ZEOLITE BALL-MILLING AS A MEANS OF ENHANCING THE SELECTIVITY FOR BASE-CATALYZED REACTIONS

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