| 摘要 |
A method for the production of 5-t-butyl-3-alkyl-phenols (I) involves recycling the monobutylated products from various alkylation, isomerization or cleavage reactions, optionally further concentrating (I), reacting with metal hydroxide, removing volatiles, reacting the salt with acid and isolating pure (I) by distillation. A method for the production of 5-t-butyl-3-alkyl-phenols (I) involves: (1) separation and recycling of the monobutylated meta-alkylphenols from: an equilibrium reaction mixture obtained from the acid-catalysed alkylation of 3-alkylphenols with isobutene; an equilibrium mixture obtained from the isomerization of 3-alkyl-6-t-butyl-phenols; or an equilibrium mixture obtained from the acid-catalysed cleavage of isobutene from 4,6-di-t-butyl-3-alkyl-phenols or 6-tert.-butyl-3-alkylphenols or from a mixture of these butylated phenols; (2) concentration of the 5-tert.-butyl-3-alkyl-phenols (I) formed again in the recycling of monobutylated alkyl-phenol isomers to 5-30 wt% in the mono-butyl-alkyl-phenol stream (only if the content of (I) in the equilibrium reaction mixture is not more than 5 wt%); (3) conversion of (I) in the resulting monobutyl- 3-alkyl-phenol mixture into the corresponding metal salt by reaction with metal hydroxides; (4) isolation of the non-volatile metal salt of (I) by distillation of volatiles; (5) treatment of the metal salt with acid; and (6) isolation of pure (I) by distillation.
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