Substantially pure spirobiindane bisphenols and method for their preparation
AssigneeGeneral Electric Company
InventorsGary R. Faler, Jerry C. Lynch
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Abstract
Spirobiindane bisphenols of high purity, suitable for conversion to high molecular weight polycarbonates, are prepared by reacting a bisphenol or 4-isopropenylphenol with a metal halide Lewis acid or an alkanesulfonic acid, followed by removing impurities including phenols, 1-(4-hydroxyphenyl)indanols and the like. A step of purification by precipitation with water from a methanol-methylene chloride solution is included.
Claims20
A method for preparing a substantially pure spirobiindane bisphenol of the formula ##STR6## wherein each R is independently C.sub.1-4 primary or secondary alkyl or halo and n is from 0 to 3, which comprises the steps of:
- (A) reacting at least one of bisphenols of the formula ##STR7## and isopropenylphenols of the formula ##STR8## by contact at a temperature in the range of about 100.degree.-200.degree. C. with an acidic catalyst selected from the group consisting of alkanesulfonic acids and polyvalent metal halides which are strong Lewis acids, thereby producing a crude spirobiindane bisphenol;
- (B) removing a major proportion of the by-products including phenols of the formula ##STR9## and 1-(4-hydroxphenyl)indanols of the formula ##STR10## from the crude spirobiindane bisphenol;
- and (C) further purifying the product of step B by dissolution in a mixture of methanol and methylene chloride followed by precipitation by addition of water.
Substantially pure 6,6'-dihydroxy-3,3,3',3'-tetramethyl-1,1'-spirobiindane having an absorbance at 350 nanometers of at most 0.06, as measured on a solution of 1 gram thereof in 100 ml. of spectroscopic grade methanol, using a path length of 10 cm.
Dependencies are inferred from the claim text.