The external surface of 2D(two-dimensional)ZSM-5 zeolite was passivated by fabricating full silica Silicalite-1 through secondary crystallization technique.The obtained catalysts were characterized by XRD,SEM,TEM,N2 adsorption-desorption isotherms,and Py-IR,etc.The catalytic performances of the surface passivated two-dimensional ZSM-5 zeolite in the alkylation between toluene and methanol were evaluated in a fixed-bed reactor.The characterization results showed that the full silica Silicalite-1 passivated 2D ZSM-5 zeolites with internal 2D lamellar structure were successfully constructed,and the Silicalite-1 not only effectively shielded the Brønsted acid sites on the external surface of 2D ZSM-5 zeolite and inhibited the occurrence of xylene isomerization,but also possessed the ability of shape-selectivity towards PX(p-xylene),which greatly improved the selectivity of p-xylene.The surface passivated 2D ZSM-5 zeolite also showed a long lifetime at 673K,and WHSV=10h-1,and maintained high activity after 40h,with the selectivity of p-xylene about 35%,indicating an excellent catalytic performance in the alkylation of toluene with methanol.The present research could accelerate the industrialization procedure of alkylation between toluene and methanol.
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