Nitrating benzo-tri:fluoride(s) to mono- or di-nitro derivs. - using conc. sulphuric acid contg. sulphur tri:oxide and excess nitric acid

摘要

Benzotrifluorides of formula (I) (where X1 and X2 are H or halogen and Y1 is H, -NO2 or -CF3) are nitrated with a mixt. of concn. HNO3 and conc. H2SO4 contg. SO3. An excess of 1-3 mol HNO3 is used, at increasing temp. within 70-130 (85-120) degrees C range, in 5-8 (6-7) hrs. Prods. can be mono- and dinitrated (I) of formula (II) (where R is H or -NO2). (II) contg. 2-NO2 gps. in m-position can be prepd. (II) are intermediates for dyes or polyamides E.g. (i) amines, which are diazo components for dyes, are prepd. by substituting 1 halogen atom by NH3. (ii) Amines used as starting materials for polyamides are prepd. by reducing the -NO2 gps. HNO3 decompsn. and nitrous gas generation is very small, and high conversion and yields (e.g. 84-98%) are achieved.