Method for producing vinyl acetate monomer from ethane or ethylene oxidation

Abstract

Methods for the catalytic production of vinyl acetate monomer from ethane, ethylene or an ethane/ethylene mixture using a first catalyst containing MoVNbPd, MoVLaPdNbX (where X is Al, Ga, Ge or Si) or MoVNbX (where X is P, B, Hf, Te, As or mixtures thereof) in the first step of oxidation and using a conventional VAM catalyst for the second step. The method produces high yields to acetic acid and vinyl acetate without the coproduction of carbon monoxide. Further-more, the ethylene and acetic acid produced in the first step may be utilized in the second step for VAM production

1. A process for the production of vinyl acetate monomer comprising the steps of: (1) contacting a gaseous feed mixture of ethane or ethylene or ethane/ethylene, steam and a molecular oxygen containing gas in the presence of a first catalyst active for oxidation of ethane, ethylene or ethane/ethylene to produce a selective stream of acetic acid, ethylene, carbon dioxide and water and (2) converting a second feed mixture comprising ethylene, acetic acid and oxygen to vinyl acetate monomer in the presence of a second catalyst active for the production of vinyl acetate, wherein said process does not include an intermediate separation step to remove the CO between the two reaction steps. 
     
     
       2. The process of claim  1  3, wherein said process produces no carbon monoxide. 
     
     
       3. The process of  claim 2 , A process for the production of vinyl acetate monomer comprising the steps of:
 (1) contacting a gaseous feed mixture of ethane or ethylene or ethane/ethylene, steam and a molecular oxygen containing gas in the presence of a first catalyst active for oxidation of ethane, ethylene or ethane/ethylene to produce a selective stream of acetic acid, ethylene, carbon dioxide and water, wherein the first oxidation catalyst is selected from the following catalyst compositions:
 a) a catalyst composition comprising consisting of the elements Mo, V, Nb, and Pd, in the form of oxides, in the ratio Mo a V b Nb c Pd d  wherein:
 a is 1 to 5; 
 b is 0 to 0.5; 
 c is 0.01 to 0.5; and 
 d is >0 to 0.2; 
 
 b) a catalyst composition comprising consisting of the elements Mo, V, Pd, Nb, La and X, in the form of oxides, wherein X is Al, Ga, Si or Ge, in the ratio Mo a V b La c Pd d Nb e X f  wherein:
 a is 1; 
 b is 0.01 to 0.9; 
 c is >0 to 0.2; 
 d is >0 to 0.2; 
 e is >0 to 0.2; and 
 f is >0 to 0.3; and 
 
 c) a catalyst composition comprising consisting of the elements Mo, V, Nb and X which is selected from P, B, Hf, Te, As or mixtures thereof in the form of an oxide, in the following ratio Mo a V b Nb c X d  wherein:
 a is 1 to S 5; 
 b is >0 to 0.1; 
 c is 0.01 to 0.5; 
 d is >0 to 0.1; and 
 
 
 (2) converting a second feed mixture comprising ethylene, acetic acid, and oxygen to vinyl acetate monomer in the presence of a second catalyst active for the production of vinyl acetate, wherein said process does not include an intermediate separation step to remove CO between the production of the selective stream and the converting of the second feed mixture, wherein at least a portion of the ethylene, acetic acid, and oxygen in the second feed mixture are from the selective stream. 
 
     
     
       4. The process of  claim 3 , wherein said first catalyst consists essentially of catalyst composition (a), catalyst composition (b), catalyst composition (c) or mixtures thereof. 
     
     
       5. The process of  claim 2 , wherein said first catalyst and second catalyst are in the form of a fixed or fluidized bed or a solid moving bed reactor. 
     
     
       6. The process of  claim 2 , wherein said feed mixture is fed into a second reaction zone. 
     
     
       7. The process of  claim 6 , wherein the second feed mixture for the second step comprises ethylene, acetic acid, CO 2  and oxygen. 
     
     
       8. The process of  claim 2 , wherein said feed mixture comprises molecular oxygen ranging from 0.1 to 25% by volume of the feed mixture. 
     
     
       9. The process of  claim 2 , wherein said feed mixture is diluted with N 2  in an amount ranging from 5 to 90% by volume. 
     
     
       10. The process of  claim 2 , wherein said feed mixture is diluted with steam in an amount ranging from 0 to 40% by volume. 
     
     
       11. The process of  claim 2 , wherein said feed mixture comprises from 1% to 95% by volume of ethane, ethylene or mixtures thereof. 
     
     
       12. The process of  claim 2 , wherein first step oxidation is achieved at a temperature of from 150 to 450° C., under a pressure of from 15 to 600 psi, and with a contact time between reaction mixture and the catalyst of from 0.1 to 60 seconds. 
     
     
       13. The process of  claim 2 , wherein said contacting comprises reacting ethane or ethane/ethylene with steam and oxygen or a compound capable of providing oxygen in the presence of said first catalyst in a first reaction zone to form a first product mixture comprising ethylene, oxygen, steam and acetic acid and the said first product mixture is fed into a second reaction zone wherein the ethylene and acetic acid react to form vinyl acetate in the presence of said second reaction catalyst. 
     
     
       14. The process of  claim 13 , wherein said first product mixture is fed directly into said second reaction zone without adding additional components. 
     
     
       15. The process of  claim 13 , wherein said first product mixture is fed into said second reaction zone with addition/adjustment of ethylene, acetic acid, oxygen or combinations thereof. 
     
     
       16. The process of  claim 13 , wherein said first product mixture is subjected to temperature and/or pressure adjustments prior to being fed into said second reaction zone. 
     
     
       17. A process of producing vinyl acetate monomer comprising the step of catalytically oxidizing ethane to form vinyl acetate in a single reaction zone containing a first catalyst having activity for oxidation of ethane to ethylene and acetic acid and a second catalyst having activity for oxidation of ethylene with acetic acid to vinyl acetate, wherein said first catalyst is at least one catalyst selected from the following catalyst compositions:
 a) a catalyst composition comprising consisting of the elements Mo, V, Nb, and Pd in the form of oxides, in the ratio Mo a V b Nb c Pd d  wherein:
 a is 1 to 5; 
 b is 0 to 0.5; 
 c is 0.01 to 0.5; and 
 d is >0 to 0.2; 
 
 b) a catalyst composition comprising consisting of the elements Mo, V, Pd, Nb, La and X, in the form of oxides, wherein X is Ga, Si, Al or Ge, in the ratio Mo a V b La c Pd d Nb e X f  wherein:
 a is 1; 
 b is 0.01 to 0.9; 
 c is >0 to 0.2; 
 d is >0 to 0.2; 
 e is >0 to 0.2; and 
 f is >0 to 0.3; and 
 
 c) a catalyst composition comprising consisting of the elements Mo, V, Nb and X which is selected from P, B, Hf, Te, As or mixtures thereof in the form of an oxide, in the following ratio Mo a V b Nb c X d  wherein: 
 a is 1 to 5; 
 b is >0 to 0.1; 
 c is 0.01 to 0.5; and 
 d is >0 to 0.1. 
 
     
     
       18. The process of  claim 17 , wherein said single reaction zone comprises a mixture of said first catalyst and said second catalyst. 
     
     
       19. The process of  claim 17 , wherein said single reaction zone comprises layers of said first reaction catalyst and said second catalyst. 
     
     
       20. The process of  claim 2 , wherein said process produces ethylene, acetic acid, VAM or combinations thereof. 
     
     
       21. A process for the production of vinyl acetate monomer comprising the steps of:
 (1) contacting a gaseous feed mixture of ethane or ethylene or ethane/ethylene, steam and a molecular oxygen containing gas in the presence of a first catalyst active for oxidation of ethane, ethylene or ethane/ethylene to produce a selective stream of acetic acid, ethylene, carbon dioxide and water, wherein the first catalyst is selected from the following catalyst compositions:
 a) a catalyst composition consisting of the elements Mo, V, Nb, and Pd, in the form of oxides, in the ratio Mo a V b Nb c ,Pd d  wherein:
 a is 1 to 5; 
 b is 0 to 0.5; 
 c is 0.01 to 0.5; and 
 d is >0 to 0.2; 
 
 b) a catalyst composition consisting of the elements Mo, V, Pd, Nb, La and X, in the form of oxides, wherein X is Al, Ga, Si or Ge, in the ratio Mo a V b La c Pd d Nb e X f  wherein:
 a is 1; 
 b is 0.01 to 0.9; 
 c is >0 to 0.2; 
 d is >0 to 0.2; 
 e is >0 to 0.2; and 
 f is >0 to 0.3; and 
 
 c) a catalyst composition consisting of the elements Mo, V, Nb and X which is selected from P, B, Hf, Te, As or mixtures thereof in the form of an oxide, in the following ratio Mo a V b Nb c X d  wherein:
 a is 1 to 5; 
 b is >0 to 0.1; 
 c is 0.01 to 0.5; 
 d is >0 to 0.1; and 
 
   (2) optionally adjusting the selective stream; and converting a second feed mixture comprising ethylene, acetic acid, and oxygen to vinyl acetate monomer in the presence of a second catalyst active for the production of vinyl acetate, wherein at least a portion of the ethylene, acetic acid, and oxygen in the second feed mixture are from the selective stream;   wherein no detectable or measurable levels of CO is produced when contacting said gaseous feed mixture in the presence of said first catalyst, and wherein said process does not include an intermediate separation step to remove CO between the production of the selective stream and the converting of the second feed mixture.   
     
     
       22. The process of claim 21, wherein said process produces no carbon monoxide. 
     
     
       23. The process of claim 22, wherein said first catalyst and second catalyst are in the form of a fixed or fluidized bed or a solid moving bed reactor. 
     
     
       24. The process of claim 22, wherein said gaseous feed mixture is fed into a second reaction zone. 
     
     
       25. The process of claim 24, wherein the second feed mixture for the second step comprises ethylene, acetic acid, CO 2  and oxygen. 
     
     
       26. The process of claim 22, wherein said gaseous feed mixture comprises molecular oxygen ranging from 0.1 to 25% by volume of the feed mixture. 
     
     
       27. The process of claim 22, wherein said gaseous feed mixture is diluted with N 2  in an amount ranging from 5 to 90% by volume. 
     
     
       28. The process of claim 22, wherein said gaseous feed mixture is diluted with steam in an amount ranging from 0 to 40% by volume. 
     
     
       29. The process of claim 22, wherein said gaseous feed mixture comprises firm 1% to 95% by volume of ethane, ethylene or mixtures thereof. 
     
     
       30. The process of claim 22, wherein first step oxidation is achieved at a temperature of from 150 to 450° C., under a pressure of from 15 to 600 psi, and with a contact time between reaction mixture and the catalyst of from 0.1 to 60 seconds. 
     
     
       31. The process of claim 22, wherein said contacting comprises reacting ethane or ethane/ethylene with steam and oxygen or a compound capable of providing oxygen in the presence of said first catalyst in a first reaction zone to form a first product mixture comprising ethylene, oxygen, steam and acetic acid and the said first product mixture is fed into a second reaction zone wherein the ethylene and acetic acid react to form vinyl acetate in the presence of said second catalyst. 
     
     
       32. The process of claim 31, wherein said first product mixture is fed directly into said second reaction zone without adding additional components. 
     
     
       33. The process of claim 31, wherein said first product mixture is fed into said second reaction zone with addition/adjustment of ethylene, acetic acid, oxygen or combinations thereof. 
     
     
       34. The process of claim 31, wherein said first product mixture is subjected to temperature and/or pressure adjustments prior to being fed into said second reaction zone.