Processes for preparing 2,5-furandicarboxylic acid and esters thereof
A process for producing furan dicarboxylic acid or an ester thereof from a feedstock comprising hydroxymethyl furfural (HMF) and humins is disclosed. Humins are a byproduct from reactions forming HMF from sugars and are typically removed from the HMF prior to any further processing. A humins-containing HMF feedstock is utilized to produce furan dicarboxylic acids and ester substantially free from humins.
1. A process comprising:
a) oxidizing a feedstock comprising hydroxymethyl furfural and humins to produce a mixture comprising crude humins-containing 2,5-furan dicarboxylic acid;
b) separating the mixture to obtain a solid 2,5-furan dicarboxylic acid/humins composition;
c) esterifying the solid 2,5-furan dicarboxylic acid/humins composition with an alcohol to produce a crude ester of 2,5-furan dicarboxylic acid; and
d) purifying the crude ester of 2,5-furan dicarboxylic acid obtained in step c) by distillation or by sublimation to produce a purified ester of 2,5-furan dicarboxylic acid comprises less than 100 ppm humins as determined by size exclusion chromatography.
2. The process of claim 1 wherein the purified ester of 2,5-furan dicarboxylic acid is 2,5-furan dicarboxylic acid dimethyl ester.
3. A process comprising:
i) oxidizing a feedstock comprising hydroxymethyl furfural and humins in a solvent to produce a mixture comprising crude humins-containing 2,5-furan dicarboxylic acid;
ii) filtering the mixture under high temperature to obtain a filtrate comprising 2,5-furan dicarboxylic acid comprises less than 100 ppm humins as determined by size exclusion chromatography, wherein the filtration temperature is sufficiently high to keep the 2,5-furan dicarboxylic acid soluble in the solvent;
iii) esterifying the 2,5-furan dicarboxylic acid substantially free of humins with an alcohol to produce a crude ester of 2,5-furan dicarboxylic acid; and
iv) purifying the crude ester of 2,5-furan dicarboxylic acid obtained in step iii) by distillation or sublimation to obtain a purified ester.
4. The process of claim 3 wherein the ester of 2,5-furan dicarboxylic acid is 2,5-furan dicarboxylic acid dimethyl ester.
5. The process of claim 3 wherein the high temperature of the filtration step ii) is in the range of from 50° C. to 200° C.
6. The process of claim 3 wherein the solvent is acetic acid or acetic acid and water.
7. The process of claim 3 wherein the purified ester of 2,5-furan dicarboxylic acid comprises less than 100 ppm humins as determined by size exclusion chromatography, a b* value of less than 3 as determined by LAB color measurement, and greater than 99 percent by weight of the diester of 2,5-furan dicarboxylic acid, based on the total weight of the purified ester of 2,5-furan dicarboxylic acid.
8. The process of claim 3 , wherein at least a portion of the alcohol is replaced with an alcohol source.
9. The process of claim 1 wherein the purified ester of 2,5-furan dicarboxylic acid comprises a b* value of less than 3 as determined by LAB color measurement, and greater than 99 percent by weight of the diester of 2,5-furan dicarboxylic acid, based on the total weight of the purified ester of 2,5-furan dicarboxylic acid.
10. The process of claim 1 , wherein at least a portion of the alcohol is replaced with an alcohol source.