Preparation method of low-propionyl-content cellulose acetate propionate mixed ester

Abstract

The invention relates to a preparation method of low-propionyl-content cellulose acetate propionate mixed ester. Cellulose is prepared from, by weight, 650 g of wood pulp, 296 g of propionic acid, 2250 g of acetic acid, 118 g of acetic anhydride, 2070 g of propionic anhydride and 19.5-52 g of catalysts. The ratio of liquid acid catalysts to heteropolyacid catalyst is between 4 to 6 and 6 to 4. The preparation method includes the steps of conducting activating, the esterification reaction, mixing, magnesium acetate solution adding, hydrolysis and chromatography, sequentially conducting conventional filtering, washing and drying, and obtaining the finished product. The method has the advantages that the propionyl content of the obtained cellulose acetate propionate finished product is 15-20%, and the acetyl content is smaller than 22-30%; the mixture of liquid acid and heteropolyacid is selected for the catalysts, and therefore the sulfuric acid consumption is lowered, the corrosion to a technological device and the pollution to the environment can be reduced, and technological safety is improved; meanwhile, by adding heteropolyacid, the esterification reaction is accelerated, and the hydrolysis reaction is more precise and controllable.

Description

technical field [0001] The invention belongs to the field of cellulose lipid derivatives, in particular to a kind of high propionyl content [0002] The preparation method of cellulose acetate propionate mixed ester. Background technique [0003] Cellulose acetate propionate (CAP for short) is a cellulose organic acid ester prepared by esterification of cellulose, acetic anhydride and propionic anhydride. CAP has excellent toughness, thermal stability and compatibility, and is widely used in auto parts, tool handles, radio and TV parts, steering wheels, films, filters, radio transistors, toys, wall and floor tiles, coatings, spinning and other industries . [0004] At present, the content of propionyl group in the domestic production of cellulose acetate propionate is relatively unstable, and the Chinese patent application number is: 201110009701.8 patent discloses a kind of preparation method of cellulose acetate propionate, this method is raw material with cellulose, wit...

AI Technical Summary

Problems solved by technology

The cellulose acetate butyrate butyryl content that this method prepares is higher, but there are following problems: 1. use the concentrated sulfuric acid as catalyzer in this preparation method, process equipment is had very strong corrosion, and use the concentrated sulfuric acid in a large amount, It will pollute the environment; 2. The esterification reaction time is long, and the hydrolysis reaction control is not precise enough; 3. The reaction stage needs to be cooled by an external jacket, which makes the production cost higher

[0006] In addition, cellulose acetate propionate mixed esters with low propionyl content are currently used in some specific chemical fields, but it is rare to produce cellulose acetate propionate mixed esters with low propionyl content