What is aromatic nitration?
Answers
Answer:
Aromatic nitration is a class of industrially important reactions for the synthesis of chemical intermediates with direct relevance to dyes, plastics, and pharmaceuticals. The nitration reagent is a mixture of concentrated nitric and concentrated sulfuric acid (333). Obviously, a more benign route would be desirable.
Answer :
The industrial gas-phase nitration of aromatic compounds has increased significantly in the last decade.
Aromatic nitration is a class of industrially important reactions for the synthesis of chemical intermediates with direct relevance to dyes, plastics, and pharmaceuticals. The nitration reagent is a mixture of concentrated nitric and concentrated sulfuric acid (333). Obviously, a more benign route would be desirable.
Various solid acids including zeolites have already been screened for nitration with N2O5 or NO2/O3 as reagent, but poor selectivity because of overnitration to di-nitro aromatics is a problem (380,381). Since these observations were made, researchers have been trying to optimize the selectivity toward mono-nitrated products. Recently, Ma et al. observed high para-selectivity using H-beta as the catalyst and N2O5 as the nitrating agent (Scheme 9E) (382). In this case, the ortho-/para-selectivity could simply be tuned by changing the order of reagent addition.