Effective diffusivities and adsorption equilibrium constants of methanol, ethanol and 2-methyl-2-butene (2M2B), in Amberlyst 15, were evaluated from batch adsorption experiments. Moment expressions derived for different models involving diffusion resistances in the macropores and within the gel-like micrograins were used for the evaluation of effective diffusion coefficients. Contribution of surface diffusion to diffusion flux within the macropores was found to be quite significant. Also, it was found that diffusion resistance in liquid filled macropores was much more significant than diffusion resistance within the gel-like micrograins of Amberlyst 15., for methanol, ethanol and 2M2B.

Adsorption equilibrium constants of ethanol, methanol, isobutylene, isoamylenes (2M2B, 2M 1 B), MTBE and TAME on Amberlyst 15 catalyst were evaluated from the packed bed moment technique. Adsorption equilibrium constants of alcohols were found to be two orders of magnitude greater than the adsorption equilibrium constants of i-olefins and the corresponding tertiary ethers. However, their apparent heat of adsorption values are quite low ( 4 , 7 kJ/mol and -8.3 kJ/mol for methanol and ethanol, respectively). Among the i-olefins, isobutylene gave the highest adsorption equilibrium constant and the heat of adsorption (-54.2 kJ/mol). The adsorption equilibrium constant of 2M2B on a catalyst, which was pretreated with ethanol, was about three times greater than the corresponding value obtained on fresh catalyst. Second moment analysis indicated that diffusion resistance in both macropores and microspheres of the catalyst are equally significant.Les constantes d'equilibre d'adsorption de I'ethanol, methanol, isobutylene, isoamylene (2M2B, 2M 1 B) MTBE et TAME, avec le catalyseur Amberlyst 15,ont ete evaluees par la methode du moment de couche. Les constantes d'equilibre d'adsorption des alcools ainsi determinees sont superieures de deux puissances (1 02) aux valeurs correpondantes pour des olefines i et ethers tertiaires equivalents. Cependant, leurs valeurs apparentes de chaleur d'adsorption sont assez basses, (-6.7 kJ/mol et -8.3 kJ/mol, respectivement pour le methanol et I'ethanol). En ce qui concerne les olefines i, l'isobutylene a des constantes d'equilibre et de chaleur d'adsorption les plus elevees (-54,2 kJ/mol). La constante d'adsorption du 2M2B sur un catalyseur pretraite I'ethanol, est environ 3 fois superieure celle obtenue avec un catalyseur frais. Une analyse avec le moment du 2e ordre indique que la resistance la diffusion est la mme dans les macropores et les microspheres du catalyseur. E , = macroporosity of the catalyst 4 = microporosity of the catalyst E, , = bed void fraction pi = first absolute moment, (s) c'; = second central moment, (s2) v = kinematic viscosity, (m2/s) 3 = density of microspheres of catalyst, (kg/m3) z

: Etheriücation of reactive oleüns available in light ýuidized catalytic cracking (FCC) gas-C 5 oline is an attractive way to decrease the oleüns and to increase the octane number. The reactivities of 2-methyl-1-butene (2M1B) and 2-methyl-2-butene (2M2B) in the etheriücation reaction with ethanol catalysed by a strongly acidic macroreticular resin catalyst were investigated in a temperature range of 333-360 K using a liquid phase diþ erential ýow reactor. In the presence of excess alcohol, the apparent reaction orders of etheriücation reactions of isoamylenes were found to be 0.93 and 0.69 with respect to 2M1B and 2M2B concentrations, respectively. 2M1B was shown to be more reactive than 2M2B and its activation energy is also lower in the etheriücation reaction. It was also shown that diþ usion resistances, especially in the macropores of the catalyst, may play an important role on the observed rates.

No abstract