The formation of acetals (acetylation) is a chemical reaction in which acetal is produced. It can occur in various ways, with the formation from aldehydes being particularly well-known. This reaction is a true equilibrium reaction, meaning that the equilibrium can lie far to the right or far to the left. The position of the equilibrium can be altered by manipulating the reaction conditions. The water produced can be continuously removed from the reaction mixture, for example, through distillation, or the alcohol can be added in excess.