Method of reducing impurities in a catalyst for producing terephthalic acid

Patent metadata

Field	Value
Publication number	US-11180439-B2
Application number	US-201816633935-A
Country	US
Kind code	B2
Filing date	Aug 9, 2018
Priority date	Aug 11, 2017
Publication date	Nov 23, 2021
Grant date	Nov 23, 2021

Abstract

A method of reducing impurities in a catalyst for the production of purified terephthalic acid includes forming purified terephthalic acid by hydrogenating crude terephthalic acid with a catalyst in a reactor; separating the purified terephthalic acid from the catalyst and reactivating the catalyst by washing with a caustic solution; and flushing the catalyst contaminated with impurities with a non-caustic liquid at a flushing temperature of greater than or equal to 50° C.

First claim

What is claimed is:

1. A method of reducing impurities in a catalyst for the production of purified terephthalic acid, comprising:
forming purified terephthalic acid by hydrogenating crude terephthalic acid with a catalyst comprising at least one Group VIII noble metal-containing component on a support in a reactor;
separating the purified terephthalic acid from the catalyst and reactivating the catalyst by washing with an alkaline solution comprising a hydroxide of sodium, potassium, or ammonium, a basic phase transfer catalyst, or a combination comprising at least one of the foregoing; and
flushing the catalyst with a non-alkaline liquid at a flushing temperature of about 50° C. to about 150° C. to remove impurities from the catalyst imparted by the alkaline solution.

2. The method of claim 1 , wherein the flushing temperature is about 75° C. to about 150° C.

3. The method of claim 1 , wherein the non-alkaline liquid comprises demineralized water.

4. The method of claim 1 , wherein the flushing of the catalyst contaminated with impurities comprises continuously flushing the catalyst contaminated with impurities or wherein flushing of the catalyst comprises batch wise flushing of the catalyst contaminated with impurities.

5. The method of claim 1 , wherein the alkaline solution comprises a hydroxide of sodium.

6. The method of claim 1 , wherein the impurities present in the catalyst comprise sodium.

7. The method of claim 6 , wherein the washing contaminates the catalyst with sodium, and wherein the flushing reduces sodium present in the catalyst to an amount of less than or equal to 1000 parts per million.

8. The method of claim 1 , wherein the washing contaminates the catalyst with impurities, and wherein the flushing reduces impurities present in the catalyst to an amount of less than 1000 parts per million.

9. The method of claim 1 , wherein the catalyst is present in a reactor bed of the reactor, and wherein the separating, washing, and flushing take place in the reactor.

10. The method of claim 9 , comprising continuously flushing the catalyst contaminated with impurities with less than or equal to 50 catalyst bed volumes of the non-alkaline liquid.

11. The method of claim 9 , comprising batch wise flushing the catalyst contaminated with impurities with the non-alkaline liquid, wherein the non-alkaline liquid comprises water, and with a ratio of water to catalyst equal to 50:1 with a soaked time of 40 minutes to 60 minutes.

12. The method of claim 9 , further comprising reusing the catalyst in the reactor for further formation of purified terephthalic acid.

13. A method of making a polyethylene terephthalate polymer, the method comprising:
reducing impurities in a catalyst according to the method of claim 1 ; and
polymerizing the purified terephthalic acid separated from the catalyst with ethylene glycol to make the polyethylene terephthalate polymer.

14. A method of reducing impurities in a catalyst for the production of purified terephthalic acid, comprising:
forming purified terephthalic acid by hydrogenating crude terephthalic acid with a catalyst comprising at least one Group VIII noble metal-containing component on a support in a reactor;
separating the purified terephthalic acid from the catalyst and reactivating the catalyst by washing with a solution comprising sodium hydroxide; and
flushing the catalyst continuously with demineralized water at a flushing temperature of about 50° C. to about 150° C. to remove sodium hydroxide from the catalyst imparted by the solution comprising sodium hydroxide.

15. The method of claim 14 , wherein the washing contaminates the catalyst with sodium, and wherein the flushing reduces a sodium content in the catalyst to an amount of less than or equal to 1000 parts per million.

16. The method of claim 14 , wherein the separating, washing, and flushing take place in the reactor, and wherein the sodium content in the flushed water drained from the reactor is less than or equal to 5 parts per million and the conductivity of the flushed water is less than or equal to 50 microSiemens per centimeter.

17. A method of reducing impurities in a catalyst for the production of purified terephthalic acid, comprising:
forming purified terephthalic acid by hydrogenating crude terephthalic acid with a catalyst comprising at least one Group VIII noble metal-containing component on a support in a reactor;
separating the catalyst from the purified terephthalic acid and reactivating the catalyst by washing with a solution comprising sodium hydroxide; and
flushing the catalyst with water at a flushing temperature of about 50° C. to about 150° C. to remove sodium hydroxide from the catalyst imparted by the solution comprising sodium hydroxide.

18. The method of claim 17 , comprising flushing the catalyst downstream of the purified terephthalic acid reactor.

19. The method of claim 18 , comprising flushing the catalyst in a rotary pressure filter, a rotary vacuum filter, or product transfer lines.

20. The method of claim 1 , wherein the flushing temperature is about 80° C. to about 125° C.

Assignees

• Sabic Global Technologies Bv

Inventors

• Hashmi Syed Azhar
• Nedumbamana Sankaran B
• Rasadiya Paresh Bhagvanbhai

Classifications

• B01J38/64

  using alkaline material; using salts · CPC title

• C07C51/64

  Separation; Purification; Stabilisation; Use of additives · CPC title

• C07C63/26 Primary

  1,4 - Benzenedicarboxylic acid · CPC title

• C07C51/487

  by treatment giving rise to chemical modification (by chemisorption C07C51/47) · CPC title

• C07C51/48 Primary

  by liquid-liquid treatment · CPC title