Patent ID: 8558018

Claim:
A method of oxidizing furan aldehydes comprising heating the furan aldehyde in a reaction mixture comprising a solvent containing dissolved oxygen and at least one catalyst selected from the group consisting of Co(II), Mn(II), Ce(III) and salts thereof, wherein: (i) if the furan aldehyde is -5-(hydroxymethyl)furfural, the reaction mixture comprises an aliphatic ketone and a predominant reaction product of the oxidizing is diformylfuran; OR (ii) if the furan aldehyde is a 5-ether of the furan aldehyde, the predominant reaction product is at least one of a 5-ester furan 2-acid and a 5-(alkoxycarbonyl)furfural; OR (iii) if the furan aldehyde is a 5-(alkoxycarbonyl)furfural the predominant reaction product is a 5-ester furan 2-carboxylic acid; OR— (iv) if the furan is a 5-(alkoxymethyl)furoic acid the product is a 5-ester furan 2-carboxylic acid.