Electrochemical conversion of polyalcohols to hydrocarbons

Abstract

A method of making hydrocarbons from polyalcohols, such as carbohydrates. The polyalcohols and carbohydrates may be provided from biomass, including paper, cardboard or urban generated paper product waste; wood and wood products, including forest slash and deadfall; agricultural waste; and the like. The polyalcohols and carbohydrates are combined with hydroiodic acid in aqueous solution to form the hydrocarbon and elemental iodine. Hydroiodic acid is then electrochemically regenerated by reducing the elemental iodine in a parallel reaction. A method of electrochemically generating hydroiodic acid from elemental iodine in aqueous solution is also described.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a flow chart for a method of making hydrocarbons from carbohydrates;

FIG. 2 is a flow chart for a method of electrochemically generating HI from elemental iodine in aqueous solution; and

FIG. 3 is a schematic representation of a two-compartment electrochemical cell in which the conversion of carbohydrates to hydrocarbons is carried out.

Claims

1. A method of making at least one hydrocarbon, the method comprising the steps of: a. providing at least one water-soluble polyalcohol to an aqueous solution in an electrochemical cell;b. providing a predetermined concentration of hydroiodic acid;c. combining the hydroiodic acid with the at least one water-soluble polyalcohol in the aqueous solution to form elemental iodine and the at least one hydrocarbon; andd. electrochemically regenerating hydroiodic acid from the elemental iodine generated by the reaction of the at least one water-soluble polyalcohol with hydroiodic acid within the electrochemical cell.

2. The method according to claim 1, wherein the at least one water-soluble polyalcohol includes at least one water-soluble carbohydrate.

3. The method according to claim 2, wherein the at least one water-soluble carbohydrate comprises at least one of a sugar, a starch, and a fiber.

4. The method according to claim 3, wherein the at least one water-soluble carbohydrate comprises at least one sugar selected from the group consisting of glucose, fructose, galactose, sucrose, lactose, and maltose.

5. The method according to claim 3, wherein the fiber is a biomass derived from at least one of paper, paper product waste, wood, wood products, agricultural waste, and combinations thereof.

6. The method according to claim 5, wherein the step of providing at least one water-soluble polyalcohol to an aqueous solution in an electrochemical cell comprises digesting the biomass to convert at least a portion of the biomass into the at least one water-soluble carbohydrate.

7. The method according to claim 2, wherein the at least one water-soluble carbohydrate comprises sorbitol, and wherein the at least one hydrocarbon comprises hexane.

8. The method according to claim 1, wherein the electrochemical cell comprises an anodic compartment having an anode disposed therein, a cathodic compartment having a cathode disposed therein, and a cationic membrane separating the anodic compartment and a cathodic compartment, wherein the cationic membrane is permeable with respect to protons and impermeable with respect to hydroiodic acid, elemental iodine, water-soluble polyalcohols, and hydrocarbons.

9. The method according to claim 8, wherein the step of combining the hydroiodic acid with the at least one water-soluble polyalcohol in the aqueous solution to form the at least one hydrocarbon and elemental iodine comprises combining the hydroiodic acid with the at least one water-soluble polyalcohol in the aqueous solution in the cathodic compartment to form the at least one hydrocarbon and elemental iodine.

10. The method according to claim 8, wherein the step of regenerating hydroiodic acid from the elemental iodine comprises: a. providing a predetermined potential across the cathode and anode;b. electrochemically oxidizing water to form oxygen gas and protons in the anodic compartment;c. diffusing the protons through the cationic membrane from the anodic compartment through the cationic membrane into the cathodic compartment;d. electrochemically reducing the elemental iodine to form iodide ions in the cathodic compartment; ande. reacting the protons with the elemental iodide ions to regenerate the hydroiodic acid in the cathodic compartment.

11. The method according to claim 10, wherein the predetermined potential is less than the voltage needed to electrolyze water.

12. The method according to claim 1, wherein the predetermined concentration of hydroiodic acid is in a range from about 5 M to about 10 M.

13. A method of electrochemically generating hydroiodic acid from elemental iodine in aqueous solution, the method comprising the steps of: a. providing an electrochemical cell, the electrochemical cell comprising an anodic compartment having an anode disposed therein, a cathodic compartment having a cathode disposed therein, and a cationic membrane separating the anodic compartment and the cathodic compartment, wherein the cationic membrane is permeable with respect to protons and impermeable with respect to hydroiodic acid, elemental iodine, water-soluble polyalcohols, and hydrocarbons;b. providing the aqueous solution containing elemental iodine to the cathodic compartment of the electrochemical cell;c. providing a predetermined potential across the cathode and anode;d. electrochemically oxidizing water to form oxygen gas and protons in the anodic compartment;e. diffusing the protons from the anodic compartment through the cationic membrane into the cathodic compartment;f. electrochemically reducing the elemental iodine to form iodide ions in the cathodic compartment; andg. reacting the protons with the elemental iodide ions to regenerate the hydroiodic acid in the cathodic compartment.

14. The method according to claim 13, wherein the predetermined potential is less than the voltage needed to electrolyze water.

15. A method of making at least one of a hydrocarbon fuel and an oxygenated fuel, the method comprising the steps of: a. providing an electrochemical cell, the electrochemical cell comprising an anodic compartment having an anode disposed therein, a cathodic compartment having a cathode disposed therein, and a cationic membrane separating the anodic compartment and the cathodic compartment, wherein the cationic membrane is permeable with respect to protons and impermeable with respect to hydroiodic acid, elemental iodine, water-soluble carbohydrates, and hydrocarbons;b. providing at least one water-soluble carbohydrate to an aqueous solution in the cathodic compartment, wherein the at least one water-soluble carbohydrate is derived from a biomass;c. providing a predetermined concentration of hydroiodic acid;d. combining the hydroiodic acid with the at least one water-soluble carbohydrate in the aqueous solution to form at least one of the hydrocarbon fuel and the oxygenated fuel and elemental iodine;e. providing a predetermined potential across the cathode and anode;f. electrochemically oxidizing water to form oxygen gas and protons in the anodic compartment;g. diffusing the protons through the cationic membrane from the anodic compartment through the cationic membrane into the cathodic compartment;h. electrochemically reducing the elemental iodine to form iodide ions in the cathodic compartment; andi. reacting the protons with the elemental iodide ions to regenerate the hydroiodic acid in the cathodic compartment.

16. The method according to claim 15, wherein the at least one water-soluble carbohydrate comprises at least one of a sugar, a starch, and a fiber.

17. The method according to claim 16, wherein the at least one water-soluble carbohydrate comprises at least one sugar selected from the group consisting of glucose, fructose, galactose, sucrose, lactose, and maltose.

18. The method according to claim 15, wherein the biomass is derived from at least one of paper, paper product waste, wood, wood products, agricultural waste, and combinations thereof.

19. The method according to claim 15, wherein step of providing at least one water-soluble carbohydrate to an aqueous solution in an electrochemical cell comprises digesting the biomass to convert at least a portion of the biomass into the at least one water-soluble carbohydrate.

20. The method according to claim 15, wherein the at least one carbohydrate comprises sorbitol, and wherein the hydrocarbon comprises hexane.

21. The method according to claim 15, wherein the predetermined potential is less than the voltage needed to electrolyze water.

22. The method according to claim 15, wherein the predetermined concentration of hydroiodic acid is in a range from about 5 M to about 10 M.

23. The method according to claim 15, wherein the oxygenated fuel comprises ethanol.