA), tertiary butyl alcohol (TBAlcohol), and amyl or pentyl alcohol (TPA), so asprotophilic media of two amines: tert butylamine (TBAmine) and ethylenediamine (EDA). The discussed TIPCS phenomenon, associated with a decrease in the standard (partial at infinite dilution) volume of solvated water with increasing temperature, was discovered about half a century ago in alkanol solutions of H2O and recently - in water-containing media of alkylamines. However, nowadays this extraordinary effect has not yet found its physically based interpretation. It allows ones to predict the possibility of TIPCS occurrence in the binary liquid-phase system specifically selected for the study. Our comprehensive data analysis allowed us to make several inferences regarding the main characteristics of a standard solution of H2O in an organic solvent. They cause extraordinary changes in the volume of the formed solvatocomplex of water under the influence of increasing temperature. Firstly, the energy parameters of the intermolecular interaction (relative affinity) water solvent noticeably dominate over those of the solvent-solvent interaction. Those differences become more evident with increasing temperature. Secondly, a higher rate of thermal expansion of the organic solvent structure in volume (inbulk) is found than influence of temperature on structural packing of the resulting mixed molecular aggregate or water solvates complex. Thirdly, the difference in the parameters of water-solvent and solvent-solvent interactions depends not only on the proton-donor/acceptor properties of the molecules contacting in solution, but also on the configuration of the structural packing of the solvating medium. It determines the nature of steric hindrances to the formation of H-bonds. Therefore, the absolute values of the mentioned parameters of relative affinity at 298.15 K increase in the series: MA << EDA ≈ TBAmine < TPAlcohol < TBAmine. It can indicate a relative strengthening of the specific interaction (mainly through the formation of hydrogen bonds) between the molecules of water and amphiprotonic or protophilic solvent in the above sequence. Indeed, difference in the solvent-solvent and water-solvent hydrogen bonding energies in the discussed liquid media of alkylamines (TBAmine and EDA) and tertiary isomeric alkanols (TBAlcohol and TPA) - with the most evident basicity - turned out to be noticeably larger than in the structural packing of water methanol solution. The ability of the components to specific interactions is quite comparable in those compounds.
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Ivanov, Evgeny, Elena Lebedeva, Arina Pakina und Nadezhda Ivanova. „Comparative description of the extraordinary phenomenon "thermally activated isobaric partial structure compaction" of water as a solute in some alkanols and alkylamines“. From Chemistry Towards Technology Step-By-Step 5, Nr. 1 (23.03.2024): 8–32. http://dx.doi.org/10.52957/2782-1900-2024-5-1-8-32.
Der volle Inhalt der QuelleAnnotation:
This review summarises the data available in the literature. It also includes the authors' published results of precision densimetric measurements. The research concerns with the physically unusual phenomenon of "thermally activated isobaric partial densification of the structure" (TIPCS) of dissolved water, or its so-called "negative partial molar expandability" (NPEA) in several organic solvents. They contain amphiproton hydroxyl-containing media of three alcohols: methyl alcohol (MA), tertiary butyl alcohol (TBAlcohol), and amyl or pentyl alcohol (TPA), so asprotophilic media of two amines: tert butylamine (TBAmine) and ethylenediamine (EDA). The discussed TIPCS phenomenon, associated with a decrease in the standard (partial at infinite dilution) volume of solvated water with increasing temperature, was discovered about half a century ago in alkanol solutions of H2O and recently - in water-containing media of alkylamines. However, nowadays this extraordinary effect has not yet found its physically based interpretation. It allows ones to predict the possibility of TIPCS occurrence in the binary liquid-phase system specifically selected for the study. Our comprehensive data analysis allowed us to make several inferences regarding the main characteristics of a standard solution of H2O in an organic solvent. They cause extraordinary changes in the volume of the formed solvatocomplex of water under the influence of increasing temperature. Firstly, the energy parameters of the intermolecular interaction (relative affinity) water solvent noticeably dominate over those of the solvent-solvent interaction. Those differences become more evident with increasing temperature. Secondly, a higher rate of thermal expansion of the organic solvent structure in volume (inbulk) is found than influence of temperature on structural packing of the resulting mixed molecular aggregate or water solvates complex. Thirdly, the difference in the parameters of water-solvent and solvent-solvent interactions depends not only on the proton-donor/acceptor properties of the molecules contacting in solution, but also on the configuration of the structural packing of the solvating medium. It determines the nature of steric hindrances to the formation of H-bonds. Therefore, the absolute values of the mentioned parameters of relative affinity at 298.15 K increase in the series: MA << EDA ≈ TBAmine < TPAlcohol < TBAmine. It can indicate a relative strengthening of the specific interaction (mainly through the formation of hydrogen bonds) between the molecules of water and amphiprotonic or protophilic solvent in the above sequence. Indeed, difference in the solvent-solvent and water-solvent hydrogen bonding energies in the discussed liquid media of alkylamines (TBAmine and EDA) and tertiary isomeric alkanols (TBAlcohol and TPA) - with the most evident basicity - turned out to be noticeably larger than in the structural packing of water methanol solution. The ability of the components to specific interactions is quite comparable in those compounds.
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Rochyani, Neny. „Comparison Analysis of Anthocyanin Substances in various Plants for Testing Media of Formalin and Borax Content in Food“. E3S Web of Conferences 68 (2018): 03005. http://dx.doi.org/10.1051/e3sconf/20186803005.
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Anthocyanin substances found in plants are known could be able to indicate acidic and alkaline compounds which means it can indicate the presence of additives in various materials. Food is an important factor in human life as a basic need to grow and survive. The presence of foods containing formaldehyde and borax can endanger human health, therefore there is a need an effort and ingredients to identify the presence or absence of these substances. This can be done by making test equipment that is able to indicate food containing non-food additives. This study focused on comparative analysis of anthocyanin content in some plants to be used as food testing materials containing formalin and borax using filter paper, as well as knowing the effect of solvent variations on mass extraction of anthocyanins and yields. Testing using solvents, namely ethanol with variations, the test equipment is produced through extraction of plants and solvents which are then soaked in filter paper and dried so that they are absorbed therein. The test results show that the anthocyanin substance in all plant samples is good to be used as a test tool but the ipomea batatas L is better and the variation of solvent has a significant influence on the extraction of anthocyanin and rendemen, while the test media extracted using ethanol solvent variations can detect the formaldehyde content and borax well.
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Bhakuni, Kavya, Niketa Yadav und Pannuru Venkatesu. „A novel amalgamation of deep eutectic solvents and crowders as biocompatible solvent media for enhanced structural and thermal stability of bovine serum albumin“. Physical Chemistry Chemical Physics 22, Nr. 42 (2020): 24410–22. http://dx.doi.org/10.1039/d0cp04397d.
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