Angidrides

Angidrides are a class of chemical compounds derived from carboxylic acids. They are formed by the removal of a water molecule from two carboxylic acid molecules. The general formula for an anhydride of a monocarboxylic acid is (RCO)2O, where R represents an organic group. In the case of dicarboxylic acids, a single molecule of water can be removed to form a cyclic anhydride. For example, succinic acid can form succinic anhydride. Angidrides are typically less reactive than their corresponding acid chlorides but more reactive than esters. They are often used as acylating agents in organic synthesis, meaning they can introduce an acyl group (RCO-) into another molecule. This reaction commonly occurs with alcohols to form esters, or with amines to form amides. Angidrides can be hydrolyzed by water to regenerate the parent carboxylic acids. They are generally considered to be less volatile and less irritating than acid chlorides, making them a safer alternative in some synthetic procedures. The properties of angidrides vary depending on the nature of the organic groups attached.