Molecular dynamics method was used to establish composite wall/inorganic nanopores of three pore sizes, three shale oil systems, five CO_(2)-cosolvent systems, and pure CO_(2) system. The process of CO_(2)-cosolvent d...Molecular dynamics method was used to establish composite wall/inorganic nanopores of three pore sizes, three shale oil systems, five CO_(2)-cosolvent systems, and pure CO_(2) system. The process of CO_(2)-cosolvent displacement of crude oil in shale nanopores and carbon storage was simulated and the influencing factors of displacement and storage were analyzed. It is shown that the attraction of the quartz wall to shale oil increases with the degree of hydroxylation. The higher the degree of quartz hydroxylation, the more difficult it is to extract the polar components of shale oil. Nanopore size also has a great impact on shale oil displacement efficiency. The larger the pore size, the higher the shale oil displacement efficiency. The closer the cosolvent molecules are to the polarity of the shale oil, the higher the mutual solubility of CO_(2) and shale oil. The more the non-polar components of shale oil, the lower the mutual solubility of CO_(2) and shale oil with highly polar cosolvent. Ethyl acetate is more effective in stripping relatively high polar shale oil, while dimethyl ether is more effective in stripping relatively low polar shale oil. Kerogen is highly adsorptive, especially to CO_(2). The CO_(2) inside the kerogen is not easy to diffuse and leak, thus allowing for a stable carbon storage. The highest CO_(2) storage rate is observed when dimethyl ether is used as a cosolvent, and the best storage stability is observed when ethyl acetate is used as a cosolvent.展开更多
The poor aqueous solubility of drugs is a challenging problem faced by pharmaceutical scientists in drug formulation. Cosolvency and micellization techniques have been severally used to enhance the solubility of poorl...The poor aqueous solubility of drugs is a challenging problem faced by pharmaceutical scientists in drug formulation. Cosolvency and micellization techniques have been severally used to enhance the solubility of poorly aqueous soluble drugs. Mirtazapine, a tetracyclic antidepressant used for the treatment of moderate to severe depression and anxiety, has very poor aqueous solubility. The objective of the study was to investigate the effect of solubilizing agents (cosolvents and surfactants) on the aqueous solubility of mirtazapine while envisaging that any significant improvement in its aqueous solubility could contribute towards alleviating the withdrawal symptoms often associated with the drug. The solubility of mirtazapine was determined at room temperature in aqueous mixtures of cosolvents (propylene glycol and polyethylene glycol 400) and surfactants (polysorbate 20, polysorbate 80 and sodium lauryl sulfate). An exponential increase in mirtazapine solubility was observed when total drug solubility in water-cosolvent system was plotted against cosolvent fraction volume. Polyethylene glycol 400 gave larger solubilization capacity (σ) when compared to propylene glycol. With the surfactants, linear relationship between the total solubility of the drug in water-surfactant mixtures and surfactant concentration was noted. Sodium lauryl sulfate showed the largest solubilization power (k) when compared to the nonionic surfactants (polysorbate 20 and polysorbate 80 respectively). A linear relationship between standard free energy and partition coefficient was also observed. The result of the study shows that aqueous solubility of mirtazapine is significantly improved by cosolvency and micellization and therefore there exists the possibility of improving the withdrawal symptoms often experienced with the drug. It also suggests that large free energy is required for drugs with high partition coefficients to permeate the biological membrane.展开更多
The solubility and sorption of oil by uncontaminated clay loam and silt loam soils were studied from water and cosolvent/water solutions using batch techniques. The data obtained from the dissolution and sorption expe...The solubility and sorption of oil by uncontaminated clay loam and silt loam soils were studied from water and cosolvent/water solutions using batch techniques. The data obtained from the dissolution and sorption experiments were used to evaluate the applicability of the cosolvent theory to oil as a complex mixture. Aqueous solubility and soil-water distribution coeffcients (Kd,w, L/kg) were estimated by extrapolating from cosolvent data, with a log-linear cosolvency model, to the volume fraction of cosolvent (fc) 0, and were compared with direct aqueous measurements. The extrapolated water solubility was 3.16 mg/L, in good agreement with the directly measured value of 3.83 mg/L. Extrapolated values of Kd,w for the two soils were close to each other but consistently higher than the values from direct aqueous measurements, because of the presence of dissolved organic carbon (DOC). The partition coe?cient (KDOC) between the DOC and the freely dissolved phase and the OC-normalized sorption coeffcient (KOC) were determined. The average values of logKDOC and logKOC were estimated as 4.34 and 3.32, respectively, giving insight into the possibility of oil becoming mobilized and/or of the soil being remedied. This study revealed that the cosolvency model can be applied to a broader range of hydrophobic organic chemicals (HOCs) than has been previously thought. The results aided in a reliable determination of water solubility and sorption coeffcients and provide information about the fate of oil in solvent-contaminated environment.展开更多
The effects of adding cosolvents of diglyme and 15 crown 5 to the reaction mixture of Wurtz type coupling of dichlorosilanes on the yield and relative molecular mass dispersity of polymethylphenethylsilane(PMPES) were...The effects of adding cosolvents of diglyme and 15 crown 5 to the reaction mixture of Wurtz type coupling of dichlorosilanes on the yield and relative molecular mass dispersity of polymethylphenethylsilane(PMPES) were discussed. The results show that addition of 10% (volume ratio of diglyme to toluene) diglyme as a cosolvent to the reaction mixture leads to the yield increase of PMPES with a monomodal distribution of relative molecular masses. Adding 10% diglyme to the reaction mixtures, the yields of polymethylcyclohexylsilane(PMCS) and copolymers (polymethylphenethylsilane co methylcyclohexylsilane), (the molar ratios of methylphenethyldichlorosilane to methylcyclohexyldichlorosilane were 2.0, 1.0 and 0.5, and the copolymers were abbreviated by Copolymers Ⅰ, Ⅱ, Ⅲ, respectively) are 47%, 52%, 54%, 53%, respectively. Their relative molecular masses ( w ) almost reach 10 5. These polysilanes were characterized by 1H NMR, IR and UV absorption spectrum.展开更多
Methyl linolenate was separated from its analogues by a new extraction system constructed by solvent,imidazolium based ionic liquids and cuprous salt. Firstly, the effect of ionic liquid on the dissolution of CuCl in ...Methyl linolenate was separated from its analogues by a new extraction system constructed by solvent,imidazolium based ionic liquids and cuprous salt. Firstly, the effect of ionic liquid on the dissolution of CuCl in acetonitrile, N,N-dimethylformamide(DMF), methanol and water was evaluated by visual observation.[C4Mim][Cl]can improve the dissolution of CuCl in acetonitrile. Then, for the new system as acetonitrile-ILs-CuCl, extraction equilibrium, distribution ratio and selectivity of methyl linolenate and its analogues were determined by gas chromatography analysis and the mass balance. The extraction time, IL structures and CuCl concentrations were investigated. Distribution ratio decreased slightly, but selectivity increased significantly with the addition of CuCl,[C4Mim][Cl] or [C4Vim][NTF2] into acetonitrile.[C4Vim][NTF2] had higher selectivity than [C4Mim][Cl].But the selectivity of the system combining CuCl with [C4Vim][NTF2] was much lower than with [C4 Mim][Cl].For the CuCl-[C4Mim][Cl]-acetonitrile, the extraction efficiency was better than CuCl-acetonitrile, increasing Cu^+ concentration effectively improved the separation selectivity when ratio of CuCl/[C4Mim][Cl] was less than 1. Compared with previous aqueous AgNO3 extractions, the method of using CuCl is a much cheaper and practical way to enrich unsaturated fatty acid.展开更多
The effect of cosolvent on the palladium catalyst which catalyze alkoxycarbonylation of allyl bromide in supercritical CO2 has been investigated. It was found that a small amount of cosolvent such as ethanol, CH2Cl2 a...The effect of cosolvent on the palladium catalyst which catalyze alkoxycarbonylation of allyl bromide in supercritical CO2 has been investigated. It was found that a small amount of cosolvent such as ethanol, CH2Cl2 and cyclohexane can affect both reaction yields and selectivities largely. Ethanol was the most favorable cosolvent for increasing the total yield of unsaturated esters and the selectivity of 3-butenoic acid ester. Using cosolvent ethanol and cocatalyst FeCl2 simultaneously can lead to better reaction results.展开更多
The solubility data of compounds in supercritical fluids and the correlation between the experimental solubility data and predicted solubility data are crucial to the development of supercritical technologies. In the ...The solubility data of compounds in supercritical fluids and the correlation between the experimental solubility data and predicted solubility data are crucial to the development of supercritical technologies. In the present work, the solubility data of silymarin(SM) in both pure supercritical carbon dioxide(SCCO2) and SCCO2 with added cosolvent was measured at temperatures ranging from 308 to 338 K and pressures from 8 to 22 MPa. The experimental data were fit with three semi-empirical density-based models(Chrastil, Bartle and Mendez-Santiago and Teja models) and a back-propagation artificial neural networks(BPANN) model. Interaction parameters for the models were obtained and the percentage of average absolute relative deviation(AARD%) in each calculation was determined. The correlation results were in good agreement with the experimental data. A comparison among the four models revealed that the experimental solubility data were more fit with the BPANN model with AARDs ranging from 1.14% to 2.15% for silymarin in pure SCCO2 and with added cosolvent. The results provide fundamental data for designing the extraction of SM or the preparation of its particle using SCCO2 techniques.展开更多
The morphology of active layer in bulk heterojunction(BHJ) organic solar cells is decisive to the device performance. Previous works have shown that the solvent engineering is an effective method to optimize the morph...The morphology of active layer in bulk heterojunction(BHJ) organic solar cells is decisive to the device performance. Previous works have shown that the solvent engineering is an effective method to optimize the morphology of active layer. However, screening the proper solvent is a tedious task, and we know very little about how to select a proper solvent for a particular system, especially for polymer/nonfullerene blend systems. Here, we combined the spectroscopic analysis in various solvent mixtures during film-forming process to reveal the relationship among the cosolvent characteristics, film-forming kinetics and film morphology. In this article, P3 HT/O-IDTBR blend was selected as model system due to being facile synthesized under a large-scale. Chlorobenzene(CB) was selected as main solvent, and the cosolvents were grouped into three categories according to its boiling point(bp) compared to CB.The cosolvents with lower bp, like chloroform(CF), can facilitate a faster film-forming process, reducing the domain size but sacrificing the crystallinity of both components. For the cosolvents with higher bp,like o-dichlorobenzene(DCB) and 1,2,4-trichlorobenzene(TCB), the self-organization process of P3 HT and O-IDTBR is separated and its duration was extended, constructing highly crystalline nanointerpenetrating network. However, the cosolvents with very high bp, such as chlornaphthalene(CN),would residue in film and keep P3 HT and O-IDTBR self-organizing for longer time, leading to larger phase separation. This work systematically investigated the effect of cosolvent on the film-forming kinetics, and proposed a guideline of how to select a proper cosolvent according to the crystallinity and domain size of active layer.展开更多
The effect of cosolvent cyclohexane, chloroform, and acetonitrile on the keto-enol tautomeric equilibrium of ethyl acetoacetate in supercritical CO2 was studied by UV-Vis spectroscopy over the pressure range from 76 t...The effect of cosolvent cyclohexane, chloroform, and acetonitrile on the keto-enol tautomeric equilibrium of ethyl acetoacetate in supercritical CO2 was studied by UV-Vis spectroscopy over the pressure range from 76 to 110 bar at 308.15 K. It was found that the equilibrium constant decreases with increasing polarity of the cosolvents.展开更多
The keto-enol tautomerization of ethyl acetoacetate (EAA) in supercritical CO2-ethanol mixture has been investigated at 308.15 K and at different pressures using UV-Visspectroscopy. A method for calculating the local ...The keto-enol tautomerization of ethyl acetoacetate (EAA) in supercritical CO2-ethanol mixture has been investigated at 308.15 K and at different pressures using UV-Visspectroscopy. A method for calculating the local composition about EAA has been developed based on the relationship between the equilibrium constant and dielectric property of the mixing solvent. The results indicate that the local concentration of ethanol surrounding EAA is much higher than that in the bulk.展开更多
We report a carbon/carbon capacitor based on micro/mesoporous carbon electrodes with cost-effective and eco-friendly aqueous choline bis(trifluoromethylsulfonyl)imide(Ch TFSI)electrolyte with a cosolvent enabling low-...We report a carbon/carbon capacitor based on micro/mesoporous carbon electrodes with cost-effective and eco-friendly aqueous choline bis(trifluoromethylsulfonyl)imide(Ch TFSI)electrolyte with a cosolvent enabling low-temperature operation down to-30℃.For this purpose,a Mg O-templated hierarchical carbon(MP98B)with an average mesopore diameter of 3.5 nm was prepared by pyrolysis of magnesium citrate hydrate at 900℃.To reach lower temperatures,the melting point and viscosity of the aqueous electrolyte were reduced by mixing water(W)with an organic solvent(methanol,M,or isopropanol,I)of high dielectric constant and low viscosity.5 mol kg^(-1)(5 m)Ch TFSI in an optimized volume fraction of cosolvent,M_(0.75)W_(0.25),and I_(0.75)W_(0.25),showed the highest conductivity;the higher conductivity in M_(0.75)W_(0.25)(22.8 and 3.1 m S cm^(-1) at 20 and-30℃,respectively)than in I_(0.75)W_(0.25)(8.5 and0.5 m S cm^(-1)at 20 and-30℃,respectively)is attributed to the lower viscosity of the M_(0.75)W_(0.25)solution.The electrochemical stability window(ESW)of 5 m Ch TFSI in M_(0.75)W_(0.25)and I_(0.75)W_(0.25)(1.6 V)on an MP98B electrode was determined by applying the S-method.Meanwhile,by adjusting the mass ratio of the two electrodes,a MP98B/MP98B capacitor using the 5 m electrolyte in M_(0.75)W_(0.25)could operate with a good life span up to 1.6 V while exhibiting a better charge propagation,greater specific capacitance,and higher specific energy than in I_(0.75)W_(0.25).展开更多
The objective of the present study was to examine the influence of cosolvent system and micro-emulsion formulation on in-vitro skin permeation of gabapentin, furthermore, to characterize the physicochemical properties...The objective of the present study was to examine the influence of cosolvent system and micro-emulsion formulation on in-vitro skin permeation of gabapentin, furthermore, to characterize the physicochemical properties of drug-loaded oil-in-water (o/w) and water-in-oil (w/o) cremophor 40-based microemulsions in comparison to the blank counterparts. The cosolvent system prepared by homogenous mixing is composed of ethanol-water and propylene glycol-water mixture (90:10, 80:20, 70:30 v/v) respectively. The microemulsion consisted of coconut oil, water and mixture of cremophor 40 (surfactant) and ethanol (cosurfactant) and was prepared by aqueous phase titration method. Physicochemical properties of microemulsions were determined using reported procedures. Transdermal flux for gabapentin was studied in-vitro using modified Franz diffusion cells. The physicochemical properties of drug-loaded microemulsions and their blank counterparts were generally alike, however, slight variation in pH and viscosity was observed probably due to the intrinsic properties of the drug. The ethanol-water system (70:30 v/v) gave higher flux for gabapentin when compared to propylene glycol-water system (70:30 v/v). The w/o microemulsion formulations resulted in, higher flux for gabapentin when compared to o/w formulations. FTIR spectra of the untreated stratum corneum, when compared to cosolvent system and microemulsion treated stratum corneum, suggest the mechanism of permeation to be disruption of lipid bilayers and keratin denaturation of the stratum corneum. The results show that incorporation of gabapentin into microemulsions did not change the microemulsion type. The in vitro permeation data obtained from experimental work suggest that the cosolvent system (ethanol-water 70:30 v/v) and w/o microemulsion formulations respectively, can be successfully used as potential vehicles in developing transdermal therapeutic systems for gabapentin.展开更多
A remarkable rate enhancement technique has been devised for a typical nucleophilic displacement reaction by using triphase catalytic materials based on tetraoctylammonium exchange forms of hectorite clay. Pseudo-firs...A remarkable rate enhancement technique has been devised for a typical nucleophilic displacement reaction by using triphase catalytic materials based on tetraoctylammonium exchange forms of hectorite clay. Pseudo-first order rate constants (kobs) for the conversion of 1-bromobutane to the corresponding chloride under triphase conditions using the clay catalyst in the presence of various polar cosolvents have been observed. The results here have shown that the addition of a cosolvent increases the catalytic activity of the triphase system by several fold. In addition, the results have demonstrated that each cosolvent has a unique concentration for achieving an optimum reaction rate.展开更多
Transdermal drug delivery not only has contributed immensely to medical practice, but has enjoyed enormous interest in the field of cosmetic and pharmaceutical industries. Nevirapine, a non‐nucleoside reverse transcr...Transdermal drug delivery not only has contributed immensely to medical practice, but has enjoyed enormous interest in the field of cosmetic and pharmaceutical industries. Nevirapine, a non‐nucleoside reverse transcriptase inhibitor (NNRTI) is used clinically for the treatment of HIV‐ 1 infection. The aim of the present study is to investigate the influence of cosolvents (glycerol, propylene glycol, ethanol, polyethylene glycol 400) and surfactants (polysorbate 20, polysorbate 80, sodium lauryl sulfate, sodium cholate and cetrimide) on the dermal permeability coefficient of nevirapine by utilizing established and recognized mathematical model that employs partition coefficient as one of its molecular descriptors. The partition coefficient of nevirapine is determined in chloroform-water system at room temperature using the shake flask method. The results show that all the cosolvents used in this study decrease the partition coefficient of nevirapine. The same decrease in the partition coefficient of nevirapine is observed with all the surfactants investigated. The order of dermal enhancement potential of the vehicles studied based on the predicted permeability coefficient is glycerol > propylene glycol > ethanol > polyethylene glycol 400 for the cosolvents while tween 20 > tween 80 > sodium lauryl sulfate > sodium cholate > cetrimide for the surfactants. The maximum predicted flux through skin was obtained by multiplying the predicted permeability coefficient and the drug aqueous solubility. As the rate of penetration into the skin is quantitatively assessed by the use of permeability coefficient, the findings suggest that for dermal formulation of nevirapine, glycerol and tween 20 are the most preferred vehicles out of the vehicles investigated. Furthermore, the results of the correlation coefficients obtained by plotting permeability coefficient or maximum predicted flux, versus logarithm partition coefficient indicate that permeability coefficient can be a more reliable parameter to predict transdermal absorption of nevirapine than flux.展开更多
Two-dimensional(2D)nanomaterials have aroused immense attention in extensive applications due to their intriguing physical and chemical properties.However,there is a formidable challenge to prepare few-layered and fun...Two-dimensional(2D)nanomaterials have aroused immense attention in extensive applications due to their intriguing physical and chemical properties.However,there is a formidable challenge to prepare few-layered and functionalized 2D nanomaterials in an effective and universal way.Herein,we developed an integrated strategy of glucose-assisted mechanochemical exfoliation and cosolvent-intensified sonication exfoliation to effectively exfoliate and functionalize 2D materials.Taking exfoliation of boron nitride(BN)as an example,the production yield and functionalization ratio of BN nanosheets(BNNSs)reached 47.5%and 25.8 wt.%,188%and 16%higher than that of BNNSs without sonication exfoliation,respectively.The introduction of glucose not only augmented the friction force between adjacent BN layers to promote the efficiency of ball-milling-driven exfoliation supported by density functional theory calculation,but also reacted with active edges of BNNSs for functionalization.Afterwards,cosolventintensified sonication exfoliation strongly stabilized exfoliated BNNSs,obviously boosting the exfoliation yield.This proposed method is universal for preparing various 2D nanomaterials like molybdenum disulfide,tungsten disulfide,and graphene nanosheets.The thin plate structure and high functionalization ratio enabled the release of property superiorities of 2D nanomaterials.Our work offers a promising prototype to realize mass production of functionalized 2D nanomaterials.展开更多
A set of optimal conditions for supercritical fluid extraction(SFE)of daidzein in soybean previously subjected to extrusion at the rotate speed of screw 4.5×g and the temperature of 80℃was developed.The quadrati...A set of optimal conditions for supercritical fluid extraction(SFE)of daidzein in soybean previously subjected to extrusion at the rotate speed of screw 4.5×g and the temperature of 80℃was developed.The quadratic orthogonal rotation design with five factors(extracting temperature,extracting time,ethanlol content,cosolvent quantity and flow rate)was used and a mathematical model was developed based the experimental results.Optimal conditions were verified and compared with control experiments conducted in parallel.The results from SFE showed that all five experiment factors had significant effects on the yield of daidzein.The mathematical model agreed well with the experimental results.It was found that there were 27 optimal extract conditions under which daidzein yield was higher than 0.092%.The optimal extracting conditions were stable and reproducible.Results from the control experiments showed that extrusion could significantly enhance the extraction of daidzein.The extraction of daidzein from extruded soybean and its products with supercritical CO_(2) is a potential technique for practical applications in the future.展开更多
基金Supported by National Natural Science Foundation of China(52304021,52204031)Natural Science Foundation of Sichuan Province(2022NSFSC0205)National Science and Technology Major Project of China(2017ZX05049006-010).
文摘Molecular dynamics method was used to establish composite wall/inorganic nanopores of three pore sizes, three shale oil systems, five CO_(2)-cosolvent systems, and pure CO_(2) system. The process of CO_(2)-cosolvent displacement of crude oil in shale nanopores and carbon storage was simulated and the influencing factors of displacement and storage were analyzed. It is shown that the attraction of the quartz wall to shale oil increases with the degree of hydroxylation. The higher the degree of quartz hydroxylation, the more difficult it is to extract the polar components of shale oil. Nanopore size also has a great impact on shale oil displacement efficiency. The larger the pore size, the higher the shale oil displacement efficiency. The closer the cosolvent molecules are to the polarity of the shale oil, the higher the mutual solubility of CO_(2) and shale oil. The more the non-polar components of shale oil, the lower the mutual solubility of CO_(2) and shale oil with highly polar cosolvent. Ethyl acetate is more effective in stripping relatively high polar shale oil, while dimethyl ether is more effective in stripping relatively low polar shale oil. Kerogen is highly adsorptive, especially to CO_(2). The CO_(2) inside the kerogen is not easy to diffuse and leak, thus allowing for a stable carbon storage. The highest CO_(2) storage rate is observed when dimethyl ether is used as a cosolvent, and the best storage stability is observed when ethyl acetate is used as a cosolvent.
文摘The poor aqueous solubility of drugs is a challenging problem faced by pharmaceutical scientists in drug formulation. Cosolvency and micellization techniques have been severally used to enhance the solubility of poorly aqueous soluble drugs. Mirtazapine, a tetracyclic antidepressant used for the treatment of moderate to severe depression and anxiety, has very poor aqueous solubility. The objective of the study was to investigate the effect of solubilizing agents (cosolvents and surfactants) on the aqueous solubility of mirtazapine while envisaging that any significant improvement in its aqueous solubility could contribute towards alleviating the withdrawal symptoms often associated with the drug. The solubility of mirtazapine was determined at room temperature in aqueous mixtures of cosolvents (propylene glycol and polyethylene glycol 400) and surfactants (polysorbate 20, polysorbate 80 and sodium lauryl sulfate). An exponential increase in mirtazapine solubility was observed when total drug solubility in water-cosolvent system was plotted against cosolvent fraction volume. Polyethylene glycol 400 gave larger solubilization capacity (σ) when compared to propylene glycol. With the surfactants, linear relationship between the total solubility of the drug in water-surfactant mixtures and surfactant concentration was noted. Sodium lauryl sulfate showed the largest solubilization power (k) when compared to the nonionic surfactants (polysorbate 20 and polysorbate 80 respectively). A linear relationship between standard free energy and partition coefficient was also observed. The result of the study shows that aqueous solubility of mirtazapine is significantly improved by cosolvency and micellization and therefore there exists the possibility of improving the withdrawal symptoms often experienced with the drug. It also suggests that large free energy is required for drugs with high partition coefficients to permeate the biological membrane.
基金the National Basic Research Program of China (No. 2004CB418504)
文摘The solubility and sorption of oil by uncontaminated clay loam and silt loam soils were studied from water and cosolvent/water solutions using batch techniques. The data obtained from the dissolution and sorption experiments were used to evaluate the applicability of the cosolvent theory to oil as a complex mixture. Aqueous solubility and soil-water distribution coeffcients (Kd,w, L/kg) were estimated by extrapolating from cosolvent data, with a log-linear cosolvency model, to the volume fraction of cosolvent (fc) 0, and were compared with direct aqueous measurements. The extrapolated water solubility was 3.16 mg/L, in good agreement with the directly measured value of 3.83 mg/L. Extrapolated values of Kd,w for the two soils were close to each other but consistently higher than the values from direct aqueous measurements, because of the presence of dissolved organic carbon (DOC). The partition coe?cient (KDOC) between the DOC and the freely dissolved phase and the OC-normalized sorption coeffcient (KOC) were determined. The average values of logKDOC and logKOC were estimated as 4.34 and 3.32, respectively, giving insight into the possibility of oil becoming mobilized and/or of the soil being remedied. This study revealed that the cosolvency model can be applied to a broader range of hydrophobic organic chemicals (HOCs) than has been previously thought. The results aided in a reliable determination of water solubility and sorption coeffcients and provide information about the fate of oil in solvent-contaminated environment.
基金The National Natural Science Foundation of China !(No .2 8970 817)
文摘The effects of adding cosolvents of diglyme and 15 crown 5 to the reaction mixture of Wurtz type coupling of dichlorosilanes on the yield and relative molecular mass dispersity of polymethylphenethylsilane(PMPES) were discussed. The results show that addition of 10% (volume ratio of diglyme to toluene) diglyme as a cosolvent to the reaction mixture leads to the yield increase of PMPES with a monomodal distribution of relative molecular masses. Adding 10% diglyme to the reaction mixtures, the yields of polymethylcyclohexylsilane(PMCS) and copolymers (polymethylphenethylsilane co methylcyclohexylsilane), (the molar ratios of methylphenethyldichlorosilane to methylcyclohexyldichlorosilane were 2.0, 1.0 and 0.5, and the copolymers were abbreviated by Copolymers Ⅰ, Ⅱ, Ⅲ, respectively) are 47%, 52%, 54%, 53%, respectively. Their relative molecular masses ( w ) almost reach 10 5. These polysilanes were characterized by 1H NMR, IR and UV absorption spectrum.
文摘Methyl linolenate was separated from its analogues by a new extraction system constructed by solvent,imidazolium based ionic liquids and cuprous salt. Firstly, the effect of ionic liquid on the dissolution of CuCl in acetonitrile, N,N-dimethylformamide(DMF), methanol and water was evaluated by visual observation.[C4Mim][Cl]can improve the dissolution of CuCl in acetonitrile. Then, for the new system as acetonitrile-ILs-CuCl, extraction equilibrium, distribution ratio and selectivity of methyl linolenate and its analogues were determined by gas chromatography analysis and the mass balance. The extraction time, IL structures and CuCl concentrations were investigated. Distribution ratio decreased slightly, but selectivity increased significantly with the addition of CuCl,[C4Mim][Cl] or [C4Vim][NTF2] into acetonitrile.[C4Vim][NTF2] had higher selectivity than [C4Mim][Cl].But the selectivity of the system combining CuCl with [C4Vim][NTF2] was much lower than with [C4 Mim][Cl].For the CuCl-[C4Mim][Cl]-acetonitrile, the extraction efficiency was better than CuCl-acetonitrile, increasing Cu^+ concentration effectively improved the separation selectivity when ratio of CuCl/[C4Mim][Cl] was less than 1. Compared with previous aqueous AgNO3 extractions, the method of using CuCl is a much cheaper and practical way to enrich unsaturated fatty acid.
文摘The effect of cosolvent on the palladium catalyst which catalyze alkoxycarbonylation of allyl bromide in supercritical CO2 has been investigated. It was found that a small amount of cosolvent such as ethanol, CH2Cl2 and cyclohexane can affect both reaction yields and selectivities largely. Ethanol was the most favorable cosolvent for increasing the total yield of unsaturated esters and the selectivity of 3-butenoic acid ester. Using cosolvent ethanol and cocatalyst FeCl2 simultaneously can lead to better reaction results.
基金supported financially by the Subject Chief Scientist Program (10XD14303900) from Science and Technology Commission of Shanghai Municipalitythe Special Research Fund for the Doctoral Program of Higher Education of China (20123107110005)
文摘The solubility data of compounds in supercritical fluids and the correlation between the experimental solubility data and predicted solubility data are crucial to the development of supercritical technologies. In the present work, the solubility data of silymarin(SM) in both pure supercritical carbon dioxide(SCCO2) and SCCO2 with added cosolvent was measured at temperatures ranging from 308 to 338 K and pressures from 8 to 22 MPa. The experimental data were fit with three semi-empirical density-based models(Chrastil, Bartle and Mendez-Santiago and Teja models) and a back-propagation artificial neural networks(BPANN) model. Interaction parameters for the models were obtained and the percentage of average absolute relative deviation(AARD%) in each calculation was determined. The correlation results were in good agreement with the experimental data. A comparison among the four models revealed that the experimental solubility data were more fit with the BPANN model with AARDs ranging from 1.14% to 2.15% for silymarin in pure SCCO2 and with added cosolvent. The results provide fundamental data for designing the extraction of SM or the preparation of its particle using SCCO2 techniques.
基金supported by the National Natural Science Foundation of China (51773203, 51903211)the Fundamental Research Funds for the Central Universities (D5000200273)。
文摘The morphology of active layer in bulk heterojunction(BHJ) organic solar cells is decisive to the device performance. Previous works have shown that the solvent engineering is an effective method to optimize the morphology of active layer. However, screening the proper solvent is a tedious task, and we know very little about how to select a proper solvent for a particular system, especially for polymer/nonfullerene blend systems. Here, we combined the spectroscopic analysis in various solvent mixtures during film-forming process to reveal the relationship among the cosolvent characteristics, film-forming kinetics and film morphology. In this article, P3 HT/O-IDTBR blend was selected as model system due to being facile synthesized under a large-scale. Chlorobenzene(CB) was selected as main solvent, and the cosolvents were grouped into three categories according to its boiling point(bp) compared to CB.The cosolvents with lower bp, like chloroform(CF), can facilitate a faster film-forming process, reducing the domain size but sacrificing the crystallinity of both components. For the cosolvents with higher bp,like o-dichlorobenzene(DCB) and 1,2,4-trichlorobenzene(TCB), the self-organization process of P3 HT and O-IDTBR is separated and its duration was extended, constructing highly crystalline nanointerpenetrating network. However, the cosolvents with very high bp, such as chlornaphthalene(CN),would residue in film and keep P3 HT and O-IDTBR self-organizing for longer time, leading to larger phase separation. This work systematically investigated the effect of cosolvent on the film-forming kinetics, and proposed a guideline of how to select a proper cosolvent according to the crystallinity and domain size of active layer.
基金This work was financially support by National Basic Research Project(G2000048010).
文摘The effect of cosolvent cyclohexane, chloroform, and acetonitrile on the keto-enol tautomeric equilibrium of ethyl acetoacetate in supercritical CO2 was studied by UV-Vis spectroscopy over the pressure range from 76 to 110 bar at 308.15 K. It was found that the equilibrium constant decreases with increasing polarity of the cosolvents.
文摘The keto-enol tautomerization of ethyl acetoacetate (EAA) in supercritical CO2-ethanol mixture has been investigated at 308.15 K and at different pressures using UV-Visspectroscopy. A method for calculating the local composition about EAA has been developed based on the relationship between the equilibrium constant and dielectric property of the mixing solvent. The results indicate that the local concentration of ethanol surrounding EAA is much higher than that in the bulk.
基金financially supported by the National Science Centre(MAESTRO project UMO-2016/22/A/ST4/00092)。
文摘We report a carbon/carbon capacitor based on micro/mesoporous carbon electrodes with cost-effective and eco-friendly aqueous choline bis(trifluoromethylsulfonyl)imide(Ch TFSI)electrolyte with a cosolvent enabling low-temperature operation down to-30℃.For this purpose,a Mg O-templated hierarchical carbon(MP98B)with an average mesopore diameter of 3.5 nm was prepared by pyrolysis of magnesium citrate hydrate at 900℃.To reach lower temperatures,the melting point and viscosity of the aqueous electrolyte were reduced by mixing water(W)with an organic solvent(methanol,M,or isopropanol,I)of high dielectric constant and low viscosity.5 mol kg^(-1)(5 m)Ch TFSI in an optimized volume fraction of cosolvent,M_(0.75)W_(0.25),and I_(0.75)W_(0.25),showed the highest conductivity;the higher conductivity in M_(0.75)W_(0.25)(22.8 and 3.1 m S cm^(-1) at 20 and-30℃,respectively)than in I_(0.75)W_(0.25)(8.5 and0.5 m S cm^(-1)at 20 and-30℃,respectively)is attributed to the lower viscosity of the M_(0.75)W_(0.25)solution.The electrochemical stability window(ESW)of 5 m Ch TFSI in M_(0.75)W_(0.25)and I_(0.75)W_(0.25)(1.6 V)on an MP98B electrode was determined by applying the S-method.Meanwhile,by adjusting the mass ratio of the two electrodes,a MP98B/MP98B capacitor using the 5 m electrolyte in M_(0.75)W_(0.25)could operate with a good life span up to 1.6 V while exhibiting a better charge propagation,greater specific capacitance,and higher specific energy than in I_(0.75)W_(0.25).
文摘The objective of the present study was to examine the influence of cosolvent system and micro-emulsion formulation on in-vitro skin permeation of gabapentin, furthermore, to characterize the physicochemical properties of drug-loaded oil-in-water (o/w) and water-in-oil (w/o) cremophor 40-based microemulsions in comparison to the blank counterparts. The cosolvent system prepared by homogenous mixing is composed of ethanol-water and propylene glycol-water mixture (90:10, 80:20, 70:30 v/v) respectively. The microemulsion consisted of coconut oil, water and mixture of cremophor 40 (surfactant) and ethanol (cosurfactant) and was prepared by aqueous phase titration method. Physicochemical properties of microemulsions were determined using reported procedures. Transdermal flux for gabapentin was studied in-vitro using modified Franz diffusion cells. The physicochemical properties of drug-loaded microemulsions and their blank counterparts were generally alike, however, slight variation in pH and viscosity was observed probably due to the intrinsic properties of the drug. The ethanol-water system (70:30 v/v) gave higher flux for gabapentin when compared to propylene glycol-water system (70:30 v/v). The w/o microemulsion formulations resulted in, higher flux for gabapentin when compared to o/w formulations. FTIR spectra of the untreated stratum corneum, when compared to cosolvent system and microemulsion treated stratum corneum, suggest the mechanism of permeation to be disruption of lipid bilayers and keratin denaturation of the stratum corneum. The results show that incorporation of gabapentin into microemulsions did not change the microemulsion type. The in vitro permeation data obtained from experimental work suggest that the cosolvent system (ethanol-water 70:30 v/v) and w/o microemulsion formulations respectively, can be successfully used as potential vehicles in developing transdermal therapeutic systems for gabapentin.
文摘A remarkable rate enhancement technique has been devised for a typical nucleophilic displacement reaction by using triphase catalytic materials based on tetraoctylammonium exchange forms of hectorite clay. Pseudo-first order rate constants (kobs) for the conversion of 1-bromobutane to the corresponding chloride under triphase conditions using the clay catalyst in the presence of various polar cosolvents have been observed. The results here have shown that the addition of a cosolvent increases the catalytic activity of the triphase system by several fold. In addition, the results have demonstrated that each cosolvent has a unique concentration for achieving an optimum reaction rate.
文摘Transdermal drug delivery not only has contributed immensely to medical practice, but has enjoyed enormous interest in the field of cosmetic and pharmaceutical industries. Nevirapine, a non‐nucleoside reverse transcriptase inhibitor (NNRTI) is used clinically for the treatment of HIV‐ 1 infection. The aim of the present study is to investigate the influence of cosolvents (glycerol, propylene glycol, ethanol, polyethylene glycol 400) and surfactants (polysorbate 20, polysorbate 80, sodium lauryl sulfate, sodium cholate and cetrimide) on the dermal permeability coefficient of nevirapine by utilizing established and recognized mathematical model that employs partition coefficient as one of its molecular descriptors. The partition coefficient of nevirapine is determined in chloroform-water system at room temperature using the shake flask method. The results show that all the cosolvents used in this study decrease the partition coefficient of nevirapine. The same decrease in the partition coefficient of nevirapine is observed with all the surfactants investigated. The order of dermal enhancement potential of the vehicles studied based on the predicted permeability coefficient is glycerol > propylene glycol > ethanol > polyethylene glycol 400 for the cosolvents while tween 20 > tween 80 > sodium lauryl sulfate > sodium cholate > cetrimide for the surfactants. The maximum predicted flux through skin was obtained by multiplying the predicted permeability coefficient and the drug aqueous solubility. As the rate of penetration into the skin is quantitatively assessed by the use of permeability coefficient, the findings suggest that for dermal formulation of nevirapine, glycerol and tween 20 are the most preferred vehicles out of the vehicles investigated. Furthermore, the results of the correlation coefficients obtained by plotting permeability coefficient or maximum predicted flux, versus logarithm partition coefficient indicate that permeability coefficient can be a more reliable parameter to predict transdermal absorption of nevirapine than flux.
基金supported by the National Natural Science Foundation of China(Nos.52022061,52103099,51973138,and U21A2090).
文摘Two-dimensional(2D)nanomaterials have aroused immense attention in extensive applications due to their intriguing physical and chemical properties.However,there is a formidable challenge to prepare few-layered and functionalized 2D nanomaterials in an effective and universal way.Herein,we developed an integrated strategy of glucose-assisted mechanochemical exfoliation and cosolvent-intensified sonication exfoliation to effectively exfoliate and functionalize 2D materials.Taking exfoliation of boron nitride(BN)as an example,the production yield and functionalization ratio of BN nanosheets(BNNSs)reached 47.5%and 25.8 wt.%,188%and 16%higher than that of BNNSs without sonication exfoliation,respectively.The introduction of glucose not only augmented the friction force between adjacent BN layers to promote the efficiency of ball-milling-driven exfoliation supported by density functional theory calculation,but also reacted with active edges of BNNSs for functionalization.Afterwards,cosolventintensified sonication exfoliation strongly stabilized exfoliated BNNSs,obviously boosting the exfoliation yield.This proposed method is universal for preparing various 2D nanomaterials like molybdenum disulfide,tungsten disulfide,and graphene nanosheets.The thin plate structure and high functionalization ratio enabled the release of property superiorities of 2D nanomaterials.Our work offers a promising prototype to realize mass production of functionalized 2D nanomaterials.
文摘A set of optimal conditions for supercritical fluid extraction(SFE)of daidzein in soybean previously subjected to extrusion at the rotate speed of screw 4.5×g and the temperature of 80℃was developed.The quadratic orthogonal rotation design with five factors(extracting temperature,extracting time,ethanlol content,cosolvent quantity and flow rate)was used and a mathematical model was developed based the experimental results.Optimal conditions were verified and compared with control experiments conducted in parallel.The results from SFE showed that all five experiment factors had significant effects on the yield of daidzein.The mathematical model agreed well with the experimental results.It was found that there were 27 optimal extract conditions under which daidzein yield was higher than 0.092%.The optimal extracting conditions were stable and reproducible.Results from the control experiments showed that extrusion could significantly enhance the extraction of daidzein.The extraction of daidzein from extruded soybean and its products with supercritical CO_(2) is a potential technique for practical applications in the future.
