trifluoroacetic acid in dichloromethane T=25°C; 1 h; Irradiationreaction temperature varied: -50 to 25 deg C; time: 0.25 to 6 h; solvent also acetonitrile; trifluoroacetic acid concn. 0-1.0 mol dm-3; nitration also by NO2 or HNO3; Product distributionMechanism;