Method for removing straw lignin and hemicellulose by using protic ionic liquid

Abstract

The invention discloses a method for removing straw lignin and hemicellulose by using single ionic liquid and by a one-step method. The ionic liquid in the method is polyhydroxyl protic ammonium salt ionic liquid. The method is characterized in that three components of a lignocellulose material are dissolved and separated under the conditions that the temperature is 80 to 160 DEG C, the time is 0.25 to 24 hours and the mass percentage of the lignocellulose material is 5 to 10 percent, so that the lignin content and the hemicellulose content can be reduced by 50 to 95 percent simultaneously. The ionic liquid is characterized in that the used synthetic raw materials are cheap and simple in synthesis method, and have biodegradability; the lignin and the hemicellulose are dissolved and removed from the biomass component simultaneously by the ionic liquid one-step method, a cellulose I type material with the purity higher than 70 percent is obtained, and the crystal structure of the cellulose in the raw material biomass component is maintained. By the method, the problems that the conventional ionic liquid is expensive and has poor separation effect are solved, possibility is provided for industrialization of pretreating biomass by the ionic liquid, and the ionic liquid belongs to a novel biomass pretreatment solvent.

Description

technical field [0001] The invention relates to a polyhydroxy proton type ammonium salt ionic liquid which dissolves and separates cellulose, lignin and hemicellulose in lignocellulose straw raw materials to obtain high-purity cellulose type I materials, belonging to the field of biomass. Background technique [0002] With the depletion of fossil resources on the earth, energy and environmental issues have become important problems that need to be solved in the development of human industrialization. The development and use of green renewable resources and the efficient use of resources are effective ways to solve the current slow development of the chemical industry. Biomass resources, as a green renewable energy with large reserves and wide distribution on the earth, have received extensive attention in research and exploration in recent years. In addition to forest vegetation, crop stalks and various annual plant stalks also play an important role in the material and ener...

AI Technical Summary

Problems solved by technology

[0005] The cations used for the dissolution of biomass components in ionic liquids mainly include N-methylimidazoles, ammonium salts and phosphorus salts, and the anions are mainly X - (halogen), CH 3 COO - 、CH 3 SO 4 - , (CH 3 ) 2 o 2 PO 2 - and HCO 2 - etc. However, most single ionic liquids cannot achieve efficient separation of cellulose and hemicellulose in lignocellulosic components, and the synthesis steps are more, the cost is high, and the cellulose material obtained by dissolving and regenerating will destroy the cellulose in the raw material. The crystal structure of the compound is limited in the subsequent application. At the same time, the use of dimethyl sulfoxide organic solvent in the dissolution and separation causes serious environmental pollution and does not conform to the concept of sustainable development and green process engineering.

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