A DFT study of the cracking reaction of thiophene activated by small zeolitic clusters

A theoretical study of the cracking reaction of thiophene by small zeolitic cluster catalysts is reported. Cluster density functional theory calculati ons have been performed. It is shown that cracking of thiophene is catalyze d by Lewis basic oxygen atoms. Several active sites are proposed and tested . Moreover, it appears that the use of a partner molecule, strongly adsorbe d to the acidic proton, allows for an important decrease of the cracking ac tivation energy barrier. The effect of hydrogenation of thiophene prior to the cracking reaction has been checked. Interestingly, hydrogenation does n ot affect dramatically the activation energy barrier (-10 kJ/mol). However a large stabilization of the product of the reaction has been found (-40 kJ /mol). (C) 2001 Academic Press.