PURPOSE: To obtain a bisphenol A reduced in thermal coloration and excellent in thermal stability.
CONSTITUTION: Bisphenol A containing impurities is subjected to a thermal treatment in the presence or absence of phenol in an atmosphere not containing oxygen gas at 185-220°C for 5-60 min, mixed with phenol when the phenol is short, dissolved in the phenol, and subsequently cooled to deposit the crystals of the bisphenol A-phenol adduct. The adduct is separated and then subjected to the separation and removal of the phenol from the adduct to produce the bisphenol A improved in thermal stability. Thus, the bisphenol A reduced in thermal coloration and excel lent in thermal stability can be obtained. Since having an excellent color tone, the bisphenol A can advantageously be used as a raw material for the production of polycarbonate resins, etc., which requires severe qualities on color tones.
SAKURA KATSUHIKO
MATSUI YOSHIAKI
MARUYAMA TOSHIKAZU
MORIYA NOBUO
SUDA NOBUYUKI
SHIMODA KEIJI
NOMURA MAKOTO
CHIYODA CHEM ENG CONSTRUCT CO