To recover bis-phenol A from compositions containing reaction residue of a dihydric phenol, particularly bis-phenol A units.
A bis-phenol A-containing polymer is roughly crushed and the crushed granules are treated with an organic swelling solvent which is compatible to water such as an alcohol or other solvent and can be readily distilled off from the aqueous solution for a time enough to swell the crushed granules. Then, the swollen crushed granules are brought into contact with an aqueous ammonia which can selectively cleave the ester bonds of the bis-phenol A residual units at a temperature of ≥25°C to form the liquid phase and the solid phase. The liquid phase is separated from the solid phase, ammonia and the organic swelling solvent are distilled out of the liquid phase to obtain an aqueous solution containing dissolved urea, partially precipitated bis-phenol A. A sufficient amount of water is added to the solution to precipitate bis-phenol A to form the liquid phase the solid phase. Finally, the bis phenol A of the solid phase is recovered and dried.
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DE HEER JOS
HOOGLAND GABRIE
NANGUNERI SRIKANTH
DE WIT GERT
