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.
The ester is generally a neutral colorless liquid. The ester generated by the fatty race and saturated alcohol has a fruit aroma, which can be dissolved in water, and it is also difficult to dissolve in water. Some ester's flash point is low and often burn. The steam can be absorbed by the respiratory tract, and the liquid ester can be absorbed by the skin. After absorption, it is dissolved in the plasma, and some of them are discharged through the lungs and kidneys. After some hydrolysis, turn into the normal metabolic process. In addition to a few of the ester compounds, most of them are highly toxic and highly toxicity, and most of them are micro -toxic to medium toxic categories, and many of them are non -toxic. There are 38 esters in the aroma groups of tea. Mainly: ① fatty ester: generated by alcohol and fat, such as ethyl acetate, hexyl hexyate. ② Aromatic ester: generated by alcohol and aromatic acid, such as Shun-3-hexylzyl. ③ Circin esters: generated by alcohol and cyclocar, such as jasmone hyacxide. The ester is generally neutral, which can be hydrolyzed and produces alcohol and acid. Low carbon numbers are usually fragrant liquids, and high carbon numbers are liquid and solids insoluble in water.