| 摘要 |
This invention relates to methods of controlling the oxidation of cyclohexan e to adipic acid in the presence of a monobasic acid solvent, by separating th e catalyst from the reaction mixture, outside the reaction zone. Substantially all the unreacted cyclohexane, the majority of adipic acid, and substantiall y all the monobasic acid solvent are preferably removed. A protic solvent, may be added intermittently or continuously in the reaction mixture during the removal of the monobasic acid solvent, preferably by distillation, for preventing solids precipitation. A dipolar aprotic solvent is then added in the presence of an adequate amount of the protic solvent to maintain a singl e liquid phase, followed by a step of formation of two liquid phases, a solids - free protic liquid phase containing substantially all the catalyst, and a solids-free aprotic liquid phase containing at least the majority of ingredients of the reaction mixture. The formation of the two phases is performed by a process selected from a group consisting of lowering the firs t temperature to a second temperature, adding additional protic solvent, addin g an apolar aprotic solvent, and a combination thereof.
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