Natural citric acid is widely distributed in nature. Natural citric acid is found in the bones, muscles and blood of fruits such as lemons, citrus, pineapples, and plants such as animals. Synthetic citric acid is fermented from sugar, molasses, starch, grapes and other sugary substances.
Many fruits and vegetables, especially citrus fruits, contain high levels of citric acid, especially lemons and limes—they contain significant amounts of citric acid, up to 8% when dried (the amount found in juice). about 47 g/l. In citrus fruits, the content of citric acid is between 0.005 mol/L for oranges and grapes and 0.30 mol/L for lemons and limes. This content varies with the growth of different varieties and plants.
The difference between citric acid anhydrous and citric acid monohydrate：
1. Different application fields:
Citric acid monohydrate is mainly used in the food and beverage industry as a sour agent, flavoring agent, preservative, and preservative. It is also used as antioxidant, plasticizer, detergent in chemical industry, cosmetic industry and washing industry. Anhydrous citric acid is mainly used in the food and beverage industry as a sour agent, acidity regulator, flavoring agent, preservative, and preservative.
Anhydrous citric acid is widely used in the national economy, and many industrial sectors require anhydrous citric acid. The sector that uses the most anhydrous citric acid is the manufacture of chemicals, followed by the manufacture of paper, aluminum, tungsten, rayon, rayon and soap. In addition, in the production of dyes, plastics, pharmaceuticals and organic intermediates, the regeneration of old rubber, the production of sodium metal, the electrolysis of water and the production of inorganic salts, the production of borax, chromium salts, manganates, phosphates, etc., should also be used. Plenty of anhydrous citric acid. At the same time, anhydrous citric acid is one of the important raw materials for the production of polycarbonate, superabsorbent polymer, zeolite, epoxy resin, sodium phosphate, sodium sulfite and a large number of sodium salts.
2.Different chemical properties:
Citric acid monohydrate may cause combustion and explosion when exposed to open fire, high heat or contact with oxidants, while anhydrous citric acid has weathering properties in dry air and deliquescence in humid air, above 175°C Decomposition releases water and carbon dioxide.
3.Different molecular weights:
The molecular weight of citric acid monohydrate is 581, while the molecular weight of anhydrous citric acid is 420.
4.Different physical properties:
The relative density of citric acid monohydrate is 1.542, the melting point is 153 °C, the refractive index is 1.493~1.509, and the critical temperature of solution crystallization is 36.6 °C. And anhydrous citric acid properties: density 1.54, melting point 135-152 ℃, flash point 173.9 ℃, water solubility 1630 g/L.
