High-pressure phase equilibria and thermodynamic modeling for binary systems of light paraffins and aluminum alkyls

A continuous-flow apparatus was used to measure vapor-liquid equilibrium da ta at 398 K for the propane-triethylaluminum (TEA) and propane-tributylalum inum (TEA) systems. The pressures ranged from 31.0 to 55.2 bar for the prop ane-TEA system and 44.8 to 58.3 bar for the propane-TEA system. Equilibrium vapor- and liquid-phase compositions were obtained at selected pressures b y a gravimetric method. A thermodynamic model was developed to correlate th e vapor-liquid equilibrium data for the ethane-TEA, ethane-TEA, and ethane- trihexylaluminum (THA) systems that were previously measured and the propan e-TEA and propane-TEA systems. Each system consists of the light paraffin a nd an equilibrium mixture of the aluminum alkyl monomer and dimer species. The Peng-Robinson cubic equation of state was used to calculate the equilib rium phase compositions. The necessary parameters for the equation of state were obtained from thermodynamic data of other investigators coupled with a group contribution method. (C) 1999 Elsevier Science B.V. All rights rese rved.