A flow apparatus was set up for measuring the solubility of a solid solute in a supercritical fluid withthe presence of a small amount of entrainer.The solubilities of biphenyl,diphenylamine and benzoic acid insupercr...A flow apparatus was set up for measuring the solubility of a solid solute in a supercritical fluid withthe presence of a small amount of entrainer.The solubilities of biphenyl,diphenylamine and benzoic acid insupercritical carbon dioxide with one of the selected entrainers which were ethanol,acetone and n-hexanerespectively,were obtained in the pressure range of 10—32 MPa and the temperature range of 308—318K.Asolvolytic association theory has been proposed to explain the mechanism of entrainer effect,and theexperimental results were reasonably analysed.According to the solvolytic association theory,the association equa-tion of state was adopted to correlate the experimental data with good accuracy.展开更多
It is important to understand the mechanism and implications of different modifiers on analytical and preparative processes under chromatography with supercritical fluids (SFs) and under extraction with SFs. Supercrit...It is important to understand the mechanism and implications of different modifiers on analytical and preparative processes under chromatography with supercritical fluids (SFs) and under extraction with SFs. Supercritical fluid chromatography (SFC) and supercritical fluid extraction are generally carried out with neat supercritical carbon dioxide (SCCO2) or with SCCO2 containing modifiers (or cosolvents), especially for strongly polar compounds. For example, methanol is added as a cosolvent/modifier to SCCO2 for the extraction/separation of polar compounds. This paper discusses the influence of the modifier on the colligative properties of the principal mobile phase, which may define the situation in the total mobile phase in a chromatography column or in parts of a column under SFC. No colligative behavior of solutions reflects individual properties of the solutes. Their cross-interactions with solvents are discussed.展开更多
The conversion of biomass into hydrogen-rich gas provides a competitive means for producing clean energy and chemicals from renewable resources.Based on the principle of Gibbs free energy minimization, a new method wa...The conversion of biomass into hydrogen-rich gas provides a competitive means for producing clean energy and chemicals from renewable resources.Based on the principle of Gibbs free energy minimization, a new method was presented with better effectiveness and simplicity to be used for the prediction of chemical equilibrium composition of hydrogen production by biomass gasification in supercritical water(SCW).Applying this method to analyzing the process of glucose gasification in SCW, it was found that the product gas consisted primarily of hydrogen and carbon dioxide as well as a small amount of methane and carbon monoxide.The gas yield was strongly affected by reaction temperature and feedstock concentration and less affected by reaction pressure in the following range:temperature 623—1073 K,pressure 22.5—35 MPa,and concentration 0.1—0.8 mol·L -1 .The hydrogen production in product gas increased with the increase of temperature and decreased with the increase of concentration.展开更多
文摘A flow apparatus was set up for measuring the solubility of a solid solute in a supercritical fluid withthe presence of a small amount of entrainer.The solubilities of biphenyl,diphenylamine and benzoic acid insupercritical carbon dioxide with one of the selected entrainers which were ethanol,acetone and n-hexanerespectively,were obtained in the pressure range of 10—32 MPa and the temperature range of 308—318K.Asolvolytic association theory has been proposed to explain the mechanism of entrainer effect,and theexperimental results were reasonably analysed.According to the solvolytic association theory,the association equa-tion of state was adopted to correlate the experimental data with good accuracy.
文摘It is important to understand the mechanism and implications of different modifiers on analytical and preparative processes under chromatography with supercritical fluids (SFs) and under extraction with SFs. Supercritical fluid chromatography (SFC) and supercritical fluid extraction are generally carried out with neat supercritical carbon dioxide (SCCO2) or with SCCO2 containing modifiers (or cosolvents), especially for strongly polar compounds. For example, methanol is added as a cosolvent/modifier to SCCO2 for the extraction/separation of polar compounds. This paper discusses the influence of the modifier on the colligative properties of the principal mobile phase, which may define the situation in the total mobile phase in a chromatography column or in parts of a column under SFC. No colligative behavior of solutions reflects individual properties of the solutes. Their cross-interactions with solvents are discussed.
文摘The conversion of biomass into hydrogen-rich gas provides a competitive means for producing clean energy and chemicals from renewable resources.Based on the principle of Gibbs free energy minimization, a new method was presented with better effectiveness and simplicity to be used for the prediction of chemical equilibrium composition of hydrogen production by biomass gasification in supercritical water(SCW).Applying this method to analyzing the process of glucose gasification in SCW, it was found that the product gas consisted primarily of hydrogen and carbon dioxide as well as a small amount of methane and carbon monoxide.The gas yield was strongly affected by reaction temperature and feedstock concentration and less affected by reaction pressure in the following range:temperature 623—1073 K,pressure 22.5—35 MPa,and concentration 0.1—0.8 mol·L -1 .The hydrogen production in product gas increased with the increase of temperature and decreased with the increase of concentration.
