GB849965A - Preparation of bisphenols - Google Patents

Abstract

Bisphenols are produced by reacting a ketone having at least one methyl group in the alphaposition to the carbonyl group, or an alicyclic ketone, with a molar excess of a phenol which has a reactive hydrogen atom in the paraposition to the phenolic hydroxyl group, the reaction being carried out, at a temperature between 40 DEG and 150 DEG C., in the presence of a substantially insoluble and water-free cationexchange resin having strong acid groups, such as a styrene-divinyl benzene sulphonated resin, a sulphonated cross-linked styrene polymer, a phenol-formaldehyde sulphonated resin, or a benzene-formaldehyde sulphonated resin. The resin structure is preferably in the form of microspheres or beads, or it can be made porous. If the resin is initially in the salt-form, it is treated with sulphuric acid, and then washed with water. The water-wet resin is then dried, e.g., by azeotropic distillation of the water with phenol; and it is then ready for use in the phenol-ketone condensation. The following phenols may be used in the reaction:-phenol, 0- and mcresol, 2, 6-dimethylphenol, 1, 3, 5-xylenol, tetramethylphenol, 2-methyl-6-tert-butyl phenol, 0- and mchlorophenol, and 2, 6-dichlorophenol. The following ketones may be used in the reaction:-acetone, methyl ethyl ketone, methyl propyl ketone, acetophenone, methyl vinyl ketone, and cyclohexanone. In Example 1, a sulphonated styrene-divinylbenzene polymer is treated with sulphuric acid, washed with water, and then heated with phenol under a pressure of 20 mm. Hg. whereby the water distils off with some of the phenol. The phenol-wet catalyst is packed into a glass-column 100 inches long, and a mixture of phenol and acetone, in the molar ratio of 10:1, is pumped through the column while it is maintained at a temperature of 75 DEG C. The contacttime between the resin and the phenol/acetone mixture is about 1 hour. The effluent is cooled to 27 DEG C. to precipitate some of the phenol-2, 2-bis (4-hydroxyphenyl) propane complex along with the phenol. The precipitate is filtered off, and washed with successive portions of water to remove phenol. The dried filter-cake is finally distilled under 0,2 mm. Hg. pressure, yielding high-purity 2, 2-bis (4-hydroxyphenyl) propane. Additional quantities of this product are obtained by working-up the filtrate from the precipitated complex and also the phenolic wash water. In Example 7, phenol is reacted with acetophenone. In Example 8, o-cresol is reacted with acetone. In Example 9, phenol is reacted with acetone in the presence of sulphonated poly-p-xylylene. In Example 10, cyclohexanone is reacted with o-chlorophenol to obtain 1, 1-bis (4-hydroxy-3-chlorophenyl)-cyclohexane.