Emission control during catalyst regeneration

Patent metadata

Field	Value
Publication number	US-11065611-B2
Application number	US-201716339430-A
Country	US
Kind code	B2
Filing date	Oct 5, 2017
Priority date	Oct 5, 2016
Publication date	Jul 20, 2021
Grant date	Jul 20, 2021

Abstract

Catalyst regeneration processes that include measures for controlling emissions generated during the regeneration are described. The present invention further relates to catalytic processes for producing various chlorinated aromatic compounds that include provisions for controlling emissions during catalyst regeneration.

First claim

What is claimed is:

1. A process for regeneration of a heterogeneous process catalyst comprising a chlorinated aromatic compound adsorbed thereon, the process comprising:
desorbing at least a portion of the chlorinated aromatic compound from the heterogeneous process catalyst at a temperature no greater than about 350° C. prior to the step of heating the heterogeneous process catalyst at the temperature of from about 400° C. to about 1000° C. in the presence of oxygen to pre-clean the heterogeneous process catalyst;
heating the heterogeneous process catalyst having at least a portion of the chlorinated aromatic compound desorbed therefrom at a temperature of from about 400° C. to about 1000° C. in the presence of oxygen to remove at least a portion of the chlorinated aromatic compound from the heterogeneous process catalyst and produce a regenerated heterogeneous process catalyst and a regeneration effluent; and
contacting the regeneration effluent with an oxidation catalyst comprising at least one metal oxide selected from the group consisting of vanadium oxide, chromium oxide, manganese oxide, and mixtures thereof to form an oxidation effluent comprising carbon dioxide, water, and hydrochloric acid,
wherein the heterogeneous process catalyst comprises a zeolite.

2. The process of claim 1 wherein the at least one metal oxide comprises chromium oxide.

3. The process of claim 1 wherein the at least one metal oxide comprises vanadium oxide.

4. The process of claim 1 wherein the oxidation catalyst comprises the at least one metal oxide on a support.

5. The process of claim 4 wherein the support of the oxidation catalyst comprises at least one material selected from the group consisting of alumina, titania, silica, zirconia, carbon, zeolite, and combinations thereof.

6. The process of claim 4 wherein the support of the oxidation catalyst comprises titania.

7. The process of claim 1 wherein the oxidation catalyst is mixed with the heterogeneous process catalyst.

8. A process for regeneration of a heterogeneous process catalyst comprising a chlorinated aromatic compound adsorbed thereon, the process comprising:
heating the heterogeneous process catalyst at a temperature of from about 400° C. to about 1000° C. in the presence of oxygen to remove at least a portion of the chlorinated aromatic compound from the heterogeneous process catalyst and produce a regenerated heterogeneous process catalyst and a regeneration effluent; and
contacting the regeneration effluent with an oxidation catalyst comprising at least one metal oxide selected from the group consisting of vanadium oxide, chromium oxide, manganese oxide, and mixtures thereof to form an oxidation effluent comprising carbon dioxide, water, and hydrochloric acid,
wherein the oxidation catalyst is supported on the heterogeneous process catalyst and
wherein the heterogeneous process catalyst comprises a zeolite.

9. The process of claim 1 wherein a first stage comprises the heterogeneous process catalyst and a second stage comprises the oxidation catalyst comprising the at least one metal oxide and wherein the second stage is downstream of the first stage.

10. The process of claim 1 wherein desorbing at least a portion of the chlorinated aromatic compound from the heterogeneous process catalyst comprises applying vacuum to the heterogeneous process catalyst.

11. The process of claim 1 wherein desorbing at least a portion of the chlorinated aromatic compound from the heterogeneous process catalyst comprises
contacting the heterogeneous process catalyst with steam.

12. The process of claim 11 wherein the temperature of the steam is no greater than about 300° C.

13. The process of claim 8 wherein the at least one metal oxide comprises vanadium oxide.

14. The process of claim 1 wherein desorbing at least a portion of the chlorinated aromatic compound from the heterogeneous process catalyst is conducted in a non-oxidative atmosphere.

15. The process of claim 1 further comprising recycling at least a portion of the desorbed chlorinated aromatic compound to an isomerization reaction zone.

16. The process of claim 1 wherein the chlorinated aromatic compound comprises at least one compound selected from the group consisting of 2,3,4-trichlorophenol; 2,3,5-trichlorophenol; 2,3,6-trichlorophenol; 2,4,5-trichlorophenol; 2,4,6-trichlorophenol; 3,4,5-trichlorophenol; 2,3-dichlorophenol; 2,4-dichlorophenol; 2,5-dichlorophenol; 2,6-dichlorophenol; 3,4-dichlorophenol; 3,5-dichlorophenol; 2-chlorophenol; 3-chlorophenol; 4-chlorophenol; 1,2,3-trichlorobenzene; 1,2,4-trichlorobenzene; 1,3,5-trichlorobenzene; 1,2-dichlorobenzene; 1,3-dichlorobenzene; 1,4-dichlorobenzene; and oxidation and chlorination products thereof; and mixtures thereof.

17. A process for producing 2,5-dichlorophenol, the process comprising:
contacting a feed comprising 2,4-dichlorophenol with an isomerization catalyst comprising a zeolite in a reactor system comprising an isomerization zone to form a reaction product comprising 2,5-dichlorophenol, wherein the reactor system further comprises an oxidation catalyst comprising at least one metal oxide selected from the group consisting of vanadium oxide, chromium oxide, manganese oxide, and mixtures thereof; and
regenerating the isomerization catalyst according to the process of claim 1 , wherein the isomerization catalyst is the heterogeneous process catalyst comprising a chlorinated aromatic compound adsorbed thereon.

18. A process for producing 2,5-dichlorophenol, the process comprising:
contacting a feed comprising 2,4-dichlorophenol with an isomerization catalyst comprising a zeolite in a reactor system comprising an isomerization zone to form a reaction product comprising 2,5-dichlorophenol, wherein the reactor system further comprises an oxidation catalyst comprising at least one metal oxide selected from the group consisting of vanadium oxide, chromium oxide, manganese oxide, and mixtures thereof; and
regenerating the isomerization catalyst according to the process of claim 8 , wherein the isomerization catalyst is the heterogeneous process catalyst comprising a chlorinated aromatic compound adsorbed thereon.

19. A process for producing 2,5-dichlorophenol, the process comprising:
contacting a feed comprising 1,4-dichlorobenzene with an oxidizing agent in the presence of a hydroxylation catalyst comprising a zeolite in a reactor system comprising a hydroxylation zone to form a reaction product comprising 2,5-dichlorophenol, wherein the reactor system further comprises an oxidation catalyst comprising at least one metal oxide selected from the group consisting of vanadium oxide, chromium oxide, manganese oxide, and mixtures thereof; and
regenerating the hydroxylation catalyst according to the process of claim 1 , wherein the hydroxylation catalyst is the heterogeneous process catalyst comprising a chlorinated aromatic compound adsorbed thereon.

20. A process for producing 2,5-dichlorophenol, the process comprising:
contacting a feed comprising 1,4-dichlorobenzene with an oxidizing agent in the presence of a hydroxylation catalyst comprising a zeolite in a reactor system comprising a hydroxylation zone to form a reaction product comprising 2,5-dichlorophenol, wherein the reactor system further comprises an oxidation catalyst comprising at least one metal oxide selected from the group consisting of vanadium oxide, chromium oxide, manganese oxide, and mixtures thereof; and
regenerating the hydroxylation catalyst according to the process of claim 8

Assignees

• Monsanto Technology Llc

Inventors

• Wan Kam-To

Classifications

• C07C37/002 Primary

  by transformation of a functional group, e.g. oxo, carboxyl · CPC title

• B01J38/12

  Treating with free oxygen-containing gas · CPC title

• B01J38/02 Primary

  Heat treatment · CPC title

• B01J23/92

  of catalysts comprising metals, oxides or hydroxides provided for in groups B01J23/02 - B01J23/36 · CPC title

• Y02P20/584

  Recycling of catalysts · CPC title