Vapor-liquid equilibria of binary and ternary systems containing carbon dioxide, alkane, and benzothiophene

Experimental vapor-liquid equilibrium (VLE) data of binary and ternary systems are reported covering all of the phase envelopes up to near the critical point. The carbon dioxide + dodecane, carbon dioxide + benzothiophene, and carbon dioxide + nonane + benzothiophene systems were studied at (318.14, 344.75, 373.23, and 417.91) K, 373.93 K, and (313.09, 343.73, and 373.74) K, respectively. The apparatus is based on the static-analytic method with an on-line ROLSI (rapid on-line sampler-injector) sampler to allow fast determination of the VLE. Standard uncertainties for the measured properties in this work were estimated to be p ± 0.01 MPa, T ± 0.03 K, liquid mole fraction x_CO2 ± 0.0036, and vapor mole fraction y _CO2 ± 0.0016. The experimental VLE data for carbon dioxide + dodecane were found to be in agreement with those available in the literature at 318 K. Furthermore, the corresponding results for the ternary system indicate a high selectivity of nonane in the vapor phase instead of benzothiophene. Data obtained in this work were correlated with the Peng-Robinson equation of state using the Wong-Sandler mixing rules.