Zeolite ball milling as a means of enhancing the selectivity for base catalyzed reactions Original Research Article

High energy ball milled KNaX zeolites were characterized using X-ray diffraction, BET, and FTIR techniques. The alkylation of toluene with methanol was chosen as a probe reaction for catalytic testing. Ball milling results in the collapse of the zeolite crystalline structure and its transformation into an XRD amorphous phase. Proper ball milling was shown to enhance the catalytic selectivity towards the formation of ethylbenzene + styrene during the alkylation. It was concluded that proper milling can moderately decrease both the Lewis base and Lewis acid sites concentration in alkali exchanged faujasite zeolites while deeply decreasing the strong Bronsted acid site density. The formation of xylenes is mainly dependent on Bronsted acid but not on Lewis acid site centers.