PROCESS TO PREPARE LEVULINIC ACID
The invention describes processes to prepare levulinic acid, formic acid and/or hydroxymethyl furfural from various biomass materials.
1 . A process to prepare levulinic acid comprising the steps:
a) heating an aqueous solution of a mineral acid to a temperature from about 60° C. to about 160° C. in a reactor, wherein the mineral acid is present from at least 20 percent by to about 80 percent by weight; and
b) adding from about 0.15 pounds to about 80 pounds per hour of a monosaccharide or di-saccharide per 100 pounds of the heated aqueous acid in the reactor to form a reaction mixture, to provide levulinic acid.
2 . The process of claim 1 , further comprising the step of combining the reaction mixture comprising levulinic acid with a phenolic or substituted phenolic extraction solvent to create an extraction phase and an aqueous raffinate phase, wherein levulinic acid and optionally, formic acid are in the extraction phase.
3 . The process of claim 2 , wherein the phenolic or substituted phenolic extraction solvent is a phenol, an alkylphenol, a xylenol, a methoxyphenol, a cresol, a polydimethylsiloxane, a substituted alkyl phenol, a tertiary amine/alkyl phenol mixture, phenol/alkyl phenol blends with a C5-C36 hydrocarbon or C6-C12 aromatic hydrocarbons, 2-ethyl-hexanoic acid or perfluoro-octanoic acid or perfluoro-octanol or mixtures thereof.
4 . The process of claim 3 , wherein the extraction solvent comprises phenol, 4-methoxyphenol, 2-methoxyphenol, 3-methoxyphenol, 2-sec-butyl phenol, 3-sec-butyl phenol, 4-sec-butyl phenol, 2-t-butyl phenol, 4-t-butyl phenol, 2,4-di-t-butyl phenol, 2,4-di-methoxyphenol, 2-methylphenol, 3-methylphenol, 4-methylphenol, 2,3-xylenol, 2,4-xylenol, 2,5-xylenol, 2,6-xylenol, 3,4-xylenol, or 3,5-xylenol, 4-hexyl-resorcinol, butylated hydroxyl-toluene (BHT), 2,5-dimethoxyphenol, 3,5-dimethoxy phenol, 2,6-dimethoxy phenol, nonylphenol, or mixtures thereof.
5 . The process of claim 2 , further comprising the step of subjecting the extraction phase to a base, an anion exchange resin, or water washing the extraction phase to reduce the amount of mineral acid present to less than or equal to 0.5 weight percent of the extraction phase.
6 . The process of claim 2 , further comprising the step of treating the aqueous raffinate phase with an adsorbent, such as activated carbon or with a hydrocarbon solvent to decrease the amount of the extraction solvent from the raffinate phase.