Method for preparing sodium carboxymethyl cellulose

Abstract

The invention belongs to the field of natural polymer material chemical modification, and relates to a preparation method for high-substitution-degree and high-viscosity sodium carboxymethyl cellulose. The method comprises the following steps: taking and placing dried and smashed cellulose into a hydrothermal reaction kettle, adding an ethanol solution with a certain volume, dropwise adding1-3 ml of a 40% NaOH solution while stirring, and performing alkalization for 1-3 hours at 35 DEG C; after the alkalization is completed, adding sodium chloroacetate with the mass ratio of 1:(0.8-1.6), wherein the etherification temperature is 60-80 DEG C, and the etherification time is 1-3 h; after the reaction is completed, adjusting the pH value to be neutral by using glacial acetic acid, cooling to the room temperature, adding ethyl alcohol with 5 times of volume, stirring and dispersing for 10 min, performing suction filtration, washing with 90% ethyl alcohol for 3 times, finally, washing with ethyl alcohol for one time, and performing vacuum drying, so as to obtain the sodium carboxymethyl cellulose.

Description

Technical field: [0001] The invention belongs to the field of chemical modification of natural polymer materials, and relates to a preparation method of sodium carboxymethyl cellulose with high substitution degree and high viscosity. Background technique: [0002] Cellulose is a natural polymer compound, its chemical structure is a polysaccharide macromolecule based on anhydrous β-glucose, and there is one primary hydroxyl group and two secondary hydroxyl groups on each base ring. Through chemical modification, a series of cellulose derivatives can be obtained, and cellulose ether is one of them. Carboxymethylcellulose Sodium (CMC-Na) is an anionic, straight-chain, water-soluble cellulose ether. Its appearance is white or yellowish flocculent fiber powder, odorless, tasteless, and non-toxic. It can be widely used in medicine and health, daily chemical industry, papermaking, food, construction, materials and other industries, commonly known as "industrial monosodium glutamat...

AI Technical Summary

Problems solved by technology

[0003] At present, the sodium carboxymethylcellulose prepared by the traditional process in China is not easy to disperse in the aqueous solution, the dissolution rate is slow, and it takes a long time to stir to disperse and dissolve evenly.

Because the cellulose raw material will gelatinize and form micelles in a large amount of water, it is difficult for the etherification reagent to penetrate into the crystal region of the cellulose, resulting in insufficient reaction, and the resulting carboxymethylated product has a low degree of substitution and a large salt content. Strong alkaline, poor heat resistance and salt resistance