| 摘要 |
A cleavage method of bisphenols capable of yielding a product containing high-purity isopropenylphenol and phenol is disclosed, including (1) a cleavage step of supplying the mixture containing bisphenols together with chroman derivatives and flavan derivatives formed as by-products in the production process of bisphenols to a cleaving vessel and carrying out a cleavage reaction in the presence of a basic or acidic catalyst at a temperature of from 150 to 260° C. under a reduced pressure condition of not higher than 300 mmHg, (2) a distillation step of supplying the cleavage step product formed in the cleavage step in a vapor state to a distillation column and distilling at a temperature of from 130 to 200° C. under a reduced pressure condition of not higher than 300 mmHg, and (3) a reflux step of condensing the distillate from the distillation step, refluxing a part thereof to the distillation step at a reflux ratio of from 0.01 to 3, and discharging out the residue from the system.
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