Cellulose acetate butyrate mixed ester with high butyryl content, and preparation method thereof

The invention discloses cellulose acetate butyrate mixed ester with high butyryl content, and a preparation method thereof. The cellulose ester is prepared from the following components in parts by weight: 600 parts of wood pulp, 800-1200 parts of butyric acid, 2500-3500 parts of butyric anhydride, 20-40 parts of acetic anhydride, and concentrated sulfuric acid catalyst accounting for 5-10% of total weight parts of wood pulp. The preparation method comprises the following steps: activating, performing esterification reaction, mixing, adding magnesium acetate solution, hydrolyzing, performing chromatography, and then sequentially conventionally filtering, washing and drying to obtain a finished product. According to cellulose acetate butyrate mixed ester with high butyryl content, cellulose acetate butyrate with the butyryl content of 48-53% and acetyl content of less than or equal to 4% can be obtained after the combination according to specific formula and proportion, and the product is stable in performances. The preparation method is simple in steps, the preparation period is short, the preparation conditions are not strict and easily achieved, and especially, the activated solid is fed into a cooling liquid within 2-5min, so that the quality of products can be guaranteed while the fast follow-up reaction is guaranteed.