Separation of dinitronaphthalene: Crude mixtures of dinitronaphthalene (5 g, from Table-3 run 8) was placed together with 50 mL acetone in a 100 mL flask, stirred and heated to reflux. The suspension was refluxing for 2 h and then cooled to 30 oC by stirred and filtered quickly. The precipitate was recrystallized by acetone and 1,5-dinitronaphthalene as light yellow crystals (1.725 g) was got. Then the filter liquor was concentrated to one-thirds of original volume, filtered, the precipitate was recrystallized by toluene and 1,8- dinitronaphthalene as light yellow crystals (1.987 g) was got.
1, 5-Dinitronaphthalene: m.p. 215-216 oC, 1H NMR (400 MHz, CDCl3): δ = 7.84 (t, 2H), 8.33 (d, 2H), 8.81 (d, 2H).
1, 8-Dinitronaphthalene: m.p. 172-173 oC, 1H NMR (400 MHz, CDCl3): δ = 7.98 (t, 2H), 8.51 (dd, 4H).
Zeolite-Assisted Regioselective Synthesis of Dinitronaphthalene 
