A COMPARATIVE THERMODYNAMIC AND KINETIC-STUDY OF THE REACTION BETWEENOLEFINS AND LIGHT ALCOHOLS LEADING TO BRANCHED ETHERS - REACTION CALORIMETRY STUDY OF THE FORMATION OF TERT-AMYL METHYL-ETHER (TAME) AND TERT-BUTYL ISOPROPYL ETHER (IPTBE)

The liquid-phase additions of isopropyl alcohol to isobutene to give t ert-butyl isopropyl ether (IPTBE) and of methanol to a mixture of 2-me thyl-2-butene (2M2B) and 2-methyl-1-butene (2M1B) to give tert-amyl me thyl ether (TAME) have been studied in a calorimetric reactor. The hea t capacity of IPTBE and TAME and the enthalpy change associated with t he IPTBE and TAME synthesis reactions have been determined. At 343 K, the standard molar reaction enthalpy for TAME formation from 2M1B is - 34.9 +/- 2.5 kJ.mol(-1) and from 2M2B is -27.1 +/- 2.5 kJ.mol(-1). At 298 K, the standard molar enthalpy for IPTBE formation is -21.7 +/- 1. 6 kJ.mol(-1). A determination of the apparent activation energy of 70. 3-78.4 kJ.mol(-1) for the IPTBE synthesis has been performed graphical ly from the plots of heat flow rate vs time. TAME heat capacity in the liquid phase has been found to follow the equation C-p (J.mol(-1).K-1 ) = 1059.5-6.1271(T/K) + 1.1093 x 10(-2)(T/K)(2) and that of IPTBE the equation C-p (J.mol(-1).K-1) = 1181.5-6.7818(T/K) + 1.2186 x 10(-2)(T /K)(2). Comparison of thermodynamic and kinetic data obtained for the IPTBE system with that previously reported for tert-butyl methyl ether (MTBE) and tert-butyl ethyl ether (ETBE) is also performed.