Preparation method of carboxylated lignin

A technology of lignin and carboxylation, which is applied in the field of low-carbon preparation of new materials and the recycling and reuse of renewable resources, can solve the problems of restricting, reducing the market demand of lignin-based low-efficiency water reducers, and high cost

Inactive Publication Date: 2010-09-08
BEIJING GHEMU TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

With the development of the construction industry and technological progress, more high-efficiency and cheap water-reducing agent products have come out, such as polycondensate, naphthalene sulfonate, melamine and internal maintenance-type water-reducing agents. The limitation of functional groups and molecular structure, and the poor compoundability of these high-efficiency water reducers reduce the market demand for lignin-based low-efficiency water reducers and increase the development of industries related to lignin (such as the paper industry) Difficulty restricts the development of related circular economy models, especially restricts the development of a healthy circular economy model for the p...

Method used

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  • Preparation method of carboxylated lignin
  • Preparation method of carboxylated lignin
  • Preparation method of carboxylated lignin

Examples

Experimental program
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Effect test

Embodiment 1

[0024] The amount of catalyst in the reaction is 5.0wt.% of the total amount of lignin, containing Fe 2+ (Iron acetylacetonate), Cu 2+ (Schiff base copper), and Nd 3+ (Neodymium acetate) salt, molar ratio Fe 2+ / Cu 2+ / Nd 3+ =6 / 4 / 0.5, dissolved in 30wt% lignin aqueous solution. The reaction pressure is 0.02MPa, the reaction temperature is 90°C, and the reaction time is 2 hours. The experimental results show that the carboxyl (-COOH) content of the product has increased by 8×10 -3 mol / g, compared with the original lignin, the molecular weight distribution curve measured by GPC moved to the high molecular weight end, from 20,000 to 40,000 of the original lignin, and the molecular weight distribution narrowed, and the peak half-maximum width (HWFM) from 30,000 dropped to 21,000.

Embodiment 2

[0026] The amount of catalyst in the reaction is 3.0wt.% of the total lignin, containing Sn 4+ (tin octoate), Ti 4+ (titanium naphthenate), and Po 3+ (Po(iPrCp)) salt with a molar ratio of Sn 4+ / Ti 4+ / Po 3+ =4 / 1 / 0.5, dissolved in 20wt% lignin aqueous solution. The reaction pressure is 0.3 MPa, the reaction temperature is 110° C., and the reaction time is 30 minutes. The experimental results show that the carboxyl (-COOH) content of the product has increased by 6×10 -3 mol / g, compared with the original lignin, the molecular weight distribution curve measured by GPC moved to the high molecular weight end, from 20,000 to 30,000 of the original lignin, and the molecular weight distribution narrowed, and the peak half-maximum width (HWFM) from 30,000 dropped to 25,000.

Embodiment 3

[0028] The amount of catalyst in the reaction is 3.0wt.% of the total amount of lignin, containing V 4+ (vanadium acetate), Zr 4+ (zirconium naphthenate), and Er 3+ (Erbium acetylacetonate) salt, the molar ratio is V 4+ / Zr 4+ / Er 3+ =5 / 1 / 2, dissolved in 10wt% lignin aqueous solution. The reaction pressure is 0.5 MPa, the reaction temperature is 140° C., and the reaction time is 4 hours. The experimental results show that the carboxyl (-COOH) content of the product has increased by 20×10 -3 mol / g, compared with the original lignin, the molecular weight distribution curve measured by GPC moves to the end of high molecular weight and low molecular weight, from 20,000 to 10,000 of the original lignin, and the molecular weight distribution becomes narrower, and the peak half-maximum width (HWFM ) from 30,000 to 10,000.

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Abstract

The invention relates to a preparation method of carboxylated lignin, belonging to the fields of new low-carbon preparation technology of new materials and cyclic reutilization of renewable resources. The method of the invention comprises the following steps: pressing air into an air distributor in a reaction kettle by utilizing an air compressor; fully and uniformly mixing the air with lignin liquor under the condition of stirring; and under the aid of a composite catalyst, reacting at 50-140 DEG C under 0.02-1.0MPa for 30-480 minutes to obtain the carboxylated lignin, wherein the dosage of the composite catalyst is 0.01-5.0wt.% of the dry weight of the lignin; the composite catalyst at least contains more than one transition metal salt and at least contains one rare earth metal salt, and the mol ratio range of the transition metal salt to the rare earth element salt is 3:1-20:1; and the number of the air distributor is at least one, and the air distributor is a plurality of perforated pipes the pore diameter of which gradually increases from top to bottom and the pore number of which gradually decreases. The invention can carry out reasonable adjustment and control on molecular chains, chain structures and functional groups thereon of the lignin and reduce the cost.

Description

technical field [0001] The invention relates to a method for preparing carboxylated lignin by using transition metal salts and rare earth metal salts as catalysts and using air as an oxygen source to catalyze oxidation and controllable preparation of carboxylated lignin. . Background technique [0002] With the shortage of petroleum resources, the use of renewable biomass to prepare fuels and chemicals has become a current research hotspot. Plant biomass is an important part of biological resources, and its main components include cellulose, hemicellulose and wood. white. Among them, lignin is the most abundant renewable natural polymer after cellulose, and its main structural units are syringylpropane, guaiacylpropane and p-hydroxyphenylpropane. At present, lignin, as a non-fibrous compound, is mainly turned into industrial waste (such as black liquor in the paper industry), which is discarded and causes deep environmental pollution, which has become a difficult problem f...

Claims

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Application Information

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IPC IPC(8): C08H6/00C08H7/00
Inventor 宋玉军
Owner BEIJING GHEMU TECH
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