Study On The Solubilities Of O-Chlorotoluene And2,4-Dichlorotoluene In Subcritical Water In Fused Silica Capillary Reactor

The phase behaviors of organic compounds in hot compressed water are the basic of chemical reaction. The solubilities of solute in super、 subcritical water are expecially important for industrial process such as organic reaction mechanism and exctraction. methods for measuring the solubilities of compounds in HCW can be divided into two types of methods:static and dynamic methods. But in the static solubility measurement technique, withdrawing the sample solution from the equilibration cell may cause a considerable pressure drop and significantly disturb the phase equilibrium process. In dynamic solubility measurement technique, possible loss of solute in the valve or restrictor is a major limitation. Otherwise, the reaction equipment will be corroded seriouly by chlorinated organic compounds. So the solubilities of chlorinated organic compounds are lack.Our group has developed a new high-temperature and-pressure optically transparent FSCR reactor instead of traditional stainless steel autoclave or tubular flow reactor, combined with a heating/cooling stage and a polarizaiton microscope to study the phase behavior and solubilities of chlorinated organic compounds (o-chlorotoluene and2,4-dichlorotoluene) in subcritical water.In order to make sure that the precision of heating/cooling stage, we calibrated the temperature of heating/cooling stage by the supercritical point of ethnol and melting point of sodium nitrate. In order to ensure that the novel solubility apparatus was viable, the solubility of benzene in water was measured at specific temperatures, and the results were compared with literature data. And also studied the homogeneity of the o-chlorotoluene and2,4-dichlorotoluene solution using high-temperature and pressure optically transparent FSCR reactor combined with in-situ Raman spectroscopy system, and inveastigated the homogeneity based on quantitative analysis.On the basic of these work, we determined the solubilities of o-chlorotoluene and2,4-dichlorotoluene in the temperature range of236.1-283.3℃and266.3-302.4℃using the FSCR combined with a microscope recorder system, The results showed that the solubility of o-chlorotoluene and2,4-dichlorotoluene increased linearly with increasing temperature. This experimental method does not require sampling and subsequent analysis, has low energy and materials consumptions, and is safe and environmental friendly. It has great potential for being widely applied in solubility determinations of HOCs in sub-and supercritical fluids.