Variations on prins-like chemistry to produce 2,5-dimethylhexadiene from isobutanol

• US 8,742,187 B2
• Filed: 04/19/2012
• Issued: 06/03/2014
• Est. Priority Date: 04/19/2011
• Status: Active Grant

• Current Assignee: Gevo Incorporated
• Original Assignee: Gevo Incorporated
• Inventors: Taylor, Thomas Jackson, Taylor, Joshua D., Peters, Matthew W., Henton, David E.
• Primary Examiner(s): Dang, Thuan D
• Application Number:
  US13/451,026
• Publication Number:
  US 20120271082A1
• Time in Patent Office: 775 Days
• Field of Search: 585/322, 585/319, 585/408, 585/603, 568/437
• US Class Current: 585/322
• CPC Class Codes: C07C 1/24 by elimination of water
• CPC Class Codes: C07C 11/09 Isobutene
• CPC Class Codes: C07C 11/12 Alkadienes
• CPC Class Codes: C07C 15/08 Xylenes
• CPC Class Codes: C07C 2/867 the non-hydrocarbon is an aldehyde or a ketone
• CPC Class Codes: C07C 45/002 by dehydrogenation
• CPC Class Codes: C07C 47/02 Saturated compounds having —CHO groups bound to acyclic carbon atoms or to hydrogen
• CPC Class Codes: C07C 5/393 with cyclisation to an aromatic six-membered ring, e.g. dehydrogenation of n-hexane to benzene
• CPC Class Codes: Y02P 20/52 using catalysts, e.g. selective catalysts

Abstract

The method of the present invention provides a high yield pathway to 2,5-dimethylhexadiene from renewable isobutanol, which enables economic production of renewable p-xylene (and subsequently, terephthalic acid, a key monomer in the production of PET) from isobutanol. In addition, the present invention provides methods for producing 2,5-dimethylhexadiene from a variety of feed stocks that can act as “equivalents” of isobutylene and/or isobutyraldehyde including isobutanol, isobutylene oxide, and isobutyl ethers and acetals. Catalysts employed in the present methods that produce 2,5-dimethylhexadiene can also catalyze alcohol dehydration, alcohol oxidation, epoxide rearrangement, and ether and acetal cleavage.

Claims

1. A method for preparing xylenes, comprising:

a. providing a feedstock comprising isobutanol;

b. at least partially oxidizing a portion of said isobutanol to form a first stream comprising isobutyraldehyde and isobutanol;

c. coupling said isobutyraldehyde with isobutylene to form a second stream comprising 2,5-dimethyl-2,4-hexadiene; and

d. dehydrocyclizing said 2,5-dimethyl-2,4-hexadiene to form a product stream comprising said xylenes.

2. The method of claim 1, wherein said isobutanol feedstock comprises renewable isobutanol.

3. The method of claim 2, wherein said isobutanol feedstock is renewable isobutanol.

4. The method of claim 1, wherein said isobutylene is formed via selective dehydration of said isobutanol in said first stream prior to said reacting step c.

5. The method of claim 1, wherein said xylenes comprise o-xylene and p-xylene.

6. The method of claim 1, further comprising separating said xylenes from said product stream.

7. The method of claim 1, wherein oxidizing comprises treating said stream with an oxidizing agent.

8. The method of claim 1, wherein said reacting step b comprises contacting said reaction mixture with a catalyst.

9. The method of claim 8, wherein said catalyst comprises niobic acid and its hydrates.

10. The method of claim 1, wherein the ratio of isobutyraldehyde to isobutanol in said first stream is about 1:

1.

11. The method of claim 1, further comprising conducting said coupling step c in the presence of water.

12. The method of claim 1, further comprising conducting said coupling step c in the absence of water.

13. The method of claim 11, further comprising conducting said coupling step in the presence of an acid.

14. The method of claim 1, wherein said second stream further comprises one or more saturated or unsaturated mono- or polyhydroxylated octanes.

15. The method of claim 14, wherein said one or more octanes comprise 2,5-dimethylhex-4-en-3-ol and 2,5-dimethylhexane-2,4-diol.

16. The method of claim 14, further comprising dehydrating said one or more saturated or unsaturated mono- or polyhydroxylated octanes.

17. The method of claim 1, wherein said oxidizing comprises dehydrogenating.