Butanoic acid is a colorless, oily liquid with a strong, unpleasant odor often associated with rancid butter. It is a type of carboxylic acid, which means it contains a carboxyl group (-COOH) in its structure. Its chemical formula is C4H8O2, and it is commonly found in various natural sources, including animal fats and plant oils. This compound is used in the production of esters, which are important in the flavor and fragrance industries. Additionally, butanoic acid plays a role in the synthesis of various chemicals and can be found in some food products, contributing to their taste and aroma.