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Modification method of lignin

A lignin modification technology, applied in the field of lignin, can solve the problems of high process requirements, achieve the effects of improving reactivity, facilitating commercialization, and facilitating packaging and transportation

Inactive Publication Date: 2011-11-23
INST OF CHEM IND OF FOREST PROD CHINESE ACAD OF FORESTRY
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  • Abstract
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  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] In order to solve the problems of using high-pressure equipment and high process requirements in existing lignin demethylation experiments, the present invention provides a lignin modification method, which performs demethylation reaction at normal pressure and lower temperature to obtain The lignin is in powder form, which improves the reactivity with formaldehyde, and can replace phenol to prepare thermoplastic phenolic resin and thermosetting phenolic resin

Method used

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Experimental program
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Effect test

Embodiment 1

[0031] Lignosulfonate: sodium hydroxide: n-dodecanethiol: dimethylformamide (mass ratio) is 1:0.2:1:5. Stir n-dodecanethiol, a part of dimethylformamide and sodium hydroxide at room temperature for 20 minutes, dissolve lignosulfonate in the remaining solvent, stir for 10 minutes, add the solution containing lignosulfonate To the mixture containing n-dodecanethiol and sodium hydroxide. Oil bath at 130°C, reacted for 3h under nitrogen protection. After the reaction is completed, add water to dilute and add acid to adjust the pH to 2, centrifuge to obtain demethylated lignin, dry at room temperature, wash with n-hexane, filter, and dry at room temperature again to obtain demethylated lignin.

[0032]

Embodiment 2

[0034] Lignosulfonate: sodium hydroxide: n-dodecanethiol: ethyl acetate (mass ratio) is 1:0.3:1:5. Stir n-dodecanethiol, a part of dimethylformamide and sodium methoxide at room temperature for 20 minutes, dissolve the lignosulfonate in the remaining ethyl acetate solvent, stir for 10 minutes, and dissolve the solution containing lignosulfonate Added to the mixture containing n-dodecanethiol and sodium methoxide. Oil bath at 100°C, under nitrogen protection, react for 1h. After the reaction is completed, add water to dilute and add acid to adjust the pH to 2, centrifuge to obtain demethylated lignin, dry at room temperature, wash with n-hexane, filter, and dry at room temperature again to obtain demethylated lignin.

[0035] The organic solvent used is any one of dimethylformamide, ethyl acetate, dioxane, pyridine or methanol or any mixture of any several

Embodiment 3

[0037]Alkali lignin: potassium tert-butoxide: n-decamercaptan: methanol (mass ratio) is 1:0.6:1.5:5. Stir n-decathiol, a part of dimethylformamide and sodium methoxide at room temperature for 20 minutes, dissolve the alkali lignin in the remaining solvent, stir for 10 minutes, add the solution containing n-decathiol and methanol sodium mixture. Oil bath at 120°C, reacted for 1.5h under nitrogen protection. After the reaction is completed, add water to dilute and add acid to adjust the pH to 2, centrifuge to obtain demethylated lignin, dry at room temperature, wash with n-hexane, filter, and dry at room temperature again to obtain demethylated lignin.

[0038]

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Abstract

The invention relates to a modification method of lignin. The modification method comprises: adding and dissolving lignin in an organic solvent in which a thiol and a basic catalyst are dissolved, carrying out a demethylation reaction, centrifuging, washing and drying to obtain pure demethylated lignin, wherein the mass ratio of lignin to the catalyst to the thiol to dimethyl formamide is 1: (0.2-0.6): (0.5-2): (5-10). The lignin provided by the invention has the advantages that the free radicals are not polymerized in the modification process, the molecular weight of the lignin is reduced and the polarity is simultaneously improved, the reaction activity with formaldehyde is improved, and the lignin can replace phenol at a high ratio. The lignin modified by the modification method is in a shape of powder, can be used for preparing thermoplastic phenolic resins and thermosetting phenolic resins, and can also be used for adhesives, phenolic foam plastics, polyurethane foam plastics, phenolic molding materials, carbonization functional materials, polyurethane films and other multiple novel polymer materials.

Description

technical field [0001] The invention relates to the field of lignin, in particular to a method for modifying lignin. Background technique [0002] Lignin is a natural polyphenolic compound widely present in plants. In nature, lignin is regenerated at a rate of 50 billion tons per year, and the pulp and paper industry separates 140 million tons of cellulose from plants every year, and at the same time obtains 50 million tons of lignin by-products. The pollution of lignin to the environment mainly exists in papermaking wastewater. In foreign countries, wood is used to make paper, and the papermaking waste liquid is recovered by alkali, and the lignin is burned into heat energy at the same time, so the papermaking waste liquid will not pollute the environment. In my country, however, wheat straw, rice straw, reed and bagasse are the main papermakers, which are difficult to recover alkali and seriously pollute the environment. Therefore, no matter from resource utilization or...

Claims

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Application Information

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IPC IPC(8): C08H7/00C08G16/02
Inventor 周永红胡立红潘晖张猛
Owner INST OF CHEM IND OF FOREST PROD CHINESE ACAD OF FORESTRY
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