Cellulose acetate production method
If you want to make cellulose acetate, you first need to prepare raw materials. Cellulose has a wide source and is often taken from wood pulp, cotton lint and the like. These two are pure in texture and should be the starting choice.

Take an appropriate amount of cellulose and put it in the reactor. Then slowly inject acetic anhydride, which is the key reagent for acetylation. It is necessary to measure accurately. The ratio of acetic anhydride to cellulose should be carefully considered according to the degree of substitution of the desired product.

Add the raw material and a catalyst to promote the reaction. Sulfuric acid is often used, but its dosage should be used with caution. A small amount of sulfuric acid can be highly catalyzed, and a large amount may cause a cluster of side reactions and damage the product.

In the reactor, the temperature is controlled to an appropriate extent. Usually between 60 and 80 degrees Celsius, the temperature is too high or cellulose degradation is caused, and if it is too low, the reaction is slow and time-consuming. Maintain a constant temperature to make the reaction uniform and stable.

During the reaction, stir is often added to make the material fully mixed. Uniform mixing can synchronize all parts of the reaction, avoiding the risk of local over-reaction or insufficient reaction.

After several reactions, observe its progress. Sampling and analysis can be used to measure the degree of acetyl substitution by infrared spectroscopy, nuclear magnetic resonance, etc., to show the degree of reaction. When the desired degree of substitution is reached, the reaction stops.

The subsequent process is separation and purification. The reaction liquid is poured into a precipitant, such as methanol, ethanol, etc., and cellulose acetate is then precipitated. The precipitate is filtered and washed several times with alcohols, except for unreacted raw materials, catalysts and by-products.

The washed precipitate is placed in an oven and dried at controlled temperature. The temperature should not be high to prevent the product from being thermally decomposed. After its constant weight and cellulose acetate is finished, a high-quality finished product can be obtained for various applications.