Solubility of Ethylene in Mixtures of Toluene, Norbornene, and Cyclic Olefin Copolymer at Various Temperatures and Pressures

Abstract

In this study, the solubilities of ethylene in mixtures of toluene, norbornene, and cyclic olefin copolymer (COC) were measured at various temperatures (between 323.15 and 423.15 K), pressures (between 5 and 25 bar), concentrations of norbornene (between 0 and 85 wt %), and concentrations of COC (between 0 and 40 wt %). The experiments were conducted by the pressure decaying method using a newly designed apparatus. The experimental results show that the solubility of ethylene increases with increasing system pressure but decreases with increasing system temperature in the above mixture. Another interesting observation is that the solubility decreases when the concentration of reaction product, COC, is increased. Thus, in addition to temperature and pressure, the COC concentration affects the reaction extent, and beyond a certain COC concentration, further reaction favoring COC generation is impossible because of the opposite effect on ethylene solubility. Also, in this study, the experimental solubility data were expressed in vapor−liquid equilibrium relationship and correlated by bubble-pressure calculations with the Peng−Robinson equation of state (PR EOS; Peng, D. Y.; Robinson, D. B. Ind. Eng. Chem. Fundam. 1976, 15, 59) incorporating the modified van der Waals one-fluid (vdW-1) mixing rules and the Zhong−Masuoka (Z−M; Zhong C.; Masuoka, H. Fluid Phase Equilib. 1996, 123, 59) mixing rules, including the consideration of binary interaction parameters. The average absolute deviation percentages (AAD) of the correlation are less than 3.0%, except that of pressure with the Z−M mixing rules.