Shape-selective isopropylation of 2-methylnaphthalene over modified HM catalysts

A series of HM catalysts modified with CeO₂ and MgO were prepared by impregnation method. Isopropylation reaction of 2-methylnaphthalene (2-MN) with isopropanol to 2-methyl-6-isopropylnaphthalene (2, 6-MIPN) catalyzed by modified HM catalyst was carried out in fixed-bed down-flow reactor. The results showed that the optimal reaction conditions of 2-MN isopropylation were the reaction pressure of 2 MPa, reaction temperature of 200°C, n(2-MN):n(i-PrOH):n(Cyclohexane)=1:3:70. Under the optimal conditions and over 20%CeO₂/HM catalyst, 2-MN conversion reached 37.7%, 2, 6-MIPN selectivity and yield were 83.0% and 28.7%, respectively, after 8 h reaction on stream, and over the HM catalyst modified by CeO₂ and MgO, the selectivity of 2, 6-MIPN could reach 89.5%. The reason is that CeO₂ and MgO can decrease the internal and external acid sites of HM catalysts, reduce the non-shape-selective reaction and improve the selectivity to 2, 6-MIPN.