METHOD OF PREPARING N,N'-SUBSTITUTED PIPERAZINES Russian patent published in 2000 - IPC

FIELD: chemical industry. SUBSTANCE: described is method of preparing N,N'-substituted piperazines. Said compounds are used as stabilizers for polymeric materials of general and special purposes. Said compounds are effective addition agents to lubricating oils and also additives to petroleum products which passivate variable valency metals. Described is method of preparing N, N'- substituted piperazines of general formula I: wherein = R¹-R²-alkyl C₁-C₄ alkyl, phenyl, alpha-methyl benzyl, cumyl, cyclohexyl by reacting 2,6-disubstituted phenol with formaldehyde and piperazine at molar ratio thereof of 1.0:1.0-1.2: 0.5-0.6 in aliphatic C₁-C₄ alcohols during heating operation by addition of formaldehyde to solution of 2,6-disubstituted phenol and piperazine in aliphatic alcohol, and subsequently maintaining reaction mixture. Formaldehyde is added at 65-130 C for 0.5-1.0 h, and the resulting mixture is then maintained for 0.5-2.0 h. EFFECT: shorter process duration and increased yield and improved quality of the desired product. 13 ex, 1 tbl