Phosphonic acid catalyst in dehydrative cyclization of 5 and 6 carbon polyols with improved color and product accountability

Patent metadata

Field	Value
Publication number	US-9856195-B2
Application number	US-201415302400-A
Country	US
Kind code	B2
Filing date	Dec 12, 2014
Priority date	Apr 10, 2014
Publication date	Jan 2, 2018
Grant date	Jan 2, 2018

Abstract

A process for preparing cyclic dehydration products from sugar alcohols is described. The process involve using a mixed-acid catalyst reaction mixture containing a reducing acid, having a pKa of about 1.0-1.5, and at least a strong Brønsted acid or a Lewis acid, having a pKa≦0, or both acids in a solution to dehydrate and ring close said sugar alcohol. Synergistically, the mixed-acid catalysis can produce greater amounts of the desired product at similar levels of compositional accountability than either of the component acid catalysts acting alone.

First claim

We claim:

1. A process for preparing a cyclic dehydration product comprising: contacting a sugar alcohol with a homogeneous mixed-acid catalyst reaction mixture containing a reducing Brønsted acid, having a pKa of about 1.0-1.5, in combination with a water-tolerant Lewis acid selected from the group consisting of: aluminum trifluoromethanesulfonate (Al(OTf) 3 ), gallium trifluoromethanesulfonate (Ga(OTf) 3 , bismuth trifluoromethanesulfonate (Bi (OTf) 3 ), scandium trifluoromethanesulfonate (Sc(OTf) 3 ), indium trifluoromethanesulfonate (In(OTf) 3 ), tin triflate (Sn(OTf) 2 ), and hafnium triflate (Hf(OTf) 4 ) at a temperature for a sufficient time to dehydrate and ring close said sugar alcohol to a corresponding cyclic dehydration product of the sugar alcohol in a product mixture.

2. The process according to claim 1 , wherein said sugar alcohol is at least one of: sorbitol, mannitol, iditol, xylitol, erythritol, and 1,2,5,6-hexanetetrol (HTO).

3. The process according to claim 1 , wherein said reducing Brønsted acid is phosphonic acid (H 3 PO 3 ).

4. The process according to claim 1 , wherein a molar ratio of said reducing Brønsted acid to said water-tolerant Lewis acid is from about 1000:1 to about 5:1.

5. The process according to claim 1 , wherein said temperature is greater than 130° C. to about 190° C.

6. The process according to claim 1 , wherein said reducing Brønsted acid is present at a concentration of about 1.0 mol % to about 20 mol % relative to the sugar alcohol.

7. The process according to claim 1 , wherein said Brønsted acid is present at a concentration of about 0.01 mol % to about 2.0 mol % relative to the sugar alcohol.

8. The process according to claim 1 , wherein said Lewis acid is present at a concentration of about 0.005 mol % to about 0.5 mol % relative to the sugar alcohol.

Assignees

• Archer Daniels Midland Co
• Archer-Daniels Midland Company

Inventors

• Stensrud Kenneth
• Sanborn Alexandra
• Howard Stephen
• Hagberg Erik

Classifications

• C07D493/04 Primary

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• C07C29/154

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• B01D15/361

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• B01D15/1821

  Simulated moving beds · CPC title

• B01D3/10

  Vacuum distillation (B01D3/12 takes precedence) · CPC title