A clean method for solvent-free nitration of toluene over sulfated titania promoted by ceria catalysts

A mild simple method for nitration of aromatic compounds, various solid acids as catalysts, the air treated with the corona discharge generator as nitrating agent, the liquid-phase nitration of toluene, at ambient temperature and atmospheric pressure without solvent has been investigated. The results show that SO42-/TiO2 (ST) and SO42-/TiO2 doped with CeO2 (STC) catalysts displayed good nitration activity in the experiments. It is an attractive method for the environmentally friendly synthesis of nitroaromatic compounds. Moreover, only mononitrotoluenes were detected in the products, and the ratio of paranitrotoluene and ortho-nitrotoluene was approximately 1:1 with various catalysts. A maximum yield of about 11.4% was achieved for mononitrotoluenes in STC reaction system in 3 h. (C) 2009 Elsevier B.V. All rights reserved.