Patent ID: 6906227
Filing Date: 2005-06-14
Classification: C07C

Abstract:
1. A process for separating and purifying adducts of bis(4-hydroxyaryl)alkanes and aromatic hydroxy compounds obtained during production by acid-catalyzed reaction of aromatic hydroxy compounds with ketones, which process is characterized in that the adduct crystals formed in the process are separated from the mother liquor after crystallization out of the suspension by continuous filtration in a revolving vacuum drum filter containing a plurality of filter cells and then washed, and the washing liquid is drawn off, wherein the vacuum drum filter comprises a rotary filter housing and as filter cells a cake-forming zone, a washing zone, a drying suction zone, an aeration zone, a cake removal zone and a cloth rinsing zone, the vacuum applied in the cake-forming zone is 5 to 500 mbar, the vacuum applied in the washing zone is 5 to 300 mbar, the vacuum applied in the drying suction zone is 5 to 500 mbar, filter cake rinsing is performed in the washing zone using pure phenol at temperatures of 45 to 70° C. and using a rinsing agent quantity of 50 to 150 % relative to the quantity of filter cake, the filter cloth comprises a phenol- and heat-resistant filter cloth with air permeability of 300 to 1500 l/dm 2 /min, and cloth rinsing is performed at temperatures of 70 to 85° C.