Process and intermediates for the production of furan-2,5-dicarboxylic acid or derivatives thereof
Disclosed is a method of making 5-formyl-2-furoic acid and furan-2,5-dicarboxylic acid. The method involves the use of 5-keto-aldonic acids as intermediates, as these can be subjected to ring formation by a cyclodehydration reaction under mild conditions. The 5-formyl-2-furoic acid or carboxylic derivative thereof is subjected to oxidation so as to form furan-2,5-dicarboxylic acid. The 5-keto-aldonic acid intermediates can be obtained by isomerization of uronic acids which can be obtained from sugar beet pulp, chicory pulp, fruit peals including orange peels, or non-terrestrial sources like seaweeds. A preferred source is sugar beet pulp.
1. A process for the preparation of furan-2,5-dicarboxylic acid, or a carboxylic derivative thereof, comprising making 5-formyl-2-furoic acid, or a carboxylic derivative thereof, by a method comprising the steps of (i) providing an uronic acid; (ii) subjecting the uronic acid to isomerization so as to form the corresponding 5-keto-aldonic acid; (iii) subjecting said 5-keto-aldonic acid to cyclodehydration so as to produce 5-formyl-2-furoic acid or a carboxylic derivative thereof, and subjecting the 5-formyl-2-furoic acid, or the carboxylic derivative thereof, to oxidation so as to form furan-2,5-dicarboxylic acid, or a carboxylic derivative thereof.
2. A process according to claim 1 , wherein the oxidation is conducted by subjecting the 5-formyl-2-furoic acid or carboxylic derivative thereof to molecular oxygen under the influence of a supported noble metal catalyst, preferably selected from the group consisting of gold, platinum, ruthenium and palladium.
3. A process according to claim 2 , wherein the oxidation is conducted in the presence of a base.
4. A process according to claim 3 , wherein the catalyst support is carbon.
5. A process according to claim 1 , wherein the uronic acid is obtained from bio-based pectins or biobased alginates.
6. A process for the preparation of 5-formyl-2-furoic acid, or a carboxylic derivative thereof, from an uronic acid obtained from bio-based pectins or biobased alginates, the method comprising the steps of (i) providing an uronic acid obtained from bio-based pectins or biobased alginates; (ii) subjecting the uronic acid to isomerization so as to form the corresponding 5-keto-aldonic acid; (iii) subjecting said 5-keto-aldonic acid to cyclodehydration so as to produce 5-formyl-2-furoic acid or a carboxylic derivative thereof.
7. A process according to claim 6 , wherein the uronic acid is selected from the group consisting of D-galacturonic acid, D-glucuronic acid, D-mannuronic acid, and mixtures thereof.
8. A process according to claim 6 , wherein the 5-formyl-2-furoic acid or a carboxylic derivative thereof is C 1-12 alkyl-5-formyl-2-furoate, preferably C 1-4 alkyl-5-formyl-2-furoate.
9. A process according to claim 6 , wherein the isomerization step is conducted in water in the presence of calcium hydroxide, or a calcium salt under alkaline conditions.
10. A process according to claim 6 , wherein the cyclodehydration step is conducted in a solvent in the presence of an acid catalyst.
11. A process according to claim 10 , wherein the acid is a Brønstedt acid, preferably selected from the group consisting of HCl, sulfuric acid, formic acid, acetic acid, oxalic acid, hydrobromic acid, phosphorous acid, and p-toluene sulfonic acid.
12. A process according to claim 10 , wherein the acid is a Lewis acid selected from the group consisting of ZnCl 2 , CuCl 2 , BF 3 —OEt 2 , and lanthanide salts.
13. A bio-based process for the synthesis of furan-2,5-dicarboxylic acid, or a carboxylic derivative thereof, the process comprising the steps of (i) providing at least one bio-based uronic acid; (ii) subjecting the at least one uronic acid to isomerization so as to form the corresponding 5-keto-aldonic acid; (iii) subjecting said 5-keto-aldonic acid to cyclodehydration so as to produce 5-formyl-2-furoic acid or a carboxylic derivative thereof, subjecting the 5-formyl-2-furoic acid, or the carboxylic derivative thereof, to oxidation so as to form furan-2,5-dicarboxylic acid, or a carboxylic derivative thereof.
14. A process according to claim 10 , wherein the solvent is selected from the group consisting of methanol, ethanol, water, biphasic systems, and mixtures thereof.
15. A process according to claim 14 , wherein the biphasic system comprises water/methyl isobutyl ketone.