Method for separating lignin and cellulose from lignocellulose by using ionic liquid solvent

Abstract

The invention relates to a method for separating lignin and cellulose from lignocellulose by using ionic liquid solvent, which comprises the following steps: adopting ionic liquid synthesized from an imidazole compound and halogenated alkane and water to form a liquid phase system which is added with wood flour, wood chips or vegetation plants to separate the lignin and the cellulose in a high-pressure autoclave at certain pressure and temperature, wherein the lignin is dissolved in ionic liquid water solution; filtering, separating, cleaning and drying the solid phase to obtain a cellulose product; and diluting, filtering, separating and drying the liquid phase to obtain a lignin product, wherein the ionic liquid can be recycled. The method achieves the separation of the lignin and the cellulose, the prepared cellulose product can be used as a raw material for papermaking directly and also can be used for preparing cellulose derivatives applied to the fields of daily use chemicals, medicaments, biology and the like; and the lignin can be used for preparing lignin modified products. The method does not volatile organic solvents and causes no environmental pollution, the used solvent can be recycled, and the production cost is low, thus the method has strong industrial application prospect.

Description

technical field [0001] The invention belongs to the application field of chemical industry, and in particular relates to a process for separating lignin and cellulose in plant raw materials by using an ionic liquid solvent. Background technique [0002] With the increasingly severe oil crisis and environmental pollution, the country has increasingly strict requirements on the production process of chemical raw materials, and more and more attention has been paid to the development and utilization of renewable biomass resources. Cellulose and lignin, the main components of agricultural crops and forestry residues, are the most abundant renewable biomass resources on Earth. my country is a large agricultural country. The national crop straw output is about 600 million tons per year, of which about 300 million tons of cellulose can be collected and used per year. At present, the method of separating lignin from cellulose in papermaking and other industries will produce a large...

AI Technical Summary

Problems solved by technology

At present, the method of separating lignin from cellulose in papermaking and other industries will produce a large amount of red liquor and black liquor, causing serious environmental pollution

According to statistics, the total amount of pulping in China in 2002 was close to 20 million tons, and the annual output of black (red) liquid was nearly 200 million tons. The main organic component in these black (red) liquids, namely lignin, can reach more than 5 million tons, a large Part of it pollutes the environment with the discharge of papermaking wastewater, and the recycled part is in addition to direct combustion treatment. The annual output of industrial lignin products (mainly lignosulfonate) is less than 500,000 tons. Except for some directly used as concrete water reducers, a large amount Research and development of valuable lignin resources is poor

[0003] More or less volatile organic solvents are used in the existing lignin separation methods, causing certain environmental pollution

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