Methods for producing 5-(halomethyl)furfural
The present disclosure provides methods to produce 5-(halomethyl)furfural, including 5-(chloromethyl)furfural, by acid-catalyzed conversion of C6 saccharides, including isomers thereof, polymers thereof, and certain derivatives thereof. The methods make use of acids with lower concentrations, and allows for conversion of sugars into 5-(halomethyl)furfural at higher temperatures and faster reaction or residence times.
1. A method for producing 5-(halomethyl)furfural, comprising: combining feedstock, aqueous acid, and halide salt to produce 5-(halomethyl)furfural,
wherein the feedstock comprises one or more C6 monosaccharides, disaccharides comprising monomeric units having six carbon atoms, or polysaccharides comprising monomeric units having six carbon atoms;
wherein the aqueous acid and the halide salt react to provide a halogen-containing mineral acid in situ; and
wherein the combination of the feedstock, the aqueous acid, and the halide salt has a hydrogen concentration of less than or equal to 8 M, and a halide concentration of at least 8 M.
2. The method of claim 1 , wherein the aqueous acid comprises protic acid.
3. The method of claim 1 , wherein the halide salt comprises lithium halide or calcium halide, or any combinations thereof.
4. The method of claim 1 , wherein the salt comprises calcium chloride, calcium bromide or a combination thereof.
5. The method of claim 1 , wherein the halogen-containing mineral acid provided in situ is a chloro-containing mineral acid.
6. The method of claim 1 , wherein the halogen-containing mineral acid provided in situ comprises hydrochloric acid, or hydrobromic acid, or a combination thereof.
7. The method of claim 1 , wherein the aqueous acid comprises protic acid;
wherein the halide salt comprises lithium chloride, or calcium chloride, or a combination thereof; and
wherein the aqueous acid and the halide salt react to provide hydrochloric acid in situ.
8. The method of claim 7 , wherein the aqueous acid comprises acids with pKa less than 5.
9. The method of claim 1 , wherein the hydrogen concentration is less than or equal to 2 M.
10. The method of claim 1 , wherein the hydrogen concentration is greater than or equal to 0.5 M and less than or equal to 8 M.
11. The method of claim 1 , wherein the halide concentration is at least 9 M.
12. The method of claim 1 , wherein the hydrogen concentration is less than or equal to 5 M; and the halide concentration is at least 9 M.
13. The method of claim 1 , wherein the aqueous acid is continuously added.
14. The method of claim 13 , wherein the aqueous acid is continuously added at a rate to maintain an average hydrogen concentration greater than 0 M and less than or equal to 6 M.
15. The method of claim 1 , wherein the combination of the feedstock, the aqueous acid, and the halide salt further produces humins, levulinic acid, formic acid, furfural, gamma valerolactone, or fulvic acid, or any combinations thereof.
16. The method of claim 1 , wherein the feedstock, the aqueous acid, and the halide salt are further combined with solvent.
17. The method of claim 1 , wherein the 5-(halomethyl)furfural is produced at a temperature of at least 110° C.
18. The method of claim 1 , wherein the feedstock comprises glucose, fructose, sucrose, starch, inulin, cellulose, hemicellulose, cellulosic oligomers, or cellobiose, or any combinations thereof.
19. The method of claim 1 , wherein the feedstock is selected from the group consisting of corn stover, corn cob, corn kernel, rice flour, whole cane, beet pulp, beet processing raffinate, empty palm fruit bunches, palm fronds, saw dust, wood pellets, rice hulls, peanut hulls, spent grains, paper sludge, cardboard, old corrugated containers (OCC), old newspaper (ONP), mixed paper, wheat straw, paper mill effluent, newsprint, municipal solid wastes, wood chips, forest thinnings, slash, miscanthus , switchgrass, sorghum, bagasse, manure, wastewater biosolids, green waste, and food or feed processing residues, and any combinations thereof.
20. The method of claim 16 , wherein the solvent comprises one or more alkyl phenyl solvents, one or more heavy alkane solvents, one or more ester solvents, one or more aromatic solvents, one or more silicone oils, or any combinations or mixtures thereof.
21. The method of claim 2 , wherein the protic acid comprises nitric acid, phosphoric acid, sulfuric acid, fluoroboric acid, or any combination thereof.
22. The method of claim 7 , wherein the protic acid comprises nitric acid, phosphoric acid, sulfuric acid, or fluoroboric acid, or any combination thereof.