METHOD OF OBTAINING 21,4,41-TRINITROBENZANILIDE

FIELD: chemistry. ^ SUBSTANCE: invention concerns organic chemistry and method of obtaining 21,4,41-trinitrobenzanilide (TNBA), a semiproduct of 5(6)-amino-2-(4-aminophenyl)benzimidazol synthesis, applied as monomer in production of heat resistant and high-strength fibre. Method involves acylation of 2,4-dinitroaniline by 4-nitrobenzoilchloride taken in excess by over 5 mol % in relation to 2,4-dinitroaniline, at gradual temperature increase to boiling point at atmospheric pressure, in the presence of iron chloride as catalyst; separation of 21,4,41-trinitrobenzanilide by sequence of crystallisation, filtration and neutralisation by ammonium in water suspension. Mother solution formed after crystallisation and filtration is recycled at the next acylation stage, and neutralisation is performed at temperature under 60°C with dosed supply of aqueous ammonium solution. ^ EFFECT: efficient novel method of obtaining the compound. ^ 6 cl, 6 ex, 1 dwg, 1 tbl