Simultaneous Isomerization and Etherification of Isoamylenes

Abstract

The etherification of isoamylenes (2-methyl-1-butene, 2M1B, and 2-methyl-2-butene, 2M2B) with methanol, ethanol, and n-propanol was studied using a commercial ion-exchange resin as a catalyst. The steady-state reaction rates for the formation of tert-amyl ethyl ether from isoamylenes and ethanol were measured in a continuous stirred tank reactor. At 333 K the reaction rate of the ether formation was measured to be zero order with respect to the ethanol (ETOH) and positive with respect to the olefin. Initial reaction rates for the simultaneous etherification and isomerization of 2M1B were measured in a batch reactor. Initial reaction rates measured at temperatures of 333 and 353 K showed that the different alcohols (methanol, ethanol, and 1-propanol) affected the isomerization rate but not the etherification rate. Measurements were also made with different initial ETOH/2M1B mole ratios. According to the results, etherification and isomerization rates are equal until the lowest mole ratio (0.2) is reached. It was also found that the reaction rates have a constant value at stoichiometric or higher ETOH/2M1B mole ratios. A new model was developed to explain the obtained results.