Improved Regioselective Mononitration of o-Xylene over HBEA-500 Zeolite Catalyst

Abstract

Nitration of aromatic compounds is one of the most fundamental and important reaction in organic synthesis, which provides key organic intermediates or energetic materials. 1-3 The traditional method for nitration, involving use of a mixture of nitric and sulfuric acids, though still in widespread commercial use, suffers from many disadvantages of classical nitration method including strong acidic media, formation of environmentally unfriendly waste that is expensive to dispose off, over nitration, low selectivity and safety problems. These disadvantages have encouraged extensive efforts to develop alternative methods 4-7 to replace conventional nitration. Current trends in the nitration of aromatics emphasized minimizing by product formation and improved regioncontrol of the desired product through the use of catalysts. Smith and coworks have utilized zeolites to enhance the para-selectivity in chlorination, 8 acylation, 9 and methanesulfonylation 10 of simple aromatic substrates. The present investigation was to develop a mild, easy to operate and efficient catalyst 11-14 without involving sulfuric acid and