A computational study on the adsorption of the major ring-transformation products of methyloxirane in HY and HZSM-5 zeolites

摘要

The adsorption of dioxolane and dioxane derivatives in HY and HZSM-5 zeolites was studied computationally. The molecules are the main ring-transformation products of methyloxirane over these zeolites. Experimental work showed that the cyclic dimerisation reaction starts with the adsorption of the monomers over Brønsted acid sites through their ring oxygens. Computations revealed that these sites were close enough even in the high-silica HZSM-5 zeolite and the dimers comfortably fit even in the β-cage of HY as well as in the channel of the HZSM-5 zeolites. The stereochemical outcome of the dimerisation was also studied and the optimum conformations of the dimers were calculated as well.