Solubility measurement experimental apparatus

Two experimental apparatuses were developed. The first setup described elsewhere [2], was used under static conditions to measure the solubility of the aTA in the supercritical fluid. 

The reliability and accuracy of the experimental apparatus and procedure were determined by the measurement of the solubility of carbon dioxide in pure water. The average value of the Ostwald coefficient, L0, obtained in this work was 0.8264 and agreed quite well with values in the literature (12). 

Figure 4, A schematic diagram of the experimental apparatus for solubility measurement 1 CO2 cylinder, 2 syringe pump, 3 pump controller, 4 thermostated water bath, 5 view cell, 6 magnetic stirrer, 7 liquid trap, 8 gas reservoir, 9 gas volume meter.

The following experimental techniques were used to measure the pressures and temperatures for solid-liquid-gas equilibrium, phase compositions (bubble and dew points) for gas-liquid equilibrium, and solid solubilities in supercritical pentane. Experimental procedures and the apparatus are described in detail elsewhere (13). 

In this paper, we describe the apparatus we use to make phase equilibrium measurements on mixtures of conqponents with greatly differing volatilities, putting particular emphasis on recent inqprove-ments over the previous version (6-7). We also describe quantitative measurements of the solubility of methyl oleate in supercritical fluids which can provide a basis for choosing a solvent to separate fatty acids in edible oils. In the following paper (JB.) we explore the utility of cubic equations of state to describe the results of supercritical fluid - liquid phase equilibrium measurements. Some additional experimental results on the mutual solubility of methyl linoleate and carbon dioxide are presented there also. 

The magnetically-stirred variable volume view cell apparatus, which was used to measure solubilities, is shown in Figure 2. The 2 in. o.d. x 5/8 in. i.d. 304 ss cell (28 mL usable volume) contained a 1 in. diameter by 3/8 in. thick sapphire window. A piston with two 90-durometer buna-N o-rings separated the experimental fluid from the pressurizing fluid, C02- Pressure was controlled by a 175 mL Lee Scientific model 501 computer controlled syringe pump. The view cell... 

Cukor and Prausnitz (16, 27) developed two apparatuses for rapid and accurate measurement of the solubility of gases in liquids at pressures in the vicinity of 1 atm over the temperature range 25-200 °C. Equilibrium compositions were determined from the total gas pressure and from a material balance. Their apparatuses with a careful operation, yielded solubilities of about 1 % accuracy. They reported values of solubility expressed in mole fraction (x2) of methane in n-hexadecane at 1 atm partial pressure and some experimental values of Henry s constant for methane, ethane and hydrogen in n-hexadecane, bicyclohexyl and diphenylme-thane for temperature range 25-200 C. 

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