Para -selective nitration of bromobenzene catalyzed by Hβ zeolite with NO 2 and its theoretical studies

A novel heterogeneous catalytic system was developed for the preparation of para -nitrobromobenzene ( p -NBr) with nitrogen dioxide (NO 2 ) as nitrating agent in the presence of oxygen (O 2 ). By applying Hβ zeolite as the catalyst, p -NBr can be obtained with high conversion (85.7%) and selectivity (91.7%). In addition, it can be recycled at least five times without a significant decrease in catalytic activity, which demonstrates its high efficiency, good stability and regenerability. Meanwhile, DFT study explained the regioselectivity for the nitronium (NO 2 + ) nitration via electrophilic process, which support the experimental conclusion. Graphical abstract