No abstract

A new methylation (2-methylnaphthalene (2-MN) with methanol) process using low-value C 10 aromatics (C 10 A) as solvent and transmethylation-agentia was developed for the lower-cost synthesis of 2,6-dimethylnaphthalene (2,6-DMN), by using a ZSM-5/Beta composite catalyst. Especially, there is a peculiar subarea-catalysis over this catalyst due to both the reactant/product shape selectivity and the ingenious acidity design. Concretely, methylation (2-MN with methanol) and transmethylation (C 10 A with 2-MN) are catalyzed by the weak + medium + strong acid sites inside 12-ring pore and on the external surface of zeolites, while almost no transmethylation (but methylation and second shape-selective isomerization of fatter DMNs to β,β-DMN) occurs inside the smaller 10-ring pore (rejecting larger-molecular C 10 A) with mainly weak−medium acidity. Here, both the high-efficiency synergy of methylation with transmethylation and the meritorious isomerization incubated a 2-MN conversion of 52.98% and a 2,6-DMN yield of 11.01%. Our work may provide a promising model for the rational design of an excellent catalyst for a complicated reaction system.