Synthesis of 2,6-dimethylnaphthalene by methylation of 2-methylnaphthalene on mesoporous ZSM-5 by desilication

Mesoporous ZSM-5 was prepared by NaOH-treatment of ZSM-5 and examined for selective synthesis of 2,6-dimethylnaphthalene (2,6-DMN). The results showed that mesopores were formed owing to desilication. The catalytic activities and lifetime were significantly enhanced with increasing treatment time. About 37% 2-methylnaphthalene(MN) conversion, compared to 5.3% on parent ZSM-5, was obtained at 10.25 h on mesoporous ZSM-5 by 8 h NaOH-treatment. It is thought that mesopores in alkaline-treated ZSM-5 result in higher catalytic activities and longer lifetime. Higher 2,6-/2,7-DMN ratio, selectivity and yield of 2,6-DMN were obtained on modified mesoporous ZSM-5 with Zr.