The raw materials of cellulose acetate can be divided into two categories: starting materials (substances used to manufacture cellulose acetate itself) and auxiliary materials (chemicals required in the production process).

Category 1: Starting materials (the cornerstone for manufacturing CDA)

1. Natural cellulose

Source: This is the most essential raw material, which is the skeleton of the polymer.

Cotton wool: Short fibers peeled from cottonseeds with extremely high alpha cellulose content (>95%), high purity, and uniform molecular weight. It is the preferred raw material for producing high-quality (especially medicinal and tobacco) cellulose acetate.

Wood pulp: Dissolved wood pulp derived from wood (usually coniferous trees) that has been highly refined and bleached. Its alpha cellulose content (usually>90%) and purity are slightly lower than cotton wool, but the cost is lower, making it the main raw material for large-scale industrial production (such as textiles and plastics).

2. Acetylation reagents

Acetic anhydride: This is a key acetylation reagent with a molecular structure of (CH3 CO) ₂ O. It reacts with hydroxyl groups (- OH) on cellulose molecules under the action of a catalyst, replacing hydrogen with acetyl groups (CH3 CO -) to form cellulose acetate.

Glacial acetic acid: serves as both a reaction medium (solvent) and participates in the reaction. It can form equilibrium with acetic anhydride and help control the reaction process and heat dissipation.

Category 2: Auxiliary raw materials (essential chemicals in the production process)

1. Catalyst

Concentrated sulfuric acid: the most commonly used catalyst. It can promote the reaction between acetic anhydride and cellulose, greatly improving the reaction speed and efficiency.

2. Hydrolyzing agent

Water/dilute acetic acid solution: Acetylation reaction yields cellulose triacetate (all hydroxyl groups are replaced). To obtain cellulose diacetate (about 74-92% of the hydroxyl groups are acetylated), a "hydrolysis" or "maturation" step must be performed. By adding a precisely controlled amount of water, some acetyl groups are broken, and triacetate cellulose is "partially saponified" into the desired diacetate cellulose.

3. Sedimentation and detergent

Water: Used to pour the reaction mixture into it to precipitate cellulose acetate from the solution.

Dilute acetic acid or sodium hydroxide solution: used to wash precipitated cellulose sheets or particles to neutralize and remove residual catalyst (sulfuric acid) and excess acetic acid.

4. Solvent (for subsequent processing)

Cellulose diacetate itself is a soluble plastic. According to the final use, it will be dissolved in specific solvents for processing:

Acetone: The most common solvent for cellulose acetate, used in the manufacture of cigarette filter filaments, textile fibers (acetate filaments), films, and plastics.

Organic solvent mixture: such as a mixture system of acetone ethanol water, commonly used for preparing pharmaceutical coating solutions.

Simply put, the core raw materials of cellulose diacetate are natural cellulose from plants and acetic anhydride from petrochemicals, which are produced through classic esterification hydrolysis chemical reactions.