Isopropyl Alcohol, (CH3)2CHOH, is based on Propane, and does not make you drunk, just dead. Ethyl Alcohol (also called Ethanol), C2H5OH, is based on Ethane. Denatured Alcohol is just Ethyl Alcohol which has poison added to stop people drinking it. This means it is cheaper as there is no tax to pay. Both are poisonous.