Citric acid

The Citric acid, also known as 1,2,3-Propanetricarboxylic acid, 2-hydroxy-, is the organic compound with the formula C₆H₈O₇. Citric acid is a weak organic acid which is a white crystalline powder. Its EINECS registry number is 201-069-1. With the CAS registry number 77-92-9, its IUPAC name is 2-hydroxypropane-1,2,3-tricarboxylic acid.It is stable but incompatible with bases, strong oxidizing agents, reducing agents, metal nitrates. Reactions with metal nitrates are potentially explosive. Heating to the point of decomposition causes emission of acrid smoke and fumes. Citric acid can exist either in an anhydrous (water-free) form or as a monohydrate. Citric acid is soluble in water.

Physical properties of Citric acid:
(1)ACD/BCF (pH 5.5): 1; (2)ACD/BCF (pH 7.4): 1; (3)ACD/KOC (pH 5.5): 1; (4)ACD/KOC (pH 7.4): 1; (5)#H bond acceptors: 7; (6)#H bond donors: 4; (7)#Freely Rotating Bonds: 6; (8)Index of Refraction: 1.575; (9)Molar Refractivity: 36.04 cm³; (10)Molar Volume: 109.007 cm³; (11)Surface Tension: 103.956 dyne/cm; (12)Density: 1.762 g/cm³; (13)Flash Point: 155.243 °C; (14)Enthalpy of Vaporization: 63.816 kJ/mol; (15)Boiling Point: 309.567 °C at 760 mmHg; (16)Vapour Pressure: 0 mmHg at 25 °C.

Preparation of Citric acid:
Except for small amounts produced from citrus-fruit wastes, Citric acid is manufactured by aerobic fermentation of crude sugar or com sugar by a special strain of Aspergillus niger. The submerged process for the manufacture of it involves coordinated sequences of biochemical conversions with the aid of A. niger and various unit operations and chemical conversions.
C₁₂H₂₂O₁₁ + H₂O + 3O₂ → 2C₆H₈O₇ + 4H₂O
 sucrose                         citric acid
2C₆H₁₂O₆ + 3O₂ → C₆H₈O₇ + 4H₂O
 dextrose              citric acid

Uses of Citric acid:
Citric acid is a natural preservative/conservative and is also used to add an acidic, or sour, taste to foods and soft drinks. It is used mainly as an acidifier, as a flavoring, and as a chelating agent. Citric acid can also be used in food coloring to balance the pH level of a normally basic dye. As a food additive, Citric acid is used as a flavoring and preservative in food and beverages, especially soft drinks. Citric acid may be used as the main ripening agent in the first steps of making mozzarella cheese. Citric acid is used as a successful alternative to nitric acid in passivation of stainless steel. Citric acid can be used as a lower-odor stop bath as part of the process for developing photographic film.Citric acid is also used to remove fatty acids in blood vessels and to lower blood pressure. Meanwhile, it can also be used for cleaning, for example, Citric acid's ability to chelate metals makes it useful in soaps and laundry detergents and Citric acid can be used in shampoo to wash out wax and coloring from the hair. In addition, Citric acid can be used in cosmetics and pharmaceuticals, which is commonly used as a buffer to increase the solubility of brown heroin and as one of the active ingredients in the production of antiviral tissues.

Safety information of Citric acid:
When you are using this chemical, please be cautious about it as the following:This chemical may cause inflammation to the skin or other mucous membranes. It is irritating to eyes, respiratory system and skin. In case of contact with eyes, you should rinse immediately with plenty of water and seek medical advice. Whenever you will contact it, please wear suitable protective clothing, gloves and eye/face protection.

You can still convert the following datas into molecular structure:
(1)InChI: InChI=1S/C6H8O7/c7-3(8)1-6(13,5(11)12)2-4(9)10/h13H,1-2H2,(H,7,8)(H,9,10)(H,11,12)
(2)InChIKey: KRKNYBCHXYNGOX-UHFFFAOYSA-N
(3)Canonical SMILES: C(C(=O)O)C(CC(=O)O)(C(=O)O)O

The toxicity data of Citric acid is as follows: