Effect of the nonuniform dealumination on the acidity and catalytic activity of faujasite

Theoretical models are used to simulate aluminum distribution in a Y zeolite crystal when an aluminum gradient along the crystal is produced by dealumination. From these models, the theoretical distribution of different types of acid sites is calculated. The effect of the aluminum gradient along the crystal on the acid site distribution is discussed, and it can be related with the differences observed in cracking activity when the Y zeolite is dealuminated by different procedures.