Ionic liquids processing of biomass to reducing sugars and other dehydration products

• US 8,575,374 B1
• Filed: 10/21/2010
• Issued: 11/05/2013
• Est. Priority Date: 10/21/2010
• Status: Active Grant

• Current Assignee: United States Of America As Represented By The Secretary Of The Air Force
• Original Assignee: United States Of America As Represented By The Secretary Of The Air Force
• Inventors: DeLong, Hugh C., Trulove, Paul C., Mantz, Robert A., Reichert, William M., Mandia, Jeremy
• Primary Examiner(s): Loewe, Sun Jae
• Application Number:
  US12/908,986
• Time in Patent Office: 1,111 Days
• Field of Search: None
• US Class Current: 549/548
• CPC Class Codes: C07D 233/60 with hydrocarbon radicals, substituted by oxygen or sulfur atoms, attached to ring nitrogen atoms

Abstract

The present invention describes the use of an ionic liquid acid catalyst for the hydrolysis of cellulose into reducing sugars and other degradation products. The use of an ionic liquid catalyst for the hydrolysis of cellulose provides a low volatility catalyst and eliminates the hazards associated with the handling of mineral acids. Conditions such as temperature, catalyst modification, and ionic liquid solvent control the production of reducing sugars and other products. The combination of using an ionic liquid as the solvent for cellulose and ionic liquid catalyst provides an unprecedented tunability of the reaction properties giving more control over the conversion process to produce dehydration products with higher yields depending on the desired feedstock.

Claims

1. A method for the depolymerization of a biomass selected from the group consisting of cellulose, hemicelluloses, lignocelluloses and mixtures thereof, comprising dissolving the biomass in an homogeneous solution comprising an ionic liquid solvent and an ionic liquid catalyst.

2. A method according to claim 1 wherein said ionic liquid catalyst is an ionic liquid comprised of cations and anions with a melting point below 150°

C. that effects a change in the rate of the depolymerization of the biomass into degradation products but is not consumed by the reaction itself.

3. A method according to claim 1 wherein said depolymerization of biomass dissolved in an ionic liquid solvent results in degradation products selected from the group consisting of glucose, fructose, glyceraldehyde, lactose, arabinose, maltose, hydroxymethylfurfural, furfural, levulinic acid, and mixtures thereof, wherein the depolymerization reaction rates are facilitated by heating and stirring of the biomass, the ionic liquid solvent and ionic liquid catalyst solution.

4. A method according to claim 3 wherein said biomass is cellulose.

5. A method according to claim 4 wherein the degradation products are selected from the group consisting of glucose, fructose, glyceraldehyde, lactose, arabinose, and maltose.

6. A method according to claim 4 wherein said ionic liquid solvent is selected from the group consisting of 1-methyl-3-ethylimidazolium chloride, 1-methyl-3-ethylimidazolium acetate, 1-methyl-3-butylimidazolium chloride, 1-methyl-3-butylimidazolium acetate, and mixtures thereof.

7. A method according to claim 4 wherein said ionic liquid catalyst is selected from the group consisting of 1-methyl-3-(propyl-4-sulfonic acid)imidazolium triflate, 1-methyl-3-(butyl-4-sulfonic acid)imidazolium triflate, and mixtures thereof.

8. A method according to claim 4 wherein said ionic liquid catalyst is 1-methyl-3-(butyl-4-sulfonic acid)imidazolium triflate.