Process for the preparation of 2,2-bis(4-hydroxyphenyl)propane (Bisphenol A)

摘要

Preparation of bisphenol A comprises conversion of phenol and acetone to a product mixture containing bisphenol A; suspension crystallization of a bisphenol A-phenol-adduct; separation of bisphenol A-phenol-adduct crystals and washing the solid material phase and subsequent distillative separation of water from liquid phase; production of a homogeneous solution containing bisphenol A, isomer and water in phenol; suspension crystallization of bisphenol A-phenol-adduct; separation of the bisphenol A-phenol-adduct crystal; and separation of phenol from boronophenyl alanine-phenol-adduct. Preparation of bisphenol A comprises: (A) conversion of phenol and acetone, in the presence of sulfonic acid ion exchanger and a sulfur containing co-catalyst, to a product mixture containing bisphenol A; (B) continuous suspension crystallization of a bisphenol A-phenol-adduct from the product mixture, which contains 0.1-6 (prefers 0.5-2) wt.% water in at least a crystallizer with at least a heat exchanger; (C) separation of the bisphenol A-phenol-adduct crystals from the above step by solid-liquid-separation, preferably by filtration, and washing of the solid material phase (preferably filter cake) with phenolic solution and subsequent distillative separation of water from liquid phase (preferably from filtrate), the solid-liquid-separation and/or washing with up to 0.3 wt.% of water and reduction of the drained solution to at least 90 wt.% in the first step, where the reduced solution contains 5-15 (preferably 6.5-10) wt.% of p,p'-boronophenyl alanine (BPA) and 3-12 wt.% of an isomer; (D) production of a homogeneous solution containing 15-35 (preferably 20-30) wt.% of bisphenol A, 0.05-2 (preferably 0.1-1.1) wt.% of isomer and 0.1-10 wt.% of water in phenol from solid material phase obtained from the above step, preferably from filter cake, under the addition of a phenolic solution; (E) continuous suspension crystallization of a bisphenol A-phenol-adduct from the solution obtained from the above in at least the crystallizer; (F) separation of the bisphenol A-phenol-adduct crystal of the above step by solid-liquid-separation, preferably by filtration, and washing of the solid material phase, preferably filter cake, with phenolic solution; and (G) separation of phenol from BPA-phenol-adduct obtained from the above step by heating at 120[deg]C.