Process for purifying a bisphenol

• US 5,512,700 A
• Filed: 03/10/1995
• Issued: 04/30/1996
• Est. Priority Date: 03/15/1994
• Status: Expired due to Fees

• Current Assignee: Dow Deutschland Incorporated Zweigniederlassung Stade (Dow, Inc.)
• Original Assignee: Dow Deutschland Incorporated Zweigniederlassung Stade (Dow, Inc.)
• Inventors: Gressmann, Jochen, Kraehling, Karl, Patrascu, Emil
• Primary Examiner(s): LONE, WERREN
• Application Number:
  US08/401,513
• Time in Patent Office: 417 Days
• Field of Search: 568/722, 568/724, 568/727, 568/749, 568/753
• US Class Current: 568/724
• CPC Class Codes: C07C 37/685 Processes comprising at least two steps in series
• CPC Class Codes: C07C 37/84 by crystallisation
• CPC Class Codes: C07C 39/16 Bis-(hydroxyphenyl) alkanes; Tris-(hydroxyphenyl)alkanes

Abstract

A process for the purification of a crude bisphenol comprises the following steps:

(1) preparing a mixture comprising from about 35 to about 70% of a crude bisphenol and from about 65 to about 30% of water, by the total weight of bisphenol and water, without addition of a substantial amount of an organic solvent or an alkaline compound, at a pressure above atmospheric and a temperature above about 100° C.,

(2) crystallizing bisphenol at a pressure below atmospheric,

(3) separating crystalline bisphenol from the mother liquor,

(4) dividing at least a portion of the mother liquor into a bisphenol-rich oil phase and a water-rich phase,

(5) preparing a mixture comprising at least a portion of the bisphenol-rich oil phase, water and optionally an additional amount of crude bisphenol at a pressure above atmospheric and a temperature above about 100° C.,

(6) cooling the mixture and crystallizing bisphenol; and

(7) separating crystalline bisphenol from the mother liquor.

Claims

1. A process for the purification of a crude bisphenol which comprises the steps of:

(1) preparing a mixture comprising from about 35 to about 70 parts by weight of a crude bisphenol and from about 65 to about 30 parts by weight of water, without addition of a substantial amount of organic solvent or an alkaline compound, at a pressure above atmospheric and a temperature above about 100°

C.,

(2) crystallizing bisphenol at a pressure below atmospheric,

(3) separating crystalline bisphenol from the mother liquor,

(4) dividing at least a portion of the mother liquor into a bisphenol-rich oil phase and a water-rich phase,

(5) preparing a mixture comprising at least a portion of the bisphenol-rich oil phase and water at a pressure above atmospheric and a temperature above about 100°

C.,

(6) cooling the mixture and crystallizing bisphenol; and

(7) separating crystalline bisphenol from the mother liquor.

2. The process of claim 1 wherein an additional amount of crude bisphenol is included in the mixture prepared in step (5).

3. The process of claim 2 wherein the mixture prepared in step (5) comprises from about 25 to about 90 parts by weight of the bisphenol-rich oil phase and from about 75 to about 10 parts by weight of additional crude bisphenol.

4. The process of claim 3 wherein the mixture prepared in step (5) comprises from about 65 to about 200 parts by weight of water.

5. The process of claim 1 wherein the pressure in step (1) is from about 1.5 to about 5 bar.

6. The process of claim 2 wherein the pressure in step (1) is from about 1.5 to about 5 bar.

7. The process of claim 4 wherein the pressure in step (1) is from about 1.5 to about 5 bar.

8. The process of claim 1 wherein the temperature in step (1) is from about 110°

C. to about 150°

C.

9. The process of claim 4 wherein the temperature in step (1) is from about 110°

C. to about 150°

C.

10. The process of claim 1 wherein in step (2) the mixture is cooled to a temperature of from about 80°

C. to about 100°

C.

11. The process of claim 4 wherein in step (2) the mixture is cooled to a temperature of from about 80°

C. to about 100°

C.

12. The process of claim 1 wherein the pressure in step (5) is from about 2.1 to about 4.5 bar.

13. The process of claim 2 wherein the pressure in step (5) is from about 2.1 to about 4.5 bar.

14. The process of claim 4 wherein the pressure in step (5) is from about 2.1 to about 4.5 bar.

15. The process of claim 1 wherein in step (6) the mixture is cooled to a temperature of from about 70°

C. to about 98°

C.

16. The process of claim 4 wherein in step (6) the mixture is cooled to a temperature of from about 70°

C. to about 98°

C.

17. The process of claim 1 wherein in step (6) the pressure is decreased to an absolute pressure of from about 420 to about 920 mbar.

18. The process of claim 4 wherein in step (6) the pressure is decreased to an absolute pressure of from about 420 to about 920 mbar.

19. The process of claim 1 wherein separated crystalline bisphenol is washed with water at a temperature of from about 70°

C. to about 100°

C.

20. The process of claim 1 wherein separated crystalline bisphenol is washed with water at a temperature of from about 70°

to about 100°

C.