Patent ID: 7598424
Filing Date: 2009-10-06
Classification: C07C

Abstract:
1. A process of producing bisphenol A comprising: (A) a step of producing a phenolic solution containing bisphenol A by reacting phenol with acetone, (B) a crystallization step of cooling the obtained phenolic solution containing bisphenol A in a crystallization device and continuously forming a slurry containing adduct crystals comprising phenol and bisphenol A, (C) a solid-liquid separation step of separating the adduct crystals from the slurry, and (D) a step of producing bisphenol A by removing phenol from the adduct crystals, wherein, in the crystallization step, (a) the fed solution of bisphenol A in phenol is cooled at temperatures of at least two steps to form a slurry containing adduct crystals, (b) at least two crystallization stages having different cooling temperatures are provided, and (c) when the solid fraction of the slurry is A [% by weight]in the final crystallization stage prior to transporting the slurry into the solid-liquid separation step and is B [% by weight] in the crystallization stage in which crystals are first formed, the value of B/A is kept at 0.7 or less.