Ester is made from the esterization reaction of inorganic acid or organic acid or alcohol. Alcohol or phenol or acidic anhydride, alcohol and ethylene, free acidic acid and fatty nitrogen derivatives can also generate ester. The hydrogen on the alpha-carbon in the ester molecules loses a molecular alcohol with another molecular ester under alkaline conditions to generate β-keto ester, which is called ester contraction reaction. For example, acetyl acetate is generated to generate acetyl ethyl acetate. This reaction is extremely important in organic synthesis.

The name of the ester comes from the corresponding name of carboxylic acid and alcohol or phenol, such as "a certain acid and a certain ester". Circle esters are called lactone (lactone). The chemical properties of the ester are similar to the amyl niche anhydride, which is prone to hydrolysis, alcoholic and ammonia reaction. Low -grade ester is aromatic and volatile colorless liquid, and advanced ester is solid. Estes are important solvents and synthetic raw materials, and some esters are drugs themselves. According to the type of acid, ester can be divided into inorganic acid ester and organic acid ester. Etate, ethyl acetate is fatty ester, acetate is aromatic ester, and namanonate is a cyclic ester.