Preparation of Hierarchical Zr-Beta Zeolites for the Green Synthesis of 2,4-Dimethoxyacetophenone via Friedel–Crafts Acylation

2,4-Dimethoxyacetophenone was synthesized with hierarchical Zr-Beta zeolites and no additional solvent through Friedel–Crafts acylation in this study. A “crystallization-etching-recrystallization” strategy was employed to synthesize the hierarchical Zr-Beta zeolites with a core–shell structure. Zirconium was uniformly incorporated into the Beta zeolites and formed stable Lewis acid sites. The etching and recrystallization processes significantly enhanced the hierarchical Zr-Beta zeolites, which possessed a high mesopore volume (0.40 cm 3 /g) and specific surface area (463.6 m 2 /g). The hierarchical Zr-Beta zeolites presented good catalytic performance in the solvent-free Friedel–Crafts acylation of m-dimethoxybenzene with acetic anhydride. The catalyst exhibited stable catalytic performance for the acylation with excessive acetic anhydride, showing minimal deactivation of catalytic performance (<5% activity loss) after four cycles. When the reaction temperature, catalyst dosage, and acetic anhydride-to-m-dimethoxybenzene molar ratio were set at 393 K, 4 wt%, and 3.5, respectively, both the m-dimethoxybenzene conversion and 2,4-dimethoxyacetophenone selectivity reached 100%. Besides, the hierarchical Zr-Beta zeolites had catalytic performance for the Friedel–Crafts acylation of anisole with acetic anhydride. Both the anisole conversion and the para-substituted product selectivity were 100%.