A multi-technique approach to disclose the reaction mechanism of dimethyl carbonate synthesis over amino-modified SBA-15 catalysts

A series of amine-modified SBA-15 was employed as catalysts in the carbonate interchange reaction of ethylene carbonate (EC) with methanol to produce dimethyl carbonate (DMC). These materials exhibited good catalytic performances that strongly depended on the reaction temperature. A multi-technique approach was employed to disclose the role played by the different amine chains in driving the whole reaction. To this purpose, in situ FT-IR experiments were combined with theoretical calculations in order to explain the catalytic results observed in the presence of catalysts with different basic strength. A close correlation was found between the number and the nature of the alkylamine chains present in the SBA-15 pores and the capacity of the catalyst to activate the reagent molecules, as well as to stabilize the reaction intermediate. It was demonstrated that the ability of the catalyst to dissociatively adsorb methanol is the key factor for the proper choice of the catalytic system. Moreover, the capacity of the catalyst to stabilize the reaction intermediate has to be considered to allow the reaction to proceed so obtaining the desired final product (DMC).