The thermal decomposition of 2, 2'-azobis (isobutyronitrile) (AIBN) in supercritical CO2 with cosolvent methanol or cyclohexane has been studied by using UV/Vis spectroscopic method at 335.15 K and at 12.0 MPa and...The thermal decomposition of 2, 2'-azobis (isobutyronitrile) (AIBN) in supercritical CO2 with cosolvent methanol or cyclohexane has been studied by using UV/Vis spectroscopic method at 335.15 K and at 12.0 MPa and 14.0 MPa. Both of the cosolvents can accelerate the decomposition rate, and the effect of methanol is more significant than that of the cyclohexane.展开更多
To overcome the aggregation of nanocrystals in a blend of inorganic material with conjugated polymers to prepare photovoltaic material, we used a co-solvent blend of CHCl3 with MeOH at a certain volume fraction to dis...To overcome the aggregation of nanocrystals in a blend of inorganic material with conjugated polymers to prepare photovoltaic material, we used a co-solvent blend of CHCl3 with MeOH at a certain volume fraction to disperse inorganic nanocrystals. The results show that when the volume fraction of MeOH is 50%, ZnO nanocrystals with an average diameter of 30 nm disperse well in the co-solvent solution. Its application in photovoltaic material was investigated in this work, and the photoluminescence（PL） spectra show that when ZnO was 50%（volume fraction） in solution and 25%（volume fraction） in film, the fluorescence quenching reached the maximum values 83.34% and 64.4%, respectively, indicating that electron could transfer from conjugated polymer to electron-acceptor ZnO effectively.展开更多
Supercritical Fluid Extraction (SFE) is emerging as a powerful technique in the extraction of metal ions. In the present study, the extraction of nitrates of uranium and thorium was carried out using supercritical car...Supercritical Fluid Extraction (SFE) is emerging as a powerful technique in the extraction of metal ions. In the present study, the extraction of nitrates of uranium and thorium was carried out using supercritical carbon dioxide (Sc-CO2) modified with various organophosphorous compounds such as dialkylalkyl phosphonates, trialkyl phosphates and trialkyl phosphine oxides in the presence of co-solvents such as methanol, dichlormethane and n-hexane. The influence of ligand and co-solvent on the extraction of the metal nitrates was studied in detail. These studies have established that co-solvent plays an important role in the extraction as well as fractionation of uranium and thorium nitrates. Polar co-solvent, methanol provided faster extraction without fractionation whereas the non-polar solvent, e.g. n-hexane provided some fractionation of metal nitrates though the extraction kinetics was slower.展开更多
Biofuels became more promising alternative to the fossil fuels because of the depletion of fossil resources, renewability, environmental benefits, and energy security. Ethanolysis of waste cooking oil with hexane as c...Biofuels became more promising alternative to the fossil fuels because of the depletion of fossil resources, renewability, environmental benefits, and energy security. Ethanolysis of waste cooking oil with hexane as co-solvent was carried out for the production of fatty acid ethyl ester (FAEE). This process reduced the severity of process parameters with high purity biodiesel yield. Process variables such as co-solvent ratio, ethanol to oil molar ratio, reaction temperature and reaction time were optimized. The maximum biodiesel yield of 88% was obtained at ethanol/oil molar ratio of 40:1, co-solvent (hexane) to oil ratio of 0.2% (v/v), reaction temperature of 300°C in 20 min of reaction time. Fatty acid ethyl ester (biodiesel) samples produced from this process were measured and evaluated using GC-MS analytical instrument. Thermo gravimetric analysis (TGA) was also performed to examine the thermal stability of waste cooking oil, ethyl esters and fuel blends. Fuel properties of ethyl esters were determined and compared with the ASTM standards for biodiesel, regular diesel and ethyl esters from different feedstock.展开更多
The two-step catalyzing process for biodiesel production from waste vegetable oil was assisted by both co-solvent and microwave irradiation. Central composite design (CCD) was employed to optimize the reaction conditi...The two-step catalyzing process for biodiesel production from waste vegetable oil was assisted by both co-solvent and microwave irradiation. Central composite design (CCD) was employed to optimize the reaction conditions. Optimal reaction conditions of the first step were alcohol to oil molar ratio of 9:1, catalyst (H2SO4) amount 1 wt%, reaction temperature 333 K, and reaction time 7.5 minutes;while for the second step, optimal reaction conditions were alcohol to oil molar ratio 12:1, catalyst (NaOH) amount 1 wt%, reaction temperature 333 K, and reaction time 2.0 minutes. The total reaction time was 9.5 min and the conversion rate of fatty acid methyl esters (FAMEs) achieved was 97.4%. The total reaction time was shorter than previous studies. Therefore, the co-solvent and microwave assisted two-step catalyzing process has a potential application in producing biodiesel from waste vegetable oil.展开更多
Effects of water-soluble co-solvents(WSCs)on the properties of water/oil Pickering emulsions were investigated. Pickering emulsions were prepared in the system of 1,2,4-trimethylbenzene(TMB)/ hydrophobic silica/water ...Effects of water-soluble co-solvents(WSCs)on the properties of water/oil Pickering emulsions were investigated. Pickering emulsions were prepared in the system of 1,2,4-trimethylbenzene(TMB)/ hydrophobic silica/water with varied concentrations of WSCs(ethanol, acetic acid and glycerin). Mean droplet diameter distributions of the obtained emulsions were studied to investigate the effects of WSCs types and concentrations. The results demonstrated that mean droplet diameter distributions decreased at first and then increased with the increase of WSC concentration. Moreover, the effect of WSC concentration on the phase inversion locus was further investigated. At the same time, infrared radiation(IR)spectrometer was used to investigate the mechanism. The results showed that the WSC attaching on hydrophobic silica changed the wettability of the particles, which facilitated the formation and phase inversion of the emulsion. The hydrogen bonds between the co-solvent groups attaching on the solid particles made a great effect on the droplet size of the emulsion and strengthened the interaction among emulsifiers. Overall, proper WSC was in favor of the stability of Pickering emulsion.展开更多
A series of water-based conductive carbon pastes were prepared by wet ball milling, followed by vacuum defoaming using isopropyl alcohol, propylene glycol or glycerin as co-solvents. Screen printing was then used to p...A series of water-based conductive carbon pastes were prepared by wet ball milling, followed by vacuum defoaming using isopropyl alcohol, propylene glycol or glycerin as co-solvents. Screen printing was then used to prepare conductive patterns. To determine the influence of co-solvent hydroxyl group number on the properties of water-based conductive carbon pastes, the rheological properties of the pastes and the surface morphologies and conductivities of the printed patterns were characterized. The results show that paste viscosity increased with the number of hydroxyl groups and the latter also affected thixotropy. In addition, the boiling points and surface tensions of the co-solvents increased consistently with hydroxyl group number, affecting the hydrodynamic flow. The conductive carbon paste created using propylene glycol as a co-solvent was the best for screen printing because of its weak coffee-ring effect and appro- priate rheological properties, resulting in a smooth coating surface and uniform deposition of the fillers. The resistivity of the pattern printed using paste PG, containing the closest packing of conductive carbon black particles, was 0.44 Ω cm.展开更多
Compared with organic electrolytes,aqueous electrolytes exhibit significantly higher ionic conductivity and possess inherent safety features,showcasing unique advantages in supercapacitors.However,challenges remain fo...Compared with organic electrolytes,aqueous electrolytes exhibit significantly higher ionic conductivity and possess inherent safety features,showcasing unique advantages in supercapacitors.However,challenges remain for low-salt aqueous electrolytes operating at high voltage and low temperature.Herein,we report a low-salt(0.87 m,m means mol kg^(-1))'salt in dimethyl sulfoxide/water'hybrid electrolyte with non-flammability via hybridizing aqueous electrolyte with an organic co-solvent of dimethyl sulfoxide(hydrogen bond acceptor).As a result,the 0.87 m hybrid electrolyte exhibits enhanced electrochemical stability,a freezing temperature below-50℃,and an outstanding ionic conductivity of 0.52mS cm~(-1)at-50℃.Dimethyl sulfoxide can anchor water molecules through intermolecular hydrogen bond interaction,effectively reinforcing the stability of water in the hybrid electrolyte.Furthermore,the interaction between dimethyl sulfoxide and water molecules diminishes the involvement of water in the generation of ordered ice crystals,finally facilitating the low-temperature performance of the hybrid electrolyte.When paired with the 0.87 m'salt in dimethyl sulfoxide/water'hybrid electrolyte,the symmetric supercapacitor presents a 2.0 V high operating voltage at 25℃,and can operate stably at-50℃.Importantly,the suppressed electrochemical reaction of water at-50℃further leads to the symmetric supercapacitor operated at a higher voltage of 2.6 V.This modification strategy opens an effective avenue to develop low-salt electrolytes for high-voltage and low-temperature aqueous supercapacitors.展开更多
利用叔丁醇作为共溶剂可使棕榈油、甲醇和催化剂形成均相体系,用于酯交换反应制备生物柴油,可以缩短反应时间。实验以棕榈油为原料,氢氧化钠为催化剂,在带夹套的玻璃反应器内进行反应。考察了共溶剂质量分数、催化剂质量分数、反应温度...利用叔丁醇作为共溶剂可使棕榈油、甲醇和催化剂形成均相体系,用于酯交换反应制备生物柴油,可以缩短反应时间。实验以棕榈油为原料,氢氧化钠为催化剂,在带夹套的玻璃反应器内进行反应。考察了共溶剂质量分数、催化剂质量分数、反应温度、醇油摩尔比等因素对生物柴油产率的影响,获得了最佳反应条件。实验结果表明,当叔丁醇质量为棕榈油质量的11.6%,催化剂质量为油质量的1.0%,反应温度为60℃,醇油摩尔比为6∶1时,反应2 m in后生物柴油产率达到了90%。展开更多
文摘The thermal decomposition of 2, 2'-azobis (isobutyronitrile) (AIBN) in supercritical CO2 with cosolvent methanol or cyclohexane has been studied by using UV/Vis spectroscopic method at 335.15 K and at 12.0 MPa and 14.0 MPa. Both of the cosolvents can accelerate the decomposition rate, and the effect of methanol is more significant than that of the cyclohexane.
基金Supported by the National Program on Key Basic Research Project of China(No.2010CB635111)the Doctorate Foundation of Northwestern Polytechnical University,China(No.CX201118)
文摘To overcome the aggregation of nanocrystals in a blend of inorganic material with conjugated polymers to prepare photovoltaic material, we used a co-solvent blend of CHCl3 with MeOH at a certain volume fraction to disperse inorganic nanocrystals. The results show that when the volume fraction of MeOH is 50%, ZnO nanocrystals with an average diameter of 30 nm disperse well in the co-solvent solution. Its application in photovoltaic material was investigated in this work, and the photoluminescence（PL） spectra show that when ZnO was 50%（volume fraction） in solution and 25%（volume fraction） in film, the fluorescence quenching reached the maximum values 83.34% and 64.4%, respectively, indicating that electron could transfer from conjugated polymer to electron-acceptor ZnO effectively.
文摘Supercritical Fluid Extraction (SFE) is emerging as a powerful technique in the extraction of metal ions. In the present study, the extraction of nitrates of uranium and thorium was carried out using supercritical carbon dioxide (Sc-CO2) modified with various organophosphorous compounds such as dialkylalkyl phosphonates, trialkyl phosphates and trialkyl phosphine oxides in the presence of co-solvents such as methanol, dichlormethane and n-hexane. The influence of ligand and co-solvent on the extraction of the metal nitrates was studied in detail. These studies have established that co-solvent plays an important role in the extraction as well as fractionation of uranium and thorium nitrates. Polar co-solvent, methanol provided faster extraction without fractionation whereas the non-polar solvent, e.g. n-hexane provided some fractionation of metal nitrates though the extraction kinetics was slower.
文摘Biofuels became more promising alternative to the fossil fuels because of the depletion of fossil resources, renewability, environmental benefits, and energy security. Ethanolysis of waste cooking oil with hexane as co-solvent was carried out for the production of fatty acid ethyl ester (FAEE). This process reduced the severity of process parameters with high purity biodiesel yield. Process variables such as co-solvent ratio, ethanol to oil molar ratio, reaction temperature and reaction time were optimized. The maximum biodiesel yield of 88% was obtained at ethanol/oil molar ratio of 40:1, co-solvent (hexane) to oil ratio of 0.2% (v/v), reaction temperature of 300°C in 20 min of reaction time. Fatty acid ethyl ester (biodiesel) samples produced from this process were measured and evaluated using GC-MS analytical instrument. Thermo gravimetric analysis (TGA) was also performed to examine the thermal stability of waste cooking oil, ethyl esters and fuel blends. Fuel properties of ethyl esters were determined and compared with the ASTM standards for biodiesel, regular diesel and ethyl esters from different feedstock.
文摘The two-step catalyzing process for biodiesel production from waste vegetable oil was assisted by both co-solvent and microwave irradiation. Central composite design (CCD) was employed to optimize the reaction conditions. Optimal reaction conditions of the first step were alcohol to oil molar ratio of 9:1, catalyst (H2SO4) amount 1 wt%, reaction temperature 333 K, and reaction time 7.5 minutes;while for the second step, optimal reaction conditions were alcohol to oil molar ratio 12:1, catalyst (NaOH) amount 1 wt%, reaction temperature 333 K, and reaction time 2.0 minutes. The total reaction time was 9.5 min and the conversion rate of fatty acid methyl esters (FAMEs) achieved was 97.4%. The total reaction time was shorter than previous studies. Therefore, the co-solvent and microwave assisted two-step catalyzing process has a potential application in producing biodiesel from waste vegetable oil.
基金Supported by the National Basic Research Program of China(“973”Program,No.2012CB720302)
文摘Effects of water-soluble co-solvents(WSCs)on the properties of water/oil Pickering emulsions were investigated. Pickering emulsions were prepared in the system of 1,2,4-trimethylbenzene(TMB)/ hydrophobic silica/water with varied concentrations of WSCs(ethanol, acetic acid and glycerin). Mean droplet diameter distributions of the obtained emulsions were studied to investigate the effects of WSCs types and concentrations. The results demonstrated that mean droplet diameter distributions decreased at first and then increased with the increase of WSC concentration. Moreover, the effect of WSC concentration on the phase inversion locus was further investigated. At the same time, infrared radiation(IR)spectrometer was used to investigate the mechanism. The results showed that the WSC attaching on hydrophobic silica changed the wettability of the particles, which facilitated the formation and phase inversion of the emulsion. The hydrogen bonds between the co-solvent groups attaching on the solid particles made a great effect on the droplet size of the emulsion and strengthened the interaction among emulsifiers. Overall, proper WSC was in favor of the stability of Pickering emulsion.
文摘A series of water-based conductive carbon pastes were prepared by wet ball milling, followed by vacuum defoaming using isopropyl alcohol, propylene glycol or glycerin as co-solvents. Screen printing was then used to prepare conductive patterns. To determine the influence of co-solvent hydroxyl group number on the properties of water-based conductive carbon pastes, the rheological properties of the pastes and the surface morphologies and conductivities of the printed patterns were characterized. The results show that paste viscosity increased with the number of hydroxyl groups and the latter also affected thixotropy. In addition, the boiling points and surface tensions of the co-solvents increased consistently with hydroxyl group number, affecting the hydrodynamic flow. The conductive carbon paste created using propylene glycol as a co-solvent was the best for screen printing because of its weak coffee-ring effect and appro- priate rheological properties, resulting in a smooth coating surface and uniform deposition of the fillers. The resistivity of the pattern printed using paste PG, containing the closest packing of conductive carbon black particles, was 0.44 Ω cm.
基金partly supported by the National Key R&D Program of China(2022YFB4101602)the National Natural Science Foundation of China(22078052)the Fundamental Research Funds for the Central Universities(DUT22ZD207)。
文摘Compared with organic electrolytes,aqueous electrolytes exhibit significantly higher ionic conductivity and possess inherent safety features,showcasing unique advantages in supercapacitors.However,challenges remain for low-salt aqueous electrolytes operating at high voltage and low temperature.Herein,we report a low-salt(0.87 m,m means mol kg^(-1))'salt in dimethyl sulfoxide/water'hybrid electrolyte with non-flammability via hybridizing aqueous electrolyte with an organic co-solvent of dimethyl sulfoxide(hydrogen bond acceptor).As a result,the 0.87 m hybrid electrolyte exhibits enhanced electrochemical stability,a freezing temperature below-50℃,and an outstanding ionic conductivity of 0.52mS cm~(-1)at-50℃.Dimethyl sulfoxide can anchor water molecules through intermolecular hydrogen bond interaction,effectively reinforcing the stability of water in the hybrid electrolyte.Furthermore,the interaction between dimethyl sulfoxide and water molecules diminishes the involvement of water in the generation of ordered ice crystals,finally facilitating the low-temperature performance of the hybrid electrolyte.When paired with the 0.87 m'salt in dimethyl sulfoxide/water'hybrid electrolyte,the symmetric supercapacitor presents a 2.0 V high operating voltage at 25℃,and can operate stably at-50℃.Importantly,the suppressed electrochemical reaction of water at-50℃further leads to the symmetric supercapacitor operated at a higher voltage of 2.6 V.This modification strategy opens an effective avenue to develop low-salt electrolytes for high-voltage and low-temperature aqueous supercapacitors.
文摘利用叔丁醇作为共溶剂可使棕榈油、甲醇和催化剂形成均相体系,用于酯交换反应制备生物柴油,可以缩短反应时间。实验以棕榈油为原料,氢氧化钠为催化剂,在带夹套的玻璃反应器内进行反应。考察了共溶剂质量分数、催化剂质量分数、反应温度、醇油摩尔比等因素对生物柴油产率的影响,获得了最佳反应条件。实验结果表明,当叔丁醇质量为棕榈油质量的11.6%,催化剂质量为油质量的1.0%,反应温度为60℃,醇油摩尔比为6∶1时,反应2 m in后生物柴油产率达到了90%。
