| abstract |
Upon isomerizing bis(hydroxyphenyl) propanes other than bisphenol A (2,2-bis(4-hydroxyphenyl) propane) into bisphenol A by contacting a liquid containing bis(hydroxyphenyl) propanes to a strongly acidic cation-exchange resin, the water concentration of the liquid containing bis(hydroxyphenyl) propanes is regulated at 0.2 to 0.9% by mass. Thereby, the operating life of the isomerization catalyst used in the method for producing bisphenol A including an isomerization step can be extended, and bisphenol A can be produced efficiently. In addition, the amount of the catalyst disposed can be reduced. |