A novel method to prepare shape-selective catalysts by complexation–impregnation

The MgO/MCM-22 catalysts were prepared by complexation–impregnation method and their shape-selective performances in the synthesis of para-dialkylbenzenes by alkylation of alkylbenzenes were investigated. Characterization results indicate that the dispersion of the Mg2 + complex is limited to the external surface of the zeolites during complexation–impregnation process, and this results in the nearly complete coverage of the external Brønsted acid sites. Consequently, the shape-selective catalysts prepared by complexation–impregnation method have improved shape-selectivity and maintain the high catalytic activity. Compared with the conventional method for preparation of shape-selective catalysts, the strategy developed here is simple and efficient.

Graphical abstractComplexation–impregnation limits a complex to the external surface of the zeolite, which effectively improves the para-selectivity without decreasing the catalytic activity.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Shape-selective catalyst MgO/MCM-22 is prepared by complexation–impregnation method. ► Coverage of external acid sites and protection of inner acid sites on zeolite are achieved. ► Improvement in shape-selectivity and high catalytic activity is obtained.