Methods for purifying p,p-bisphenol-A

• US 7,371,902 B2
• Filed: 09/29/2004
• Issued: 05/13/2008
• Est. Priority Date: 09/29/2004
• Status: Expired due to Fees

• Current Assignee: SABIC Global Technologies BV (Government of Saudi Arabia)
• Original Assignee: General Electric Company
• Inventors: Bhotla, Venkata Rama Narayanan Ganapathy, Murukutla, Dwijaraja Mouli, Bastian, Hyacinth Mary, Kumar, Ramachandran, Ramamurthy, Kumar Krishna, Sathyanarayana, Gururaj, Shafer, Sheldon Jay, Ravi, Gomatam Raghavan
• Primary Examiner(s): PUTTLITZ, KARL J
• Application Number:
  US10/953,132
• Publication Number:
  US 20060069292A1
• Time in Patent Office: 1,322 Days
• Field of Search: 568/724, 568/728
• US Class Current: 568/724
• CPC Class Codes: C07C 37/74 by distillation
• CPC Class Codes: C07C 39/16 Bis-(hydroxyphenyl) alkanes; Tris-(hydroxyphenyl)alkanes

Abstract

Methods for purifying a p,p-bisphenol A generally include distilling a feed stream comprising p,p-BPA in a distillation column at a pressure less than or equal to 20 millibars. The distillation column separates the bisphenol feed stream to produce a light fraction, an intermediate fraction and a heavy fraction. The intermediate fraction comprising the purified bisphenol contains lesser impurities that the p,p-BPA in the feed stream. In one embodiment, the intermediate stream is recovered using a side-draw. The side-draw is located between a first zone and a third zone in the distillation column.

Claims

1. A method for purifying p,p-bisphenol A, said method comprising:

distilling a feedstream comprising p,p-bisphenol A in a distillation column at a pressure less than or equal to 20 millibars;

producing a light fraction, an intermediate fraction, and a heavy fraction from the distillation column;

feeding the heavy fraction to a second reactor and isomerizing impurities in the heavy fraction to produce additional p,p-bisphenol A;

feeding a portion of the light fraction to a first reactor and purging a remaining portion of the light fraction in a third reactor, wherein feeding the portion to the first reactor converts impurities in the light fraction to produce additional p,p-bisphenol A, and wherein feeding the remaining portion to the third reactor removes impurities from the remaining portion; and

recovering the intermediate fraction as a side draw of the distillation column, wherein the p,p-bisphenol A in the intermediate fraction contains less impurities than the p,p-bisphenol A in the feedstream.

2. The method of claim 1, wherein said feedstream comprises greater than or equal to 80% p,p-bisphenol A.

3. The method of claim 1, wherein the light fraction is a vapor, a liquid or a vapor-liquid.

4. The method of claim 1, wherein the intermediate and heavy fractions are liquids.

5. The method of claim 1, wherein the first reactor comprises an acid catalyst.

6. The method of claim 1, further comprising introducing phenol into the first reactor.

7. The method of claim 1, further comprising feeding a feedstream containing the additional p,p-bisphenol A produced in the first reactor to the distillation column.

8. The method of claim 1, wherein the third reactor produces an effluent comprising phenol or phenol and isopropenyl phenol.

9. The method of claim 1, wherein the second reactor comprises an acid catalyst.

10. The method of claim 1, further comprising simultaneously feeding a solvent into the second reactor.

11. The method of claim 1, further comprising introducing phenol into the second reactor.

12. The method of claim 1, further comprising feeding a feedstream containing the additional p,p-bisphenol A produced in the second reactor to the distillation column.

13. The method of claim 1, wherein the distillation column comprises 4 to 30 theoretical stages.

14. A method for purifying a feedstream comprising p,p-bisphenol A, comprising:

flowing the feedstream comprising p,p-bisphenol A into a distillation column, wherein the distillation column comprises a first zone, a third zone, and a second zone intermediate the first and third zones;

wherein flowing the feedstream comprises introducing the feedstream into the second zone;

distilling the feedstream into three fractions, wherein a light fraction is produced from the first zone, an intermediate fraction is produced from the second zone and a heavy fraction is produced from the third zone, wherein the intermediate fraction is withdrawn from the distillation column as a side draw and comprises p,p-bisphenol A at a purity greater than 90% and at a purity greater than the p,p-bisphenol A in the feedstream.

15. The method of claim 14, further comprising:

flowing the light fraction to a first reactor, wherein the light fraction comprises o,p-bisphenol A and/or isopropenyl phenol; and

converting the o,p-bisphenol A to form additional p,p-bisphenol A, and/or reacting the isopropenyl phenol with phenol to form the additional p,p-bisphenol A.

16. The method of claim 15, further comprising:

feeding the additional p,p, bisphenol A to the distillation column.

17. The method of claim 14, further comprising:

flowing the heavy fraction to a second reactor; and

isomerizing o,p-bisphenol A, and/or 2,4-bis[2-(4-hydroxyphenyl)propyl]phenol, and/or 4-[1-methyl-1-{2,2,4-trimethyl-4-(p-hydroxyphenyl)-chroman-6-yl}-ethyl]-phenol to form additional p,p-bisphenol A.

18. The method of claim 17, further comprising feeding the additional p,p-bisphenol A to the distillation column.

19. The method of claim 17, further comprising diluting the heavy fraction with a solvent.

20. The method of claim 14, wherein the distillation column is at a pressure less than or equal to 20 millibars, the first zone is at a temperature of 150 to 230°

C., the second zone is at a temperature of 210 to 230°

C., and the third zone is at a temperature of 200 to 300°

C.