Dynamic Lewis and Brønsted Synergistic Mechanism in Ga-Modified Hβ Molecular Sieves: Selective Synthesis of 2-Ethylanthraquinone Driven by Electron Redistribution

The precise regulation of multistep reaction paths in the synthesis of 2-ethylanthraquinone, with lower yields due to contradictions in the stability of intermediates and compatibility of active sites, poses a great challenge to industrial production. In this study, an electron redistribution strategy is proposed: By anchoring the active metal gallium to the Hβ molecular sieve framework, a Lewis and Brønsted acid pair that can dynamically adapt the reaction path is constructed. Based on the Friedel–Crafts acylation reaction, it was revealed that the Ga3+ center undergoes a valence transition during the catalytic process, which synergizes with the Brønsted acidic site (Si–OH-Al) to regulate the adsorption configuration of the intermediates, and improves the catalytic efficiency of the modified Hβ molecular sieves. Compared to the conventional sulfuric acid method (E = 5.2), a yield of 89.3% was achieved with an E coefficient of 0.8, a reduction of 85%. By optimizing the reaction temperature to 250 °C (300 °C for the acid-catalyzed method), energy consumption was reduced by 37%, while sulfonation waste was reduced by 1.6 tons per ton of product. The hierarchical pore structure of Ga–Hβ enhanced molecular diffusion efficiency, reducing activation energy by 35% (40.07 kJ·mol–1 for Ga–Hβ vs 62.11 kJ·mol–1 for H2SO4) and enabling four stable regeneration cycles with 80% activity retention. It provides a universal theoretical framework for space-time regulation of multistep catalytic networks in complex organic synthesis and provides a new direction for industrial catalytic synthesis of 2-ethylanthraquinones.