A Study on the Templating Ability of Diquaternary Cations for the Zeolite Synthesis in Terms of Energetics

Computer simulation of the interactions of diquaternary cations with zeolites ZSM-50, NU-87, ZSM-23 and ZSM-12 is carried out to determine the templating ability of diquaternary cations in the formation of these zeolites. The calculated energies are a measure of match between the geometry of diquaternary cations and the topology of the zeolite framework. The systematic synthesis results of Mioni et al., especially the dependence of the products on the chain lengths of diquaternary cations are rationalized quantitatively. We infer that it is consistent with the templating theory of zeolite synthesis that ZSM-12 and ZSM-23 both can be formed by more than one type of diquaternary cations.