THE TRANSFORMATION OF ETHANOL OVER ALPO4 AND SAPO MOLECULAR-SIEVES WITH AEL AND AFI TOPOLOGY - KINETIC AND THERMODYNAMIC APPROACH

The transformation of ethanol into ether and ethylene was studied over a series of aluminophosphates and silicoaluminophosphates with AFI an d AEL topology, at 593 K. It was found that the data followed a simple parallel kinetic scheme. The formation of ether, the less demanding r eaction, can be strongly limited by thermodynamics. Based on both the kinetic model and the equilibrium curve for the system considered, a s eries of parameters were defined in order to determine the relative st rength and concentration of the active centres participating in both r eactions. Differences in the average specific-activity for the ethanol transformation into ethylene (turnover-like number) were rationalised in terms of differences in the average hydrogen-atoms partial-charge. Structural influence on product distribution due to the shape-selecti ve phenomenon was not observed under the reaction conditions employed.