Two general mechanisms are known for deacetylation. One mechanism involves zinc binding to the acetyl oxygen. Another family of deacetylases require NAD+, which transfers an ribosyl group to the acetyl oxygen.[1]
Acetate esters[5] andacetamides[6] are generally prepared by acetylations. Acetylations are often used in making C-acetyl bonds inFriedel-Crafts reactions.[7][8] Carbanions and their equivalents are susceptible to acetylations.[9]
Cellulose is apolyol and thus susceptible to acetylation, which is achieved using acetic anhydride. Acetylation disrupts hydrogen bonding, which otherwise dominates the properties of cellulose. Consequently, the cellulose esters are soluble in organic solvents and can be cast into fibers and films.[12]
Acetylation of wood is a chemical modification process that enhances the properties of wood by making it highly resistant to fungi and insects, as well as very durable against moisture and environmental parameters.[13][14]
The process involves the chemical reaction ofacetic anhydride with the free hydroxyl groups in wood polymers, mostly of lignin and hemicelluloses, without requiring a catalyst. The modification results in bonds between the structural polymeric components, significantly reducing the ability of the -OH groups to form hydrogen bonds with water molecules. This effectively "locks" the cellular walls, minimizing the capacity of wood to absorb water and enhancing its dimensional stability. Approximately 80-90% of the hydroxyl groups of wood are modified during the process. The whole process is an environmentally friendly treatment, and has emerged, in the 21st century, as a significant innovation in the scientific area ofwood science.[10][15]
Transacetylation usesvinyl acetate as an acetyl donor andlipase as a catalyst. This methodology allows the preparation of enantio-enriched alcohols and acetates.[16]
