Process for the purification of bisphenol A
AssigneeShell Oil Company
InventorArien Kwantes
Life of this patent
Estimating the term…
Abstract
Crude 2,2-bis(4-hydroxyphenyl)propane containing impurities such as 2-(2-hydroxyphenyl)-2-(4-hydroxyphenyl)propane is purified by first dissolving the crude material in a polyhydroxy solvent then adding water and an ether having a boiling point less than 110.degree.C whereby the ether extracts the 2,2-bis(4-hydroxyphenyl)propane. The ether-2,2-bis(4-hydroxyphenyl)propane extract is then distilled in the presence of toluene wherein the toluene-2,2-bis(4-hydroxyphenyl)propane bottoms product is separated and cooled to form a purified 2,2-bis(4-hydroxyphenyl)propane precipitate which is subsequently recovered.
Claims5
A process for the purification of a crude 2,2-bis(4-hydroxyphenyl)propane mixture prepared by condensing phenol with acetone or 2,2-dimethyl-1,3-dioxolane, said mixture being substantially free of phenol, which process comprises:
- a. dissolving the crude 2,2-bis(4-hydroxyphenyl)propane and impurities in a polyhydroxy solvent selected from alkane diols and alkane triols;
- b. contacting the polyhydroxy solvent-crude 2,2-bis(4-hydroxyphenyl)propane solution with water and an ether selected from the group consisting of diethyl ether, ethyl-n-propyl ether, ethylisopropyl ether, methyl-tert-butyl ether, di-n-propyl ether, diisopropyl ether and furan, wherein said ether extracts the 2,2-bis(4-hydroxyphenyl)propane;
- c. separating the ether-2,2-bis(4-hydroxyphenyl)propane extract;
- d. distilling the ether-2,2-bis(4-hydroxyphenyl)propane extract in a column and in the presence of toluene and recovering as bottoms product a toluene-2,2-bis(4-hydroxyphenyl)propane solution;
- e. cooling the toluene-2,2-bis(4-hydroxyphenyl)propane bottoms product to form a purified 2,2-bis(4-hydroxyphenyl)propane precipitate;
- and
- f. recovering the purified 2,2-bis(4-hydroxyphenyl)propane.
Dependencies are inferred from the claim text.