Citric acid

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Citric acid
Zitronensäure - Citric acid.svg
Citric-acid-3D-balls.png
Names
Preferred IUPAC name
2-Hydroxypropane-1,2,3-tricarboxylic acid
Other names
Citric acid
Identifiers
3D model (JSmol)
ChEBI
ChEMBL
ChemSpider
DrugBank
ECHA InfoCard 100.000.973
EC Number 201-069-1
E number E330 (antioxidants, ...)
KEGG
PubChem {{{value}}}
RTECS number GE7350000
UNII
SMILES {{{value}}}
Properties
C6H8O7
Molar mass 192.123 g/mol (anhydrous), 210.038 g/mol (monohydrate)CID 22230 from PubChem
Appearance crystalline white solid
Odor odorless
Density 1.665 g/cm3 (anhydrous)
1.542 g/cm3 (18 °C, monohydrate)
Melting point 156 °C (313 °F; 429 K)
Boiling point 310 °C (590 °F; 583 K) decomposes from 175 °C[1]
117.43 g/100 mL (10 °C)
147.76 g/100 mL (20 °C)
180.89 g/100 mL (30 °C)
220.19 g/100 mL (40 °C)
382.48 g/100 mL (80 °C)
547.79 g/100 mL (100 °C)[2]
Solubility soluble in acetone, alcohol, ether, ethyl acetate, DMSO
insoluble in C
6
H
6
, CHCl3, CS2, toluene[1]
Solubility in ethanol 62 g/100 g (25 °C)[1]
Solubility in amyl acetate 4.41 g/100 g (25 °C)[1]
Solubility in diethyl ether 1.05 g/100 g (25 °C)[1]
Solubility in 1,4-Dioxane 35.9 g/100 g (25 °C)[1]
log P −1.64
Acidity (pKa) pKa1 = 3.13
pKa2 = 4.76
pKa3 = 6.39,[3] 6.40[4]
1.493–1.509 (20 °C)[2]
1.46 (150 °C)[1]
Viscosity 6.5 cP (50% aq. sol.)[2]
Structure
Monoclinic
Thermochemistry
Std enthalpy of
formation
ΔfHo298
−1548.8 kJ/mol[2]
Std enthalpy of
combustion
ΔcHo298
−1960.6 kJ/mol[5]
−1972.34 kJ/mol (monohydrate)[2]
Standard molar
entropy
So298
252.1 J/(mol·K)[5]
Specific heat capacity, C 226.51 J/(mol·K) (26.85 °C)[5]
Pharmacology
A09AB04 (WHO)
Hazards
Main hazards skin and eye irritant
NFPA 704

NFPA 704.svg

1
2
0
 
Explosive limits 8%
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
☒N verify (what is ☑Y☒N ?)
Infobox references
Citric acid crystals, magnified about 200 times, seen through a polarizing filter.

Citric acid is a weak organic acid. It can be found in citrus fruits ( like oranges). It is used by organisms for Krebs cycle. It acts like a preservative when added to food. It is also used to add a sour (acidic) taste to foods and soft drinks. In the European Union it is known as E 330, as a food additive.

Carl Wilhelm Scheele was the first who could extract citric acid from lemons, in 1782. The substance was probably known to alchemists, perhaps with a different name. The Arabian alchemist Geber is said to have discovered citric acid in the 9th century. Citric Acid contains 6 Carbon atoms, 8 Hydrogen atoms and 7 Oxygen atoms. Its chemical formula is C6H8O7.

Main uses[change | change source]

References[change | change source]

  1. 1.0 1.1 1.2 1.3 1.4 1.5 1.6 "citric acid". chemister.ru.
  2. 2.0 2.1 2.2 2.3 2.4 CID 311 from PubChem
  3. "Data for Biochemical Research". ZirChrom Separations, Inc. Retrieved January 11, 2012.
  4. "Ionization Constants of Organic Acids". Michigan State University. Retrieved January 11, 2012.
  5. 5.0 5.1 5.2 Citric acid in Linstrom, Peter J.; Mallard, William G. (eds.); NIST Chemistry WebBook, NIST Standard Reference Database Number 69, National Institute of Standards and Technology, Gaithersburg (MD), http://webbook.nist.gov (retrieved 2014-06-02)

Other websites[change | change source]