METHOD OF PREPARING N-ALKYL-N'-PHENYL-OR N'N'- DIALKYL-p- PHENYLENEDIAMINES Russian patent published in 2001 - IPC

FIELD: chemical industry. SUBSTANCE: described is improved method of preparing N-alkyl- N'-phenyl or N,N'-dialkyl-p-phenylenediamines used as stabilizers. Method comprises alkylating p-aminodiphenylamine or pphenylenediamine with aliphatic C₅-C₁₀ alcohols at elevated temperature in the presence of caustic potassium, distilling the resulting azeotropic alcohol- water mixture during alkylation process through dephlegmator with heat carrier being heated to temperature of 115- 125 C, recycling condensed alcohol vapors to reaction zone, neutralizing reaction mixture with crystalline oxalic acid and isolating the desired product. Method makes it to reduce power intensiveness of process due to eliminating circulation of mixture of vapors of alcohol and alcohol-water azeotrope, optionally cooling it and subsequently heating and also to improve separation of azeotrope from alcohol vapors. EFFECT: more efficient preparation method. 7 ex, 1 tbl