Chiyoda Corporation

Karou Shimogawara

Tsuneo Watanabe

Sachio Asaoka

Noriyuki Yoneda

Hiroaki Nishijima

Nobuo Moriya

Nobuhiro Onda

Kouji Sakashita

Tetsuo Maejima

Makoto Yasui

Akio Shindo

Ryuichi Inaba

Takashi Imazeki

Athumi Kukudome

High quality bisphenol A is produced from a neutral crystalline adduct of bisphenol A and phenol by fusing the adduct in an atmosphere having a maximum oxygen content of 0.005% by volume, followed by evaporation of liberated phenol. The crystalline adduct may be mixed with an aliphatic carboxylic acid before the fusion to reduce the coloring of the product. When an acidic crystalline adduct is used, the use of a strong alkali salt of an aliphatic carboxylic acid is suitably used. Interior surfaces of the apparatuses for carrying out the fusion and evaporation are desirably washed with an organic solvent to remove oxygen therefrom. The evaporation of phenol is suitably performed by two stage steam stripping wherein a used stripping gas obtained in the second stage is employed as a stripping gas in the first stage while steam is used as the stripping gas in the second stage.

Process for the production of bisphenol A

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Fujisawa, Japan

Karou Shimogawara