Phase Equilibrium Data of Tetrabutylurea, Tetramethylurea, and Tetramethylthiourea/Carbon Dioxide at Pressures up to 200 bar at 313.15 and 333.15 K

Abstract

High-pressure phase equilibrium (vapor−liquid and solid−supercritical fluid phase equilibria) data for three binary systems were determined at two temperatures (313.15 and 333.15 K) and at pressures of carbon dioxide of up to 250 bar for tetrabutylurea/carbon dioxide, up to 200 bar for tetramethylurea/carbon dioxide, and up to 110 bar for tetramethylthiourea/carbon dioxide using a variable-volume high-pressure optical view cell. The measurements have been performed for all of the three systems at a constant temperature with increasing pressure. Furthermore, a melting point curve (solid−supercritical fluid phase equilibrium) of the solid sample tetramethylthiourea was determined using the modified capillary method in a high-pressure optical view cell at a pressure of carbon dioxide of up to 300 bar. The highest mutual solubilities for these binary systems under the same process conditions were in the following order: tetrabutylurea/carbon dioxide > tetramethylurea/carbon dioxide > tetramethylthiourea/ carbon dioxide. The results determined with the modified capillary method showed that at a pressure higher than 10 bar, the liquefaction temperature decreased significantly.

P-x,y Equilibrium Data of the Binary Systems of 2-Propanol, 1-Butanol and 2-Butanol with Carbon Dioxide at 313.15 K and 333.15 K

“… A scheme of a variable-volume high-pressure optical view cell for the determination of the solubility of argon-butanol isomer systems: 1-driven gas booster; 2-argon supply valve and valve for gas-rich phase sampling; 3-glass trap for sampling; 4-gas flow meter; 5-optical view cell; 6-propeller mixer; 7-glass trap for sampling; 8-gas flow meter [ 24 ]. …”

“… Side view of a scheme of a variable-volume high-pressure optical view cell with a hydraulic sapphire piston system [ 24 ]. …”

Determination of Viscosity, Density and Interfacial Tension of the Carbon Dioxide–Isopropanol, Argon–Isopropanol, Sulphur Hexafluoride–Isopropanol Binary Systems at 313.15 K and 333.15 K and at Elevated Pressures

“…A variable-volume high-pressure optical view cell described previously by Borjan et al (2022) was used for the determination of viscosity [20]. The calculation of nondimensional numbers, both Reynolds and Newton, from the measured voltage, mixing, and electric current, was employed for the determination of the viscosity of two binary gas-saturated isopropanol systems [21].…”