The equation of Patwardhan and Kumar for water activities of mixed electrolyte solutions is extended to aqueous solutions containing non-electrolytes. This equation and the linear isopiestic relation are used to predi...The equation of Patwardhan and Kumar for water activities of mixed electrolyte solutions is extended to aqueous solutions containing non-electrolytes. This equation and the linear isopiestic relation are used to predict water activities of 56 ternary aqueous solutions in terms of the data of their binary subsystems. Both equation of Patwardhan and Kumar and the linear isopiestic relation can provide good predictions for water activities of the present 40 electrolyte solutions, and the linear isopiestic relation generally yields better predictions. The predictions of the extended equation of Patwardhan and Kumar and the linear isopiestic relation are in general quite reasonable for the present 8 ternary solutions of electrolytes and non-electrolytes, and the results of the linear isopiestic relation are usually better. The predictions of these two methods generally agree well with the experimental data for the 8 non-electrolyte mixtures being studied, and the linear isopiestic relation is better.展开更多
Catechinone hair dyestuff was produced chemically from (+)-catechin by the oxidation with O2 in basic water/alcohol mixed solution. The effects of reaction conditions such as basicity, sorts of added base, temperature...Catechinone hair dyestuff was produced chemically from (+)-catechin by the oxidation with O2 in basic water/alcohol mixed solution. The effects of reaction conditions such as basicity, sorts of added base, temperature, alcohol molar fraction of solvent and sorts of added alcohols on the catechinone formation were studied in order to increase the efficiency of the dyestuff production. The amount of obtained catechinone increases with increasing basicity of the reaction solution. The dyestuff is obtained by adding monoethanol amine, diethanol amine, triethanol amine, l-arginine, Na2CO3, K2CO3, Na3PO4 or NaOH into the solution as a base and the most preferable base is monoethanol amine. The optimum temperature for the production in water/ethanol solution is 30°C. It was found that water-soluble alcohols such as methanol, ethanol, 2-propanol, 1-propanol and tert-butyl alcohol are available for preparing the dyestuff. The optimum alcohol molar fraction of the mixed solvent used for the dye formation is 0.45 for methanol, 0.25 for ethanol and 0.20 for 2-propanol, 0.15 for 1-propanol and 0.10 for tert-butyl alcohol. The amount of the obtained dyestuff reaches a maximum at 1) 0.35 and 0.59, 2) 0.35 or 3) 0.35 mol·kg¨1 of the concentration of (+)-catechin for the 1) water/methanol, 2) water/ethanol or 3) water/1-propanol system, respectively.展开更多
The mechanism for the production of acetic acid from ethanol and water mixture catalyzed by iridium catalyst has been theoretically investigated.The cooperation of the iridium center and bpyO ligand is highlighted,whi...The mechanism for the production of acetic acid from ethanol and water mixture catalyzed by iridium catalyst has been theoretically investigated.The cooperation of the iridium center and bpyO ligand is highlighted,which plays an important role in the catalytic activity.The hydrogen release from the iridium center is the rate-determining step,with an energy barrier of 22.5 kcal/mol.The electronic structure analysis suggests electron-donating substituents could decrease the energy barrier.展开更多
基金the National Natural Science Foundation of China (No. 20276037, No. 20006010).
文摘The equation of Patwardhan and Kumar for water activities of mixed electrolyte solutions is extended to aqueous solutions containing non-electrolytes. This equation and the linear isopiestic relation are used to predict water activities of 56 ternary aqueous solutions in terms of the data of their binary subsystems. Both equation of Patwardhan and Kumar and the linear isopiestic relation can provide good predictions for water activities of the present 40 electrolyte solutions, and the linear isopiestic relation generally yields better predictions. The predictions of the extended equation of Patwardhan and Kumar and the linear isopiestic relation are in general quite reasonable for the present 8 ternary solutions of electrolytes and non-electrolytes, and the results of the linear isopiestic relation are usually better. The predictions of these two methods generally agree well with the experimental data for the 8 non-electrolyte mixtures being studied, and the linear isopiestic relation is better.
文摘Catechinone hair dyestuff was produced chemically from (+)-catechin by the oxidation with O2 in basic water/alcohol mixed solution. The effects of reaction conditions such as basicity, sorts of added base, temperature, alcohol molar fraction of solvent and sorts of added alcohols on the catechinone formation were studied in order to increase the efficiency of the dyestuff production. The amount of obtained catechinone increases with increasing basicity of the reaction solution. The dyestuff is obtained by adding monoethanol amine, diethanol amine, triethanol amine, l-arginine, Na2CO3, K2CO3, Na3PO4 or NaOH into the solution as a base and the most preferable base is monoethanol amine. The optimum temperature for the production in water/ethanol solution is 30°C. It was found that water-soluble alcohols such as methanol, ethanol, 2-propanol, 1-propanol and tert-butyl alcohol are available for preparing the dyestuff. The optimum alcohol molar fraction of the mixed solvent used for the dye formation is 0.45 for methanol, 0.25 for ethanol and 0.20 for 2-propanol, 0.15 for 1-propanol and 0.10 for tert-butyl alcohol. The amount of the obtained dyestuff reaches a maximum at 1) 0.35 and 0.59, 2) 0.35 or 3) 0.35 mol·kg¨1 of the concentration of (+)-catechin for the 1) water/methanol, 2) water/ethanol or 3) water/1-propanol system, respectively.
基金This work is supported by the National Natural Science Foundation of China (No. 21672018)the Fundamental Research Funds for the Central Universities (No. XK1802-6). We thank the National Supercomputing Center in Tianjin (TianHe-1) for providing part of the computational sources.
文摘The mechanism for the production of acetic acid from ethanol and water mixture catalyzed by iridium catalyst has been theoretically investigated.The cooperation of the iridium center and bpyO ligand is highlighted,which plays an important role in the catalytic activity.The hydrogen release from the iridium center is the rate-determining step,with an energy barrier of 22.5 kcal/mol.The electronic structure analysis suggests electron-donating substituents could decrease the energy barrier.
