Metal salts with highly electronegative cations as efficient catalysts for the liquid-phase nitration of benzene by NO2 to nitrobenzene

Metal salts with highly electronegative cations have been used to effectively catalyze the liquid-phase nitration of benzene by NO 2 to nitrobenzene under solvent-free conditions. Several salts including FeCl 3 , ZrCl 4 , AlCl 3 , CuCl 2 , NiCl 2 , ZnCl 2 , MnCl 2 , Fe(NO 3 ) 3 ∙9H 2 O, Bi (NO 3 ) 3 ∙5H 2 O, Zr(NO 3 ) 4 ∙5H 2 O, Cu(NO 3 ) 2 ∙6H 2 O, Ni (NO 3 ) 2 ∙6H 2 O, Zn(NO 3 ) 2 ∙6H 2 O, Fe 2 (SO 4 ) 3 , and CuSO 4 were examined and anhydrous FeCl 3 exhibited the best catalytic performance under the optimal reaction conditions. The benzene conversion and selectivity to nitrobenzene were both over 99%. In addition, it was determined that the metal counterion and the presence of water hydrates in the salt affects the catalytic activity. This method is simple and efficient and may have potential industrial application prospects.