Acetic acid, also called acetic acid (36%--38%), glacial acetic acid (98%), the chemical formula CH3COOH, is an organic monobasic acid, the main component of vinegar. Pure anhydrous acetic acid (glacial acetic acid) is a colorless, hygroscopic solid with a freezing point of 16.6°C (62°F). After solidification, it is colorless crystals. Its aqueous solution is weakly acidic and strongly corrosive. The steam is harmful to the eyes and nose Irritation.
Acetic acid is widely distributed in nature, for example in fruits or vegetable oils, but mainly exists in the form of esters. It exists in the form of free acids in animal tissues, excreta and blood. Many microorganisms can convert different organic matter to acetic acid through fermentation.