Study On The Solubilities Of Chlorobenzene And Copper Sulphate In Subcritical Water And Ethanol In Supcritical Carbon Dioxide

Sup/sub-critical fluids which had been widely used in chemical synthesis, extraction, environmental engineering and many other areas were regarded as one of the most promising and potential solvents. Currently, the supercritical water oxidation (SCWO) that emphasizes on the application of environmental protection had been most studied. It is an environmentally friendly and efficient new technology for hazard-free treatments of toxic and high concentration organic wastewater. However, in the actual application process it was encountered salt-plugging and corrosion which impede its industrial application seriously. As the basis of supercritical water oxidation reactors, the research of the solubilities of hydrophobic organics and inorganic salts in subcritical water had aroused great attention.Supercritical carbon dioxide (SC-CO₂) was regarded as one non-toxic, low critical temperature and low price solvent for chemical engineering application. The solubility of SC-CO₂ can be improved and the scope of its application will be widened by the addition of alcohol as a co-solvent. What's more it will become a hot topic in the research. Determination of ethanol solubility in SC-CO₂ was also very important for the extraction of substances in solution containing alcohol or using alcohol as a co-solvent.The solubilities of chlorobenzene and copper sulphate in SBCW and ethanol in SC-CO₂ were described in thesis, using a method which combined fused silica capillary with microscope by capturing the point of dissolution and precipitation. The results indicated that the solubility of chlorobenzene increased from 43.5 to 71.4 mg·g^-1 in water when temperature rose from 173.3 to 266.9 oC, and the temperature effect could be represented by a linear equation—S =0.3069T ^-10.188. The effects of pH and additives in copper sulfate solution on the metastability were also studied. And the solubility of copper sulphate increased from 10 to 180 mg·g^-1 in water when temperature rose from 114.2 to 157.1 oC. The pressure calculated by the Raoul's Law and saturated water vapor pressures is 160333 571368 Pa. The S-ρ-T curves of brine system derived from solubility data also fit the correlation with the Hydration Reaction Model.In addition a set of devices was established, with ethanol and carbon dioxide loaded into a silica capillary, the solubility of ethanol in SC-CO₂ was determinated. The experimental results indicated that the solubility of ethanol increased from 0.085 to 0.485 mg·mg^-1 in CO₂ when temperature rose from 77.6 to 183.8 oC, and the temperature effect could be represented by an exponential equation—S = 0.0231 e 0.016T.In summary, a new method using a silica capillary, in combination with a microscope and a video recorder system, has been applied to determine the solubility of chlorobenzene and copper sulphate in SBCW and ethanol in SC-CO₂. Moreover, it was demonstrated that the silica capillary method used here was low in energy and materials consumptions, safe, repeatable, and efficient. It has a great potential to be applied for the solubility determination of other organics and also inorganic salt crystals in sup/sub-critical fluids.