The selectivity during the n-butene interconversion depends neither on the fouling of a commercial silica-alumina cracking catalyst with a heterogeneous active surface, nor on the pressure between 32 and 750 torr over a SO3H resin (Amberlyst 15). These observations confirm the assumption of a common surface intermediate which presumably is the sec-butyl carbonium ion. Nevertheless, the selectivity can phenomenologically be given with high accuracy by the differential equations for a triangle reaction scheme involving first order steps. Formally identical equations can be derived on the assumption of a common intermediate. The rate constants for adsorption and desorption have been calculated from the kinetic equations. The activation energies are 13 kcal/mole for 1-butene adsorption, and 22 kcal/mole for desorption into 1-butene. The surface coverages can be determined, too, provided the sites of the resin are of the same activity. The values are between 0.1 and 0.9.
ASJC Scopus subject areas
- Physical and Theoretical Chemistry