THE SOLUBILITY OF P-XYLENE IN WATER AS A FUNCTION OF TEMPERATURE AND PRESSURE AND CALCULATED THERMODYNAMIC QUANTITIES

An experimental approach was developed to measure the mutual solubilities of organic fluids and water over a wide range in temperature and pressure. By using a gold bag, rocking autoclave, and a precision high pressure liquid chromatography pump, samples of both equilibrated fluids may be obtained. Using this technique the solubility of liquid p-xylene in water was measured as a function of temperature and pressure from 298 to 423 K (at constant pressure) and from 0.1 to 50 MPa (at constant temperature). The results were used to calculate the partial molal thermodynamic quantities: Delta (G) over bar(soln), Delta (H) over bar(soln), Delta (S) over bar(soln), Delta (C) over bar(psoln), and Delta (V) over bar(soln). Calculated values for these quantities at 298 K are: Delta (G) over bar(soln) = 15.92 (+/-.13) kJ/mol,Delta (H) over bar(soln) = 1.643 (+/-.214) kJ/mol, Delta (S) over bar(soln) = -47.90 (+/-.72) J/mol-K, Delta (C) over bar(psoln) = 214.7 (+/-3.8) J/mol-K, and Delta (V) over bar(soln) = 31.08 (+/-3.80) cm(3)/mol.