PRODUCTION OF FORMIC ACID

• US 20100234638A1
• Filed: 03/11/2009
• Published: 09/16/2010
• Est. Priority Date: 03/11/2009
• Status: Active Grant

• Current Assignee: Biofire Technologies Inc.
• Original Assignee: Biofire Technologies Inc.
• Inventors: Fitzpatrick, Stephen W.
• Granted Patent: US 8,138,371 B2
• Time in Patent Office: Days
• US Class Current: 562/515
• CPC Class Codes: C07C 51/00 Preparation of carboxylic acids or their salts, halides or anhydrides of acids by hydrolysis of oils, fats or waxes C11C
• CPC Class Codes: C07C 51/44 by distillation
• CPC Class Codes: C07C 53/02 Formic acid
• CPC Class Codes: C07C 59/347 containing keto groups

Abstract

Processes for producing formic acid from a carbohydrate-containing material include hydrolyzing a carbohydrate-containing material (e.g., cellulose) in the presence of a mineral acid to form an intermediate hydrolysate comprising one or more sugars, and hydrolyzing the intermediate hydrolysate to form a hydrolysate product including formic acid.

Claims

1. A process for producing formic acid from a carbohydrate-containing material, the process comprising:

introducing a carbohydrate-containing material to a first reactor;

hydrolyzing the carbohydrate-containing material in the first reactor in the presence of a mineral acid for a first time period at a first temperature and a first pressure effective to form an intermediate hydrolysate comprising one or more sugars;

transferring the intermediate hydrolysate from the first reactor to a second reactor;

hydrolyzing the intermediate hydrolysate in the second reactor for a second time period at a second temperature less than 195 degrees C. and a second pressure effective to form a hydrolysate product comprising formic acid; and

isolating the formic acid in a vapor from the hydrolysate product.

2. The process of claim 1, wherein the carbohydrate-containing material is hydrolyzed in the first reactor at a first temperature of 190 to 205 degrees C.

3. The process of claim 1, wherein the carbohydrate-containing material is hydrolyzed in the first reactor with the mineral acid at 1 to 10% wt of the contents of the first reactor.

4. The process of claim 1, wherein the carbohydrate-containing material is hydrolyzed in the first reactor for a first time period of 10 to 60 seconds.

5. The process of claim 1, wherein the carbohydrate-containing material is hydrolyzed in the first reactor for a first time period of 10 to 60 seconds, at a first temperature of 190 to 205 degrees C., and at a first pressure effective to maintain the intermediate hydrolysate as a fluid;

and wherein the mineral acid is present in the first reactor at 2 to 5% wt of the contents of the first reactor.

6. The process of claim 1, wherein the intermediate hydrolysate is hydrolyzed in the second reactor at a second temperature that is lower than the first temperature.

7. The process of claim 1, wherein the intermediate hydrolysate is hydrolyzed in the second reactor at a second temperature of 150 to 195 degrees C.

8. The process of claim 1, wherein the intermediate hydrolysate is hydrolyzed in the second reactor for a second time period of 10 to 60 minutes.

9. The process of claim 1, wherein the intermediate hydrolysate is hydrolyzed in the second reactor for a second time period of 10 to 60 minutes, at a second temperature that is less than the first temperature and above the boiling point of the intermediate hydrolysate, and at a second pressure effective to maintain the intermediate hydrolysate as a fluid in the second reactor.

10. The process of claim 1, further comprising the step of isolating additional formic acid from a liquid phase of the hydrolysate product obtained from the second reactor by evaporating the formic acid from the liquid phase of the hydrolysate product.

11. The process of claim 1, wherein the hydrolysate product further comprises levulinic acid, and the formic acid is isolated from the second reactor with a molar ratio of the levulinic acid to the formic acid of at least 0.9.

12. The process of claim 5, wherein

the intermediate hydrolysate is hydrolyzed in the second reactor for a second time period of 10 to 60 minutes, at a second temperature that is less than the first temperature and at the boiling point of the intermediate hydrolysate, and at a second pressure effective to maintain the intermediate hydrolysate as a fluid;

and

the hydrolysate product further comprises levulinic acid, and the formic acid in the outlet stream from the second reactor has a molar ratio of the levulinic acid to the formic acid of at least 0.9.

13. A continuous process for producing formic acid from a carbohydrate- containing material using a first reactor and a second reactor, the process comprising

continuously supplying the carbohydrate-containing material into the first reactor;

hydrolyzing the carbohydrate-containing material in the first reactor in the presence of a mineral acid in an amount of 1 to 10% wt of the carbohydrate-containing material in the first reactor for a first time period, at a first temperature of 195 to 235 degrees C. and a first pressure effective to hydrolyze at least a portion of the carbohydrate-containing material to form an intermediate hydrolysate comprising one or more sugars;

continuously transferring the intermediate hydrolysate from the first reactor to a second reactor;

hydrolyzing the intermediate hydrolysate in the second reactor for a second time period that is greater than the first time period, at a second temperature of 150 to 210 degrees C. and a second pressure to form a hydrolysate product comprising formic acid and levulinic acid in the second reactor, wherein the second temperature and the second pressure are selected to maintain the intermediate hydrolysate as a fluid in the second reactor; and

continuously removing the formic acid in a vapor from the second reactor in an amount that provides a molar ratio of the levulinic acid to the formic acid of at least 0.8.

14. The continuous process of claim 13, wherein the carbohydrate-containing material is hydrolyzed in the first reactor with mineral acid in an amount of 3 to 4.5% wt of the carbohydrate-containing material in the first reactor, and at first temperature of 205 to 220 degrees C. for a first time period of 10 to 30 seconds.

15. The continuous process of claim 13, wherein the intermediate hydrolysate is hydrolyzed in the second reactor at second temperature of 170 to 195 degrees C. for a second time period of 20 to 35 minutes.

16. The continuous process of claim 13, wherein the second pressure is lower than the first pressure.

17. The continuous process of claim 13, wherein the carbohydrate-containing material consists essentially of cellulose-containing material.

18. A process for producing formic acid from a carbohydrate-containing material, the process comprising:

introducing a carbohydrate-containing material to a first reactor;

hydrolyzing the carbohydrate-containing material in the first reactor in the presence of a mineral acid in an amount of 3.0 to 4.5% wt of the carbohydrate-containing material in the first reactor for a first time period at a first temperature and a first pressure effective to form an intermediate hydrolysate comprising one or more sugars;

transferring the intermediate hydrolysate from the first reactor to a second reactor;

hydrolyzing the intermediate hydrolysate in the second reactor for a second time period at a second temperature and a second pressure effective to form a hydrolysate product comprising formic acid; and

isolating the formic acid in a vapor from the hydrolysate product.

19. The process of claim 18, wherein the carbohydrate-containing material is hydrolyzed in the first reactor at first temperature of 205 to 220 degrees C. for a first time period of 10 to 30 seconds;

and the intermediate hydrolysate is hydrolyzed in the second reactor at second temperature of 170 to 195 degrees C. for a second time period of 20 to 35 minutes.

20. The process of claim 18, wherein the carbohydrate-containing material consists essentially of cellulose.

21. (canceled)