1. General principle of CMC production
(1) Consumption quota (solvent method, calculated per ton of product): cotton linters, 62.5kg; ethanol, 317.2kg; alkali (44.8%), 11.1kg; monochloroacetic acid, 35.4kg; toluene, 310.2kg,
(2) Production principle and method? Alkaline cellulose is made from cellulose and sodium hydroxide aqueous solution or sodium hydroxide aqueous ethanol solution, and then reacted with monochloroacetic acid or sodium monochloroacetate to obtain a crude product, and the alkaline product is dried , Pulverized into commercially available carboxymethyl cellulose (sodium salt vine). The crude product is then neutralized, washed, and sodium chloride removed, then dried and crushed to obtain refined sodium carboxymethyl cellulose. The chemical formula is as follows:
(C6H9O4-OH)4+nNaOH-(C6H9O4-ONa)n+nH2O
(3) Process description
The cellulose is crushed and suspended in ethanol, add lye with 30rain under constant stirring, keep at 28-32°C, cool down to a low temperature, add monochloroacetic acid, heat up to 55°C for 1.5h and react for 4h; add acetic acid to neutralize the reaction mixture , The crude product is obtained by separating the solvent, and the crude product is washed twice with methanol liquid in the washing equipment composed of a mixer and a centrifuge, and dried to obtain the product.
CMC solution has high viscosity, and temperature change will not cause gelation.
2. The production process of ultra-high viscosity sodium carboxymethyl cellulose
A production process of ultra-high viscosity sodium carboxymethyl cellulose.
step:
(1) Put cellulose, alkali and ethanol into the alkalization kneader in proportion to carry out alkalization under the protection of nitrogen, and then put in etherifying agent chloroacetic acid ethanol solution to initially etherify the materials;
(2) Transport the above materials into the etherification kneader to control the temperature and reaction time for etherification reaction, and transport the materials to the washing tank after the etherification reaction is completed;
(3) Wash the etherification reaction material with dilute ethanol solution to remove the salt generated by the reaction, so that the purity of the product can reach more than 99.5%;
(4) Then the material is subjected to centrifugal pressing, and the solid material is transported to the stripper, and the ethanol solvent is extracted from the material through the stripper;
(5) The material passed through the stripper enters the vibrating fluidized bed for drying to remove excess water, and then crushes to obtain the product. The advantage is that the process is perfect, the product quality index can reach the viscosity of 1% B type > 10000mpa.s, and the purity > 99.5%.
Carboxymethyl cellulose is a derivative with ether structure obtained by chemical modification of natural cellulose. The carboxyl group on the molecular chain can form a salt. The most common salt is sodium salt, namely sodium carboxymethyl cellulose (Na -CMC), customarily called CMC, is an ionic ether. CMC is a high fluidity powder, white or light yellow in appearance, tasteless, odorless, non-toxic, non-flammable, non-mildew, and stable to light and heat.