PURPOSE: To produce bisphenol A useful as a raw material for polycarbonate resins, etc., used in optical disks by filtering a melt (solution) of bisphenol A through a specific filter and removing contained fine particles at a high efficiency.
CONSTITUTION: A melt of (A1) bisphenol A or a solution prepared by dissolving the compound (A1) in (A2) phenol is filtered through (B) a fluorine-based membrane filter (e.g. the one having ≤1.0μm filtration accuracy) to provide bisphenol A. For example, the compound (A2) is reacted with acetone by using an acidic catalyst to afford a reactional mixture and water and the catalyst are then removed therefrom. The concentration of the compound (A1) is regulated and the resultant mixture is subsequently cooled to deposit an adduct crystal (C1) of the compounds (A1) to (A2). The deposited crystal (C1) is further thermally melted and filtered through the filter (B). The compound (A2) is subsequently removed to provide the molten compound (A1), which is then cooled and granulated. Otherwise, the adduct crystal (C1) is thermally melted to remove the compound (A2) and the molten compound (A1) is obtained, filtered through the filter (B), then cooled and granulated to afford the compound (A1).
SATO NORIO
MIURA MIYUKI
