The physical and chemical properties of citric acid
Citric acid, is a tricarboxylic acid, its scientific name is 3-hydroxy-3-carboxyglutaric acid, and its molecular formula is C6H8O7 (anhydrous). It exists in lemons in nature , Citrus, plum, plum, pear, peach, fig and other fruits.
Citric acid is non-toxic, colorless, and odorless. It is generally translucent crystals or white powder. It is easily soluble in water, ethanol, acetonitrile, ether, etc., insoluble in benzene, but slightly soluble in chloroform. The relative density is 1.542g/cm3, and the melting point is 153°C (water loss).
The crystalline form of citric acid varies with different crystallization conditions. There are anhydrous citric acid and citric acid containing crystal water. Slightly weathering in dry air, deliquescent in humid air, and liberate water and carbon dioxide above 175°C. Citric acid is a strong organic acid with 3 H+ that can be ionized; the aqueous solution is acidic and can be decomposed into a variety of products when heated, and reacts with acids, alkalis, glycerol, etc.
Uses of citric acid
Citric acid has a pleasant sour taste, is refreshing in the mouth, has no aftertaste, is safe and non-toxic, and is widely used as a sour agent for food and beverages; it can form complexes with divalent or trivalent cations and is used for metal processing Chelating agents and detergents (detergency supplements that soften water); can also be derived to form many derivatives, which can be used as raw materials for the organic chemical industry.
Therefore, it is widely used in the fields of food and beverage, medicine and chemical industry, cleaning and cosmetics, organic materials, etc. It is currently the most in demand organic acid in the world. Up to now, there is no sour agent that can replace citric acid.