Transalkylation of C10 aromatics with 2-methylnaphthalene for 2,6-dimethylnaphthalene synthesis: High-efficiently shape-selective & synergistic catalysis over a multifunctional SiO2-Mo-HBeta catalyst

High-efficiency transalkylation of low-value C 10 A with 2-MN in H 2 atmosphere was achieved for the synthesis of 2,6-DMN, depending on the shape-selective & synergistic catalysis over a multifunctional SiO 2 -Mo-HBeta catalyst with.three kinds of active sites located only inside the 12-ring channel. • C 10 A transalkylation with 2-MN occurred on multifunctional SiO 2 -Mo-HBeta in H 2 flow. • Synergic catalysis of three kinds of internal active-sites promoted transalkylation. • Transition-state shape-selectivity & diffusion-constraint suppressed side-reactions. • Coking deactivation was prevented especially by catalytic hydrogenation of olefins . • 2,6-DMN yield of above 9.7% was obtained during the 50 h on-stream reaction. A new process for the low-cost synthesis of 2,6-DMN, the high-efficiency transalkylation of C 10 aromatics (C 10 A) with 2-MN in H 2 atmosphere was developed depending on a multifunctional SiO 2 (Ⅱ)-3.0%Mo-HBeta catalyst with three kinds of active sites located only inside its 12-ring channels. Firstly, the high-efficient synergistic catalysis from metal-Mo monomer and Lewis & Bronsted acid-sites significantly improved transalkylation, attributed to a surface behavior (involving hydrogen spillover) may producing the active hydrogen-species which markedly enhance the proton-transfer efficiency in this proton-acid catalytic reaction. Secondly, the hydrogenation & subsequent ring-opening etc. side-reactions of naphthalene series and the formation of multi-alkylnaphthalene byproducts were almost completely suppressed due to both the passivation of the external surface of catalyst and the transition-state shape-selectivity & the diffusion-constraint effect inside pores. Besides, both the reasonable catalytic-hydrogenation (from metal-Mo monomer) immediately converting light olefins (from dealkylation) into alkanes and the transition-state shape-selectivity suppressing the formation of larger-molecular multi-alkylnaphthalenes in channels, effectively prevented from the coking-deactivation of catalyst. As a result, the 2-MN conversion of above 75.3% and the 2,6-DMN yield of above 9.7% were obtained during the 50 h on-stream reaction. Our work may provide a promising model for rationally designing the elegant catalyst for a complicated conversion reaction.