The calculation of the selectivity at the nitration of alkylbenzens in the TFA
The nitration reaction of the alkylbenzenes (MePh, EtPh, n-PrPh, n-BuPh, i-PrPh) in the media of CF3COOH was studied. The experimental data on the selectivity of the nitration reaction in TFA was systematized. The σ-complexes of alkylbenzenes with the nitronium cation and the molecules of solvents were calculated applying the quantum chemistry programms (GAMESS/MOPAC). The selectivity inversion of the nitration reaction under solvent action as well as the correlation of position selectivity on steric factors of alkyl substitutes Es0 has been predicted applying the semi-empirical method AM1. The semi-empirical method (PM3) described the selectivity of the nitration reaction in approximation of localization worse.