Selective dealkylation of 4-tertiary-alkyl-2,5-xylenol
AssigneeConoco Inc.
InventorJohn R. Dodd
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Abstract
A method is described for the selective dealkylation of 4-tertiary-alkyl-2,5-xylenol while it is admixed with 6-tertiary-alkyl-2,4-xylenol by contacting the mixture of alkylated xylenols with a polymer-bound sulfonic acid catalyst at temperatures of 60.degree. C. or less and pressures of from about 0.5 to 5 atmospheres. The method is useful in separating 2,4-/2,5-xylenol mixtures.
Claims9
An improved method for selectively dealkylating 4-t-alkyl-2,5-xylenol when in admixture with 6-t-alkyl-2,4-xylenol by contacting a mixture of the above components with a strongly acidic polymer-bound sulfonic acid catalyst, the improvement comprising carrying out the dealkylation at temperatures equal to or less than 60.degree. C. and pressures of from about 0.5 to about 5 atmospheres.
A method for the recovery of high purity 2,5-xylenol from admixture with 2,4-xylenol comprising
- (1) butylating the entire 2,4-xylenol/2,5-xylenol mixture with isobutylene at a temperature of from about 20.degree. C. to about 100.degree. C. and pressures of from about ambient to about 200 pounds per square inch gauge in the presence of an acid catalyst to form predominantly 4-t-butyl-2,5-xylenol and 6-t-butyl-2,4-xylenol,
- (2) fractionating the butylated mixture to remove any unbutylated xylenols and provide a mixture containing predominantly 4-t-butyl-2,5-xylenol and 6-t-butyl 2,4-xylenol.
- (3) selectively debutylating 4-t-butyl-2,5-xylenol while in admixture with 6-t-butyl-2,4-xylenol to afford a mixture containing predominantly 2,5-xylenol and 6-t-butyl-2,4-xylenol by
- (4) contacting the butylated mixture from (2) with a polymer-bound sulfonic acid catalyst at temperatures of 60.degree. C. or less and a pressure of from about 0.5 to about 5 atmospheres, and then
- (5) fractionating the resulting mixture to separate 2,5-xylenol from the other components in the debutylation mixture.
Dependencies are inferred from the claim text.