(222at) Phase Behavior of Quaternary System of TAME Synthesis Under Reactive Distillation Conditions

Etherification of light gasoline is a kind of promising method for raising octane number. This reaction is reversible and exothermic so that it is beneficial to conduct the etherification in a reactive distillation column. There is complex phase behavior in the reactive distillation column as the vapor-liquid phase equilibria and the reactions affect each other.

Etherification of methanol with 2-methyl-1-butylene and 2-methyl-2-butylene to Tert-Amyl Methyl Ether (TAME) is the major chemical reaction among the etherification of light gasoline. In this paper, experiments of vapor-liquid phase equilibria of the quaternary system, including methanol, TAME and the two isoamylenes, were performed in a circulative vapor-liquid equilibrium cell containing sulfonic resin catalysts. The vapor-liquid phase behaviors coupled with the chemical reaction were investigated at the temperature of 338.15K and 348.15K. The reactive equilibrium constants at the bubble-point temperature and equilibrium pressure were calculated. The activity coefficient models, including Wilson, NRTL and UNIQUAC, as well as the SRK equation of state were used to correlate the experimental data respectively. The results have shown very good thermodynamic consistency and better agreement of Wilson predictions with the experimental data. This study provides important thermodynamic information for the process design of etherification reactive distillation of light gasoline.