Bubble point pressure measurement and prediction of VLE and VLLE for dimethyl ether - 2-butoxyethanol and dimethyl ether - water - 2-butoxyethanol at (293.15 to 313.15) K

Abstract

Bubble point pressure was measured for a binary, dimethyl ether – 2-butoxyethanol, and a ternary, dimethyl ether – water – 2-butoxyethanol, by use of a static apparatus with a glass cell up to 837.0 kPa at (293.15 to 313.15) K. The mole ratios of water: 2-butoxyethanol were set to 50.0:50.0, 90.0: 10.0 and 95.0: 5.0 in the liquid phase for the ternaries. The phase behavior was visually observed through the glass cell at the pressure measurements, because the vapor-liquid-liquid equilibria (VLLE) have been reported for dimethyl ether -water. The binary showed the vapor-liquid equilibrium (VLE), which almost followed an ideal solution. 2-Butoxyethanol enhanced the miscibility range for dimethyl ether – water. Only the VLE was observed in the two ternaries with water: 2-butoxyethanol = 50.0: 50.0 and 90.0:10.0. The VLLE was partly observed in the ternary with water: 2-butoxyethanol = 95.0: 5.0. The NRTL equation was employed to correlate the VLE and the VLLE not only for dimethyl ether – 2-butoxyethanol but also for the other constituent binaries, dimethyl ether - water and water – 2-butoxyethanol. The NRTL equation provided good reproducibilities for dimethyl ether - 2-butoxyethanol with the average value of the absolute relative deviations (AARDs) of 0.90 % for the pressure. Using the parameters fitted with the constituent three binary data, the AARDs were 5.04 %, 6.80 % and 12.21 % for the pressure of dimethyl ether – water – 2-butoxyethanol with water: 2-butoxyethanol = 50.0: 50.0, 90.0: 10.0 and 95.0: 5.0, respectively. The experimental data and the prediction will contribute to design the sprays using water-based solvents for color paints, disinfectants, cleaning agents, cosmetics, pharmaceuticals and so on.