Processes for preparing diacids, dialdehydes and polymers
View Patent ↗Alcohols are catalytically oxidized to aldehydes, in particular to benzaldehyde and diformylfuran, which are useful as intermediates for a multiplicity of purposes. The invention also relates to the polymerization of the dialdehyde and to the decarbonylation of the dialdehyde to furan.
1. A process for the preparation of a diacid of the formula HOOC—R′—COOH from an alcohol/aldehyde of the formula HOH 2 C—R′—(C═O)H, wherein R′ is an optionally substituted furan ring, comprising the steps:
(a) contacting the alcohol/aldehyde with an oxidant in the presence of a metal bromide catalyst forming a dialdehyde having the formula H(C═O)—R′—(C═O)H, and optionally isolating the dialdehyde;
(b) contacting the dialdehyde with an oxidant in the presence of a metal bromide catalyst forming an acid/aldehyde having the formula HOOC—R′—(C═O)H, and optionally isolating the acid/aldehyde; and
(c) contacting the acid/dialdehyde with an oxidant in the presence of a metal bromide catalyst forming the diacid, and optionally isolating the diacid.
2. The process of claim 1 wherein the product of the reaction is isolated following steps a, b or c.
3. The process of claim 1 wherein the process is run in a solvent or solvent mixture comprising at least one aliphatic C 2 -C 6 monocarboxylic acid solvent compound.
4. The process of claim 3 wherein the process is run in acetic acid.
5. The process of claim 3 wherein the metal bromide catalyst comprises a source of bromine and at least one metal selected from the group consisting of Co and Mn.
6. The process of claim 5 wherein the metal bromide catalyst further comprises Zr.
7. The process of claim 6 wherein the catalyst comprises Co and Mn.
8. The process of claim 4 wherein the process further comprises converting the alcohol/aldehyde of the formula HOH 2 C—R′—(C═O)H to an acetate ester of the formula CH 3 (C═O)OCH 2 —R′—(C═O)H.
9. The process of claim 8 wherein the diacid is furan-2,5-dicarboxylic acid and the alcohol/aldehyde is 5-(hydroxymethyl)furfural.