Process for the purification of monotertiarybutyl hydroquinone

• US 5,087,771 A
• Filed: 12/05/1990
• Issued: 02/11/1992
• Est. Priority Date: 12/05/1990
• Status: Expired due to Term

• Current Assignee: Eastman Chemical Company
• Original Assignee: Eastman Kodak Company
• Inventors: Hilderbrand, James R.
• Primary Examiner(s): LONE, WERREN
• Application Number:
  US07/622,453
• Time in Patent Office: 433 Days
• Field of Search: 568/753, 568/780, 568/749, 568/766
• US Class Current: 568/753
• CPC Class Codes: C07C 37/685 Processes comprising at least two steps in series
• CPC Class Codes: C07C 37/70 by physical treatment
• CPC Class Codes: C07C 37/72 by liquid-liquid treatment
• CPC Class Codes: C07C 37/84 by crystallisation
• CPC Class Codes: C07C 39/08 Dihydroxy benzenes; Alkylated derivatives thereof

Abstract

A process for producing food-grade tertiary-butyl hydroquinone from impure montertiary butyl hydroquinone is provided. Impure monotertiary butyl hydroquinone crystals are agitated at an elevated temperature while in contact with a non-polar solvent under conditions to extract the majority of the impurities followed by separating purified monotertiary butyl hydroquinone crystals from the solvent at a temperature above the crystallization point of the impurities.

Claims

1. A process for purifying monotertiarybutyl hydroquinone comprising:

(a) agitating a mixture of impure monotertiarybutyl hydroquinone crystals containing 2,5 ditertiarybutyl hydroquinone, assaying between about 90 and 99 weight percent monotertiarybutyl hydroquinone on a dry basis, and a non-polar solvent at a temperature of about 80°

C. to about 118°

C. under conditions of pressure such that a sufficient amount of solvent remains in the contacting vessel at the contacting temperature for a sufficient time to remove a majority of impurities from the monotertiarybutyl hydroquinone; and

(b) separating monotertiarybutyl hydroquinone crystals from the solvent at a temperature above the crystallization point of 2,5 ditertiarybutyl hydroquinone in the solvent, said crystals assaying 99.0 weight percent minimum monotertiarybutyl hydroquinone on a dry basis.

2. The process according to claim 1 wherein the non-polar solvent is also a non-aromatic solvent

3. The process according to claim 2 wherein said solvent is selected from n-heptane, octane, isooctane, cyclohexane, and naphtha.

4. The process according to claim 2 wherein step (a) is conducted at about atmospheric pressure and the non-polar, non-aromatic solvent is a relatively high boiling solvent such that the mixture in (a) has a boiling point between about 85°

and about 115°

C.

5. The process according to claim 1 wherein said monotertiarybutyl hydroquinone is in the form of water-wet crystals that have been prepared by reacting hydroquinone with either isobutylene, or tertbutyl alcohol in the presence of a strong acid catalyst assaying between about 95 and 99 weight percent monotertiarybutyl hydroquinone.

6. The process according to claim 1 wherein the amount of non-polar solvent used in Step (a) is between about 70 and about 95 weight percent based on the total weight of solvent and dry monotertiarybutyl hydroquinone.

7. The process according to claim 1 wherein the mixture in (a) contains about 2 to about 10 weight percent water based on the total.

8. The process according to claim 1 wherein the mixture in Step (a) also contains about 0.1 to about 0.5 wt. % of a water soluble reducing agent selected from the group consisting of ascorbic acid, erythorbic acid, sodium hydrosulfite, sodium erythorbate, and sulfur dioxide.

9. The process according to claim 1 wherein Step (a) is conducted at or below reflux conditions at a temperature between about 85°

and about 105°

C. for a time between about 15 minutes and about 2 hours.

10. The process according to claim 1 wherein Step (b) is conducted at a temperature of at least 50°

C.

11. The process according to claim 1 further comprising a cooling step between Step (a) and Step (b) wherein the mixture of Step (a) is cooled to a temperature between about 60°

and about 80°

C.

12. The process according to claim 1 further comprising:

(c) washing the separated purified monotertiarybutyl hydroquinone crystals with a polar solvent; and

(d) drying the washed monotertiarybutyl hydroquinone crystals.

13. The process according to claim 12 wherein said polar solvent is water.

14. A process for purifying monotertiarybutyl hydroquinone comprising:

(a) agitating a mixture of (1) impure water wet crystals of monotertiarybutyl hydroquinone containing 2,5 ditertiarybutyl hydroquinone, assaying between about 95 and 99 weight percent monotertiarybutyl hydroquinone on a dry basis, (2) non-polar, non-aromatic solvent, and (3) water soluble reducing agent selected from the group consisting of ascorbic acid, erythorbic acid, sodium hydrosulfite, sodium erythorbate, and sulfur dioxide at a temperature of about 80°

to about 118°

C. at about atmospheric pressure for at least about 15 minutes wherein the mixture has a boiling point in the range of about 85°

to about 115°

C.;

(b) cooling the mixture of (a) to no lower than 50°

C.;

(c) separating purified crystals of monotertiarybutyl hydroquinone from the solvent; and

(d) washing the purified crystals with a polar solvent.

15. A process for purifying monotertiarybutyl hydroquinone comprising:

(a) agitating a mixture of (1) impure water wet crystals of monotertiarybutyl hydroquinone containing 2,5 ditertiarybutyl hydroquinone, assaying between about 95 and 99 weight percent monotertiarybutyl hydroquinone on a dry basis, (2) naphtha present in a concentration between about 75 and about 85 weight percent based on the total, and (3) water soluble reducing agent selected from ascorbic acid and sodium hydrosulfite at a temperature between about 85° and

about 105°

C. at about atmospheric pressure for a time between about 15 minutes and 2 hours wherein the mixture has a boiling point in the range of about 85°

to 115°

C.;

(b) cooling the mixture of (a) to no lower than 50°

C.;

(c) separating purified crystals of monotertiarbutyl hydroquinone from the solvent; and

(d) washing the purified crystals with a polar solvent.