Microcrystalline cellulose and method for preparing microcrystalline cellulose using crop straw

Abstract

The invention discloses a microcrystalline cellulose and a method for preparing the microcrystalline cellulose by using crop straws. Separation and extraction of straw crude cellulose with a high boiling point organic solvent, the obtained crude cellulose is partially hydrolyzed under the action of a spherical solid acid catalyst, and the resulting hydrolyzed mixture is left to stand, filtered, solid is collected, and dried to obtain a spherical solid acid catalyst and micro The solid mixture of crystalline cellulose is further sieved to recover the solid catalyst and obtain microcrystalline cellulose with a degree of polymerization ranging from 156 to 402. The microcrystalline cellulose prepared by the present invention has high purity and moderate degree of polymerization, and can be used as a fine chemical raw material. The high boiling point solvent used has low volatility and good thermal stability and can be recovered through simple extraction operations. The solid acid catalyst has high catalytic activity and is easy to separate and recover, which overcomes the problems of pollution and corrosion caused by the low boiling point solvent volatilization and the use of strong inorganic acid in traditional methods.

Description

technical field

[0001] The invention belongs to the field of resources and environment, and specifically relates to the high-value utilization of agricultural waste resources, and more specifically, to a microcrystalline cellulose and a method for preparing microcrystalline cellulose by using crop straws. Background technique

[0002] Crop straw is a valuable renewable biomass resource. According to the report of the United Nations Environment Programme, the crops planted in the world can provide about 2 billion tons of various straws every year. China's straw output ranks first in the world, with an annual production of about 700 million tons of straw, and my country's straw output alone can be converted into 353 million tons of standard coal. With the continuous deterioration of the environment and the increasing scarcity of fossil resources and wood resources, the development of comprehensive utilization of renewable resources has become one of the effective ways to deal ...

Examples

Embodiment 1

[0036] Add the mixed solvent of wheat straw powder, N-methylpyrrolidone and water (the volume ratio of N-methylpyrrolidone and water is 1:2), sulfuric acid (so that the concentration in the solution is 0.05M) into the autoclave , wherein the weight ratio of wheat straw powder and mixed solvent is 1:6, heated to 180°C, stirred for 4h, cooled to room temperature, centrifuged and suction filtered to obtain filtrate and solid product. The solid product was washed with the same above-mentioned mixed solvent, the washing liquid and the filtrate were combined, the filtrate was extracted with chloroform, and the organic solvent was recovered. The solid product is wheat straw crude cellulose with a purity of 75.3%. Put the wheat straw crude cellulose into the round bottom flask, and then add the prepared mixed solution containing 4wt% sodium carbonate and 2wt% hydrogen peroxide. The weight ratio of the wheat straw crude cellulose to the mixed solution is 1:7.5.70 Heat and stir at ℃ fo...

Embodiment 2

[0038]Add the mixed solvent of wheat straw powder, N-methylpyrrolidone and water (the volume ratio of N-methylpyrrolidone and water is 1:1), sulfuric acid (so that the concentration in the solution is 0.03M) into the autoclave , wherein the weight ratio of wheat straw powder and mixed solvent is 1:8, heated to 190°C, stirred for 6h, cooled to room temperature, centrifuged, and suction filtered to obtain filtrate and solid product. The solid product was washed with the same above-mentioned mixed solvent, the washing liquid and the filtrate were combined, the filtrate was extracted with chloroform, and the organic solvent was recovered. The solid product is wheat straw crude cellulose with a purity of 79.7%. Put the wheat straw crude cellulose into the round bottom flask, and then add the prepared mixed solution containing 4wt% sodium carbonate and 2wt% hydrogen peroxide. The weight ratio of the wheat straw crude cellulose to the mixed solution is 1:7.5.70 Heat and stir at ℃ fo...

Embodiment 3

[0040] Add the mixed solvent of wheat straw powder, N-methylpyrrolidone and water (the volume ratio of N-methylpyrrolidone and water is 1:1), sulfuric acid (so that the concentration in the solution is 0.03M) into the autoclave , wherein the weight ratio of wheat straw powder and mixed solvent is 1:8, heated to 190°C, stirred for 6h, cooled to room temperature, centrifuged, and suction filtered to obtain filtrate and solid product. The solid product was washed with the same above-mentioned mixed solvent, the washing liquid and the filtrate were combined, the filtrate was extracted with chloroform, and the organic solvent was recovered. The solid product is wheat straw crude cellulose with a purity of 79.7%. Put the wheat straw crude cellulose into the round bottom flask, and then add the prepared mixed solution containing 6wt% sodium carbonate and 1wt% hydrogen peroxide. The weight ratio of the wheat straw crude cellulose to the mixed solution is 1:7.5.60 Heat and stir at ℃ f...

technical field

[0001] The invention belongs to the field of resources and environment, and specifically relates to the high-value utilization of agricultural waste resources, and more specifically, to a microcrystalline cellulose and a method for preparing microcrystalline cellulose by using crop straws. Background technique

[0002] Crop straw is a valuable renewable biomass resource. According to the report of the United Nations Environment Programme, the crops planted in the world can provide about 2 billion tons of various straws every year. China's straw output ranks first in the world, with an annual production of about 700 million tons of straw, and my country's straw output alone can be converted into 353 million tons of standard coal. With the continuous deterioration of the environment and the increasing scarcity of fossil resources and wood resources, the development of comprehensive utilization of renewable resources has become one of the effective ways to deal ...

Examples

Embodiment 1

[0036] Add the mixed solvent of wheat straw powder, N-methylpyrrolidone and water (the volume ratio of N-methylpyrrolidone and water is 1:2), sulfuric acid (so that the concentration in the solution is 0.05M) into the autoclave , wherein the weight ratio of wheat straw powder and mixed solvent is 1:6, heated to 180°C, stirred for 4h, cooled to room temperature, centrifuged and suction filtered to obtain filtrate and solid product. The solid product was washed with the same above-mentioned mixed solvent, the washing liquid and the filtrate were combined, the filtrate was extracted with chloroform, and the organic solvent was recovered. The solid product is wheat straw crude cellulose with a purity of 75.3%. Put the wheat straw crude cellulose into the round bottom flask, and then add the prepared mixed solution containing 4wt% sodium carbonate and 2wt% hydrogen peroxide. The weight ratio of the wheat straw crude cellulose to the mixed solution is 1:7.5.70 Heat and stir at ℃ fo...

Embodiment 2

[0038]Add the mixed solvent of wheat straw powder, N-methylpyrrolidone and water (the volume ratio of N-methylpyrrolidone and water is 1:1), sulfuric acid (so that the concentration in the solution is 0.03M) into the autoclave , wherein the weight ratio of wheat straw powder and mixed solvent is 1:8, heated to 190°C, stirred for 6h, cooled to room temperature, centrifuged, and suction filtered to obtain filtrate and solid product. The solid product was washed with the same above-mentioned mixed solvent, the washing liquid and the filtrate were combined, the filtrate was extracted with chloroform, and the organic solvent was recovered. The solid product is wheat straw crude cellulose with a purity of 79.7%. Put the wheat straw crude cellulose into the round bottom flask, and then add the prepared mixed solution containing 4wt% sodium carbonate and 2wt% hydrogen peroxide. The weight ratio of the wheat straw crude cellulose to the mixed solution is 1:7.5.70 Heat and stir at ℃ fo...

Embodiment 3

[0040] Add the mixed solvent of wheat straw powder, N-methylpyrrolidone and water (the volume ratio of N-methylpyrrolidone and water is 1:1), sulfuric acid (so that the concentration in the solution is 0.03M) into the autoclave , wherein the weight ratio of wheat straw powder and mixed solvent is 1:8, heated to 190°C, stirred for 6h, cooled to room temperature, centrifuged, and suction filtered to obtain filtrate and solid product. The solid product was washed with the same above-mentioned mixed solvent, the washing liquid and the filtrate were combined, the filtrate was extracted with chloroform, and the organic solvent was recovered. The solid product is wheat straw crude cellulose with a purity of 79.7%. Put the wheat straw crude cellulose into the round bottom flask, and then add the prepared mixed solution containing 6wt% sodium carbonate and 1wt% hydrogen peroxide. The weight ratio of the wheat straw crude cellulose to the mixed solution is 1:7.5.60 Heat and stir at ℃ f...