Although the preparation of ZSM-5@silicalite-1 (ZS) core-shell catalysts has been reported in the literature

their selectivity to para-xylene (PX) in the toluene alkylation with methanol is difficult to control. Here we present the effects of water and ZSM-5 adding amounts in the synthesis solution

the hydrothermal synthesis time

and the Si/Al ratio of core ZSM-5 on the catalytic performance of ZS core-shell catalysts. The ZS core-shell catalysts were characterized by X-ray diffraction (XRD)

N

2

adsorption

and NH

3

temperature-programmed desorption (NH

3

-TPD) techniques. The highest PX selectivity of 95.5% was obtained for the ZS (Si/Al=140) catalyst prepared in the synthesis solution with a molar ratio of 0.2TPAOH:1TEOS:250H

2

O at 175℃ and 10 r·min

-1

for only 2 h and the corresponding toluene conversion is as high as 22.8% for the alkylation of toluene with methanol.