Method for the preparation of 2,5-furandicarboxylic acid and for the preparation of the dialkyl ester of 2,5-furandicarboxylic acid
A method for the preparation of 2,5-furan dicarboxylic acid includes the step of contacting a feed comprising a compound selected from the group consisting of 5-hydroxymethylfurfural (“HMF”), an ester of 5-hydroxymethyl-furfural, 5-methylfurfural, 5-(chloromethyl)furfural, 5-methylfuroic acid, 5-(chloromethyl)furoic acid, 2,5-dimethylfuran and a mixture of two or more of these compounds with an oxidant in the presence of an oxidation catalyst at a temperature higher than 140° C.
1. A method for the preparation of 2,5-furan dicarboxylic acid comprising the step of contacting a feed comprising a compound selected from the group consisting of 5-hydroxymethylfurfural (“HMF”), an ester of 5-hydroxymethylfurfural, 5-methylfurfural, 5-(chloromethyl)furfural, 5-methylfuroic acid, 5-(chloromethyl)furoic acid, 2,5-dimethylfuran and a mixture of two or more of these compounds with an oxygen-containing gas, in the presence of an oxidation catalyst comprising both Co and Mn, and further a source of bromine, at a temperature between 140° C. and 200° C. at an oxygen partial pressure of 1 to 10 bar, wherein a solvent or solvent mixture comprising acetic acid or acetic acid and water mixtures is present.
2. The method according to claim 1 , wherein the feed comprises a compound selected from the group consisting of 5-hydroxymethylfurfural (“HMF”), esters of HMF and a mixture thereof.
3. The method according to claim 1 , wherein the oxidation catalyst comprises at least one additional metal.
4. The method according to claim 3 , wherein the additional metal is Zr and/or Ce.
5. The method according to claim 1 , wherein the temperature is between 160 and 190° C.
6. The method according to claim 1 , wherein the feed comprises an ester of HMF having an ester moiety of an alkyl carboxylic acid wherein the alkyl group has up to 6 carbon atoms.
7. A process for the preparation of a dialkyl ester of 2,5,-furan dicarboxylic acid, comprising the step of contacting a feed comprising a compound selected from the group consisting of 5-hydroxymethylfurfural (“HMF”), an ester of 5-hydroxymethyl-furfural, 5-methylfurfural, 5-(chloromethyl)furfural, 5-methylfuroic acid, 5-(chloromethyl)furoic acid, 2,5-dimethylfuran and a mixture of two or more of these compounds with an oxygen-containing gas in the presence of an oxidation catalyst comprising both Co and Mn, and further a source of bromine, at a temperature between 140° C. and 200° C. at an oxygen partial pressure of 1 to 10 bar, wherein a solvent or solvent mixture comprising acetic acid or acetic acid and water mixtures is present, and esterifying the thus obtained product.
8. The process according to claim 7 , wherein the product is esterified with a C1-C5 alkyl alcohol.
9. The process according to claim 8 , wherein the C1-C5 alkyl alcohol is methanol and the dialkyl ester is the dimethylester of 2,5-furan dicarboxylic acid.
10. A method according to claim 2 , wherein the feed comprises an HMF ester and optionally 5-hydroxymethyl furfural, which has been obtained by converting a carbohydrate source in the presence of an alkyl carboxylic acid.