Dehydration of ethanol produces ethene. During the reaction, a molecule of water is eliminated from ethanol, and the remaining atoms combine to form ethene. This is an example of an elimination reaction, where a small molecule is removed from a larger molecule to form a new product. The reaction is typically carried out at high temperatures in the presence of a catalyst such as concentrated sulfuric acid or alumina. Ethene is an important industrial chemical that is used as a feedstock for the production of many other organic chemicals.