Citric acid

Citric acid is a weak organic acid wi the formula C6H8O7. It is a naitural preservative/conservative an is an aa uised tae add an acidic or sour taste tae fuids an drinks. In biochemistry, the conjugate base o citric acid, citrate, is important as an intermediate in the citric acid cycle, which occurs in the metabolism o aw aerobic organisms.

Citric acid
Citric acid
Names
IUPAC name
2-hydroxypropane-1,2,3-tricarboxylic acid
Ither names
3-carboxy-3-hydroxypentanedioic acid
2-hydroxy-1,2,3-propanetricarboxylic acid[1]
Identifiers
CAS Nummer
3D model (JSmol)
ChEBI
ChEMBL
ChemSpider
DrugBank
EC Nummer201-069-1
KEGG
RTECS nummerGE7350000
UNII
Properties
C6H8O7
Molar mass192.124 g/mol (anhydrous)
210.14 g/mol (monohydrate)
Appearancecrystalline white solid
Odourodorless
Density1.665 g/cm3(1.5g/cm3 for monohydrate)
Meltin pynt 156 °C (313 °F; 429 K)
Bylin pynt 310 °C (590 °F; 583 K)
Solubility in watter
59[2] g/100 ml (20 °C)
Solubilityvery soluble in ethanol
soluble in ether, ethyl acetate
insoluble in benzene, chloroform
log P-1.64
Acidity (pKa)pKa1 = 3.14
pKa2 = 4.75
pKa3 = 6.39,[3] 6.40[4]
Thermochemistry
Std enthalpy o
formation ΔfHo298
-1548.8 kJ/mol
Hazards
Main hazardsskin an eye irritant
NFPA 704
NFPA 704 four-colored diamondFlammability code 1: Must be pre-heatit afore igneetion can occur. Flash pynt ower 93 °C (200 °F). E.g., canola ileHealth code 2: Intense or continued but nae chronic exposure could cause temporary incapacitation or possible residual injury. E.g., chloroformReactivity code 0: Normally stable, even unner fire exposur condeetions, an is nae reactive wi watter. E.g., liquid nitrogenSpecial hazards (white): no code
1
2
0
Flash pynt155 °C (311 °F)
Explosive leemits1.8-4.8%
Lethal dose or concentration (LD, LC):
LD50 (Median dose)
3000 mg/kg (rat, oral)
Relatit compoonds
Except whaur itherwise notit, data are gien for materials in thair staundart state (at 25 °C [77 °F], 100 kPa).
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Infobox references

Citric acid is a commodity chemical, an mair nor a million tonnes are produced every year bi fermentation. It is uised mainly as an acidifier, as a flavorin, an as a chelatin agent.

References