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Direct synthesis of cellulose esters soluble in acetone and products thereof

A technology of cellulose ester and synthesis method, applied in the direction of artificial filament made of cellulose derivatives, etc., can solve problems such as limiting large-scale application, and achieve the effects of saving reaction time, reducing degradation reaction, and improving thermal stability

Active Publication Date: 2016-08-10
NANTONG CELLULOSE FIBERS CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0025] Trifluoroacetic acid is a good solvent for cellulose, and it dissolves quickly. Although it is expensive and corrosive, it is a potential solvent because of its low boiling point of 72-74°C, which is easy to recycle.
But this diacetate is insoluble in acetone, which greatly limits its large-scale application

Method used

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  • Direct synthesis of cellulose esters soluble in acetone and products thereof
  • Direct synthesis of cellulose esters soluble in acetone and products thereof
  • Direct synthesis of cellulose esters soluble in acetone and products thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0065] Put 3g (0.0185mol) cellulose acetate grade hardwood pulp and 150g trifluoroacetic acid into a three-neck flask with mechanical stirring, stir and infiltrate in an ice bath for 2-3 hours, then add 8.6g (0.0843mol) acetic anhydride until transparent state, kept at 50°C for 2 hours, finished the reaction by adding 30g of acetic acid, transferred to a rotary evaporator at 50°C for 1 hour, and finally precipitated the resulting product in a mixed solvent of acetic acid / water, washed with water, and dried to obtain 3.9g of white powder . The substituted acetic acid value (AV) of this product determined by titration method is 55.45%. through 1 The degree of substitution (DS) was determined to be 2.43 by H-NMR. The product is soluble in 91% / 9% dichloromethane / methanol, acetone, dimethylsulfoxide and pyridine.

[0066] The GPC figure of the product prepared by the method described in embodiment 1 and the cellulose diacetate prepared by usual industrial production is attached ...

Embodiment 2

[0072] Put 3 g of cellulose acetate grade hardwood pulp and 150 g of trifluoroacetic acid into a three-neck flask with mechanical stirring, stir and infiltrate in an ice bath for 2-3 hours, then add 8.94 g (0.0877 mol) of acetic anhydride to a transparent state, and keep for 50 After reacting at ℃ for 2 hours, 30 g of acetic acid was added to complete the reaction, and then transferred to a rotary evaporator at 50 °C for 1 hour. Finally, the resulting product was precipitated in an acetic acid / water mixed solvent, washed with water, and dried to obtain 4.3 g of a white powder product. After analysis, the acetic acid value (AV) of this product is 56.54%. 1 The degree of substitution (DS) was determined to be 2.51 by H-NMR. The product has been tested by GPC and FT-IR to prove that it does not contain sulfonate and trifluoroacetate groups. The product is soluble in 91% / 9% dichloromethane / methanol, acetone, dimethylsulfoxide and pyridine.

[0073] The cellulose diacetate produc...

Embodiment 3

[0075]Put 1.248g of acetate-grade hardwood pulp dried at 105°C for 1 hour, together with 49.95g of trifluoroacetic acid and 12.48g of dichloromethane, into a three-neck flask with mechanical stirring, stir and infiltrate in an ice bath overnight, and then add 3.35 g (0.033mol) acetic anhydride to a transparent state, keep the reaction at 50°C for 3 hours, add a small amount of dichloromethane to complete the reaction, transfer to a rotary evaporator and treat at 50°C for 1 hour, and finally precipitate the obtained product in hot water, wash with water, Drying yielded 1.8 g of the product as a white powder. After analysis, the acetic acid value (AV) of this product is 53.80%. 1 The degree of substitution (DS) of the product was determined to be 2.33 by H-NMR. The product has been tested by GPC and FT-IR to prove that it does not contain sulfonate and trifluoroacetate groups. The product is soluble in pyridine, dimethyl sulfoxide and acetone.

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Abstract

The present invention belongs to the field of organic polymer synthesis technology, and provides cellulose ester soluble in acetone and a direct synthesis process therefor. The synthesis process comprises the following steps: dissolving or partially dissolving a cellulose in a good solvent with a low boiling point with trifluoroacetic acid as the main ingredient, stirring and impregnating, and then adding an organic acid anhydride or an organic acid for an esterification reaction, recovering most of the good solvent having a low boiling point, subjecting the remaining solution to hydrolysis and precipitation to remove trifluoroacetic acid ester groups of the cellulose organic acid / trifluoroacetic acid mixed ester in the product, and precipitating to obtain the cellulose ester soluble in acetone. The cellulose ester made by the present invention has a degree of substitution of 2.2 to 2.6; furthermore, the cellulose ester has a high molecular weight, uniformly distributed ester groups, no sulphonic acid ester group in the macromolecules, and has a good physical mechanical strength and thermal stability. Cellulose esters of different degrees of substitution are prepared in the present invention by a direct synthesis process; this can save reaction time, reduce the amounts of the chemical reagents, and can also reduce the pollution to the environment caused by sulphates.

Description

technical field [0001] The invention belongs to the technical field of organic polymer synthesis, and relates to a direct synthesis method, product and application of acetone-soluble cellulose ester. Background technique [0002] At present, partially substituted cellulose esters are prepared industrially, such as cellulose diacetate (the degree of substitution DS is between 2.2 and 2..6), dipropionate, dibutyrate and their mixed diacid esters, Without exception, the cellulose (raw material is high-purity pulp) and the corresponding acid anhydride (acylating agent), acid (a non-good solvent in the initial stage of the reaction, and a good solvent in the later stage) and a catalyst (usually sulfuric acid) are used. Esterification is carried out to obtain cellulose tricarboxylate (substitution degree DS=3), and then the triester is hydrolyzed with water (or acid / water mixture) in a homogeneous system to obtain the required diacid. For example, the cellulose acetate obtained i...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C08B3/06C08B3/08C08B3/28C08B3/02D01F2/28C08L1/10
CPCC08B1/003C08B1/02C08B3/06C08B3/08C08B3/28C08L1/10C08L1/12
Inventor 王林富宋晓梅曹建国杨广美黄海建曹建华张杰
Owner NANTONG CELLULOSE FIBERS CO LTD
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