L. Sola et al., THERMODYNAMIC AND KINETIC-STUDIES OF THE LIQUID-PHASE SYNTHESIS OF TERT-BUTYL ETHYL ETHER USING A REACTION CALORIMETER, Industrial & engineering chemistry research, 34(11), 1995, pp. 3718-3725
The liquid-phase addition of ethanol to isobutene to give tert-butyl e
thyl ether (ETBE) on the ion-exchange resin Lewatit K2631 has been stu
died in a calorimetric reactor. The heat capacity of ETBE and the enth
alpy change of the ETBE synthesis reaction in the temperature range 31
2-333 K have been determined. ETBE heat capacity in the liquid phase h
as been found to follow the equation C-p (J . mol(-1). K-1) = 486.73 -
2.253 (T/K) + 0.00479 (T/K)(2). At 298 K the standard molar reaction
enthalpy is Delta H degrees = -32.0 kJ . mol(-1). A determination of t
he apparent activation energy of 86.5-89.2 kJ . mol(-1) has been perfo
rmed graphically from the plots of heat now rate versus time. An Eley-
Rideal mechanism, with two active sites involved in the rate determini
ng step, has been proved to be correct. From this model an apparent ac
tivation energy of 80.6 kJ . mol(-1) is deduced. A -3.0 kJ . mol(-1) v
alue has been found for the adsorption enthalpy of ethanol. This allow
s the estimation of the actual gel-phase activation energy of 77.6 kJ
. mol(-1).