Acid chlorides, also known as acyl chlorides, are organic compounds derived from carboxylic acids. They contain a carbonyl group (C=O) bonded to a chlorine atom. Acid chlorides are typically reactive and are used in various chemical reactions, including the synthesis of esters and amides. These compounds are often produced by reacting carboxylic acids with thionyl chloride or phosphorus pentachloride. Due to their reactivity, acid chlorides can easily undergo hydrolysis, forming the corresponding carboxylic acid. They are important intermediates in organic synthesis and are widely used in the production of pharmaceuticals and agrochemicals.