Hydrolysis of Cellulose Using an Acidic and Hydrophobic Ionic Liquid and Subsequent Separation of Glucose Aqueous Solution from the Ionic Liquid and 5-(Hydroxymethyl)furfural

Abstract

Cellulose was hydrolyzed using a novel biphasic system consisting of water and an acidic and hydrophobic ionic liquid. The biphasic system enabled a simple separation of the resulting glucose aqueous solution and ionic liquid. Additionally, a fermentation inhibitor, 5-(hydroxymethyl)furfural, could be removed from the aqueous phase into the ionic liquid phase. The yield of glucose in cellulose hydrolysis was 12.9% at 190 °C. The distribution ratio of glucose in the aqueous phase was 0.98 with an ionic liquid/water ratio of 0.13 (w/w), indicating that most of the glucose was recovered into the aqueous phase. 5-(Hydroxymethyl)furfural was absorbed into the ionic liquid phase from the aqueous phase. The concentration of 5-(hydroxymethyl)furfural in the aqueous phase decreased from 37 mM to 1.9 mM, which was lower than the concentration at which fermentation is inhibited (24 mM). The acidic and hydrophobic ionic liquids did not decompose during the cellulose hydrolysis and could be recycled four times.

Electrical Double Layer as a Model of Interaction between Cellulose and Solid Acid Catalysts of Hydrolysis

“…Ionic liquids attract research interest; one of their interesting features is the ability to break down the intermolecular hydrogen bonds in cellulose and dissolve it. Properties of ionic liquids can be widely varied: for example, they can serve as an acid catalyst or facilitate enzymatic hydrolysis …”

“…[8] Ionic liquids attract research interest; one of their interesting features is the ability to break down the intermolecular hydrogen bonds in cellulose and dissolve it. Properties of ionic liquids can be widely varied: for example, they can serve as an acid catalyst [9] or facilitate enzymatic hydrolysis. [10] In 2008, possibility of cellulose hydrolysis with solid catalysts (sulfonated or oxidized carbons, ion exchange resins, zeolites, acidic oxide catalysts) was demonstrated.…”

Ionic Liquids in Biomass Processing

“…In this study, Takahashi and co workers synthesized an acidic – hydrophobic IL comprising a long alkyl chain phosphonium cation and a HSO 4 − anion (trioctylpentylphosphonium hydrogensulfate) and performed the hydrolysis of cellulose. The recovery of glucose from the aqueous phase and separation of IL and HMF was possible by phase separation due to the significant polarity difference . The solvent extraction is another method under study for recovery of sugars from IL – biomass liquor .…”

“…The recovery of glucose from the aqueous phase and separation of IL and HMF was possible by phase separation due to the significant polarity difference. [222] The solvent extraction is another method under study for recovery of sugars from IL -biomass liquor. [223] This solvent extraction technique is based on the chemical affinity of boronates such as phenylboronic acid and naphthalene-2boronic acid for sugars; which was applied to the extraction of glucose, xylose, and cellobiose from an aqueous solution of 1ethyl-3-methylimidazolium acetate.…”

Efficient Hydrolysis of Lignocellulose by Acidic Ionic Liquids under Low-Toxic Condition to Microorganisms

“…Because of their remarkable capacity to delignify and solubilize cellulose, the ILs are often used for pretreating lignocellulosic biomass before hydrolysis [10][11][12][13][14][15]. On the other hand, Davis et al reported acidic ILs having an acidic group such as a sulfo group in their cationic and/or anionic structures [16][17][18][19][20], and the acidic ILs exhibit higher catalytic activity in cellulose hydrolysis compared to sulfuric acid [21].…”