Production method for preparing low-substituted cellulose acetate

A technology of cellulose acetate and low degree of substitution, which is applied in the field of cellulose derivatives manufacturing, which can solve the problems of difficult industrialization, difficult production of cellulose acetate, and high cost of ionic liquids, and achieve the effect of reducing the degree of substitution of products

Inactive Publication Date: 2017-01-11
SICHUAN NITROCELLULOSE CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This method uses ionic liquids to prepare cellulose acetate and can directly synthesize cellulose acetate with a certain degree of substitution. However, the high cost of ionic liquids at this stage makes it difficult to realize industrialization
[0007] It is difficult for the above-mentioned prior art to achieve the goal of producing cellulose acetate with a degree of substitution of 1.6 to 2.0.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0028] A production method for preparing cellulose acetate with low degree of substitution, comprising the following steps:

[0029] (1) Selection of raw materials: use acetate grade refined cotton;

[0030] (2) Raw material pretreatment: put 200g of acetate-grade refined cotton in the activation machine, spray 600g of acetic acid on the acetate-grade refined cotton, and activate at room temperature for 1 hour;

[0031] (3) Esterification: Simultaneously mix 600g of acetic anhydride and 12g of concentrated sulfuric acid and cool to 0°C; put the activated cellulose acetate grade refined cotton into the cooled mixture for 20min, the reaction temperature is 40°C, and react for 1h;

[0032] (4) Hydrolysis: 550 g of acetic acid aqueous solution with a mass fraction of 50% was added to the solution after esterification, and hydrolyzed for 8 hours, so that the water content in the solution system was 13%;

[0033] (5) neutralization: adding 63g mass fraction to the hydrolyzate is 30...

Embodiment 2

[0037] A production method for preparing cellulose acetate with low degree of substitution, comprising the following steps:

[0038] (1) select raw material: select velvet wood pulp for use;

[0039] (2) Raw material pretreatment: put 200g fluffy wood pulp in the activation machine, spray 600g acetic acid on the cotton material, and activate it at room temperature for 1h;

[0040] (3) Esterification: Simultaneously mix 600g of acetic anhydride and 12g of concentrated sulfuric acid and cool to 0°C; put the activated cotton material into the cooled mixture for 30min, the reaction temperature is 50°C, and react for 0.5h;

[0041] (4) Hydrolysis: adding 550 g of acetic acid aqueous solution with a mass fraction of 50% to the esterification liquid, hydrolyzing for 8 hours, so that the water content in the solution system is 13%;

[0042] (5) neutralization: adding 63g mass fraction to the hydrolyzate is 30% sodium acetate aqueous solution, neutralizes the sulfuric acid of reaction...

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Abstract

The invention discloses a production method for preparing low-substituted cellulose acetate, comprising the main steps of (1) pretreating raw materials; (2) esterifying; (3) hydrolyzing; (4), neutralizing; (5) precipitating filtrate; (6) washing and drying. By modifying existing cellulose acetate production technology and optimizing based on heterogeneous process, the method for preparing high-viscosity low-substituted cellulose acetate is implemented; the low-substituted cellulose acetate prepared by the method has well lyophilic, is soluble in dilute acid solution, acetone and water mixture, is good in degradability and biocompatibility, and may serve as a good drug coating material, a drug auxiliary material and a drug taste covering material to the field of medicine.

Description

technical field [0001] The invention relates to a production method of cellulose acetate with a low degree of substitution, belonging to the technical field of cellulose derivative production Background technique [0002] Cellulose acetate (cellulose acetate for short), also known as cellulose acetate, is widely used in the manufacture of textiles, spray paint, coatings, plastics, cigarette filters, films and other fields. With the reduction of the degree of substitution of cellulose acetate, its hydrophilicity is enhanced, and its degradability and good biocompatibility as a cellulose derivative make it have many special uses. The cellulose acetate with a low degree of substitution of the present invention specifically refers to cellulose acetate with a degree of substitution of 1.6 to 2.0, which is soluble in dilute acid solution (35% acetic acid and 65% water) and in a mixed solvent of acetone and water (20% water with 80% acetone). Cellulose acetate with low degree of ...

Claims

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Application Information

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IPC IPC(8): C08B3/06
CPCC08B3/06
Inventor 阳洪鲁远翔杨洪袁满
Owner SICHUAN NITROCELLULOSE CORP
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