Synthesis of 2,6-Diisopropylnaphthalene over H-mordenite Catalyst Modified by Nitric Acid

The H-mordenites (HM) was dealuminated by nitric acid leaching. The naphthalene isopropylation reaction performance of the modified HM zeolite catalyst was investigated in a fix-bed reactor. Influences of different dealuminatation methods and Si/Al ratios on catalytic performances were analyzed. The results show that the catalytic selectivity of 2, 6-DIPN is increased after dealuminated by nitric acid leaching. A combination of hydrothermal treatment with nitric acid leaching can remove acid centre effectively, change ratio of B to L acid and acid strength distribution. The selectivity of 2, 6-DIPN is increased without decreasing naphthalene conversion rate. The increase of Si/Al ratio results in a slight decrease of catalytic activity and improvement of stability, the selectivity increased firstly and then decreased with increasing of Si/Al ratio. The optimized operating conditions for zeolite dealuminatation are as follows: HM zeolites is treated in 0.5 h~ -1 steam at 500 ℃ for 1.0 h, then is processed by nitric acid leaching at 45 ℃ for 24.0 h. The corresponding Si/Al ratio is 31 and 2, 6-DIPN yield is 7.24%.