Anhüdriidina

Anhüdriidina is the Finnish word for anhydride. In chemistry, an anhydride is a compound that can be formed from another compound, typically an acid, by the removal of one or more molecules of water. Acid anhydrides are often formed by the reaction of two molecules of a carboxylic acid with the loss of one molecule of water, or by the reaction of an acid chloride with a salt of a carboxylic acid.

Organic anhydrides are characterized by the presence of a functional group with the structure R-C(=O)-O-C(=O)-R', where R and R' are organic groups. These compounds are reactive and are often used as acylating agents, meaning they can introduce an acyl group (R-C(=O)-) into other molecules. For example, acetic anhydride is commonly used in the synthesis of aspirin.

Inorganic anhydrides are formed from inorganic acids or bases by the removal of water. For instance, sulfur trioxide is considered the anhydride of sulfuric acid. Metal oxides can also be considered anhydrides of metal hydroxides, though this is a less common usage. The term anhydride is also used more broadly to describe any compound from which water can be formally removed, even if the reaction is not practical or the compound is not directly synthesized in this way.