Treating biomass to produce materials useful for biofuels
Fermentable sugar useful for the production of biofuels can be produced from biomass by contacting the biomass with a solution containing at least one α-hydroxysulfonic acid. The α-hydroxysulfonic acid can be easily removed from the product and recycled.
1. A composition comprising
(a) biomass containing polysaccharides;
(b) at least one α-hydroxysulfonic acid;
(c) water; and
(d) at least one fermentable sugar
wherein the α-hydroxysulfonic acid is present in an amount of from 1% wt. to about 55% wt. based on the composition; and
wherein the α-hydroxysulfonic acid is produced from (a) a carbonyl compound with (b) sulfur dioxide or a precursor to sulfur dioxide and (c) water.
2. The composition of claim 1 wherein the α-hydroxysulfonic acid has a general formula
wherein R 1 and R 2 are individually hydrogen or hydrocarbyl with up to about 9 carbon atoms that may or may not contain oxygen atoms.
3. The composition of claim 2 wherein the α-hydroxysulfonic acid is a mixture of compounds with the general formula.
4. The composition of claim 1 wherein the α-hydroxysulfonic acid has a general formula
wherein R 1 and R 2 are individually hydrogen or hydrocarbyl with up to about 9 carbon atoms that may or may not contain oxygen atoms.
5. The composition of claim 4 wherein the α-hydroxysulfonic acid is a mixture of compounds with the general formula.
6. The composition of claim 1 wherein the carbonyl compound or a precursor to the carbonyl compound is selected from the group consisting of formaldehyde, acetaldehyde, propionaldehyde, n-butyraldehyde, i-butyraldehyde, glycolaldehyde, glyceraldehyde, glyoxal, furfural, salicylaldehyde, benzaldehyde, acetone, acetol, methyl ethyl ketone, mesityl oxide, methyl i-butyl ketone, cyclohexanone, chloroacetone, trioxane, paraformaldehyde, alcohols having 1 to 7 carbon atoms, hydroxyacetaldehyde, and mixtures thereof.
7. The composition of claim 1 wherein the α-hydroxysulfonic acid is present in equilibrium with its component form.
8. The composition of claim 7 wherein the equilibrium with its component form is present as
wherein R 1 and R 2 are individually hydrogen or hydrocarbyl with up to about 9 carbon atoms or a mixture thereof.
9. The composition of claim 1 wherein the α-hydroxysulfonic acid is selected from the group consisting of α-hydroxyethane sulfonic acid, α-hydroxymethane sulfonic acid, bis-α-hydroxymethane sulfonic acid, and mixtures thereof.