Abstract
Nitration of o-xylene with nitrogen dioxide imparts remarkable selectivity to 4-nitro-o-xylene. The addition of Brønsted acids and Lewis acids can effectively improve the selectivity for 4-nitro-o-xylene and/or yield, and the Lewis acids present a better influence on the reactions than Brønsted acids do. A 71% yield of mononitro-o-xylene with high selectivity for 4-nitro-o-xylene (ratio 4-/3- = 3.91) has been achieved by the assistance of bismuth trichloride under solvent-free conditions.
GRAPHICAL ABSTRACT
Notes
a All reactions were carried out with 5.0 mmol of o-xylene for 12 h, unless otherwise noted.
b Based on o-xylene and determined by calibrated quantitative GC analysis using an internal standard.
c Absolute yield (internal standard) based on o-xylene.
d Reaction time 24 h.
a All reactions were carried out with 5.0 mmol of o-xylene at room temperature for 12 h, unless otherwise noted. The definitions of conversion and product yield are consistent with Table 1.
b Relative to o-xylene.
a All reactions were carried out with 5.0 mmol of o-xylene at room temperature, unless otherwise noted. The definitions of conversion and product yield is consistent with Table 1.
b Relative to o-xylene.
c Dichloromethane (3 mL) was added as solvent.
Color versions of one or more of the figures in the article can be found online at www.tandfonline.com/lsyc.