Ascorbic acid

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Ascorbic acid
Ascorbic acid bottle and sample.jpg
L(+) ascorbic acid sample and original bottle
L-Ascorbic acid structure.png
The structure of ascorbic acid.
Names
IUPAC name
(2R)-2-[(1S)-1,2-dihydroxyethyl]-3,4-dihydroxy-2H-furan-5-one
Other names
Ascoltin
Ascorbate
Ascorbic acid
L-ascorbic acid
Vitamin C
Properties
C6H8O6
Molar mass 176.12 g/mol
Appearance White solid
Odor Odorless
Density 1.694 g/cm3
Melting point 190 °C (374 °F; 463 K)
Boiling point 192 °C (378 °F; 465 K) (decomposes)
30 g/100 ml (at 20 °C)
40 g/100 ml (at 40 °C)
Solubility Slightly soluble in alcohols
Insoluble in benzene, chloroform, dichloromethane, diethyl ether, petroleum ether, toluene, xylene, oils, lipids
Solubility in ethanol 3.3 g/100 ml
Solubility in ethanol 95 % 2 g/100 ml
Solubility in glycerol 1 g/100 ml
Solubility in propylene glycol 5 g/100 ml
Vapor pressure 9.28·10-11 mmHg (25 °C)
Hazards
Safety data sheet Sigma-Aldrich
Lethal dose or concentration (LD, LC):
11,900 mg/kg (rat, oral)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Ascorbic acid is a naturally-occurring organic compound more routinely known as vitamin C. It is found naturally in many fruits and is a well-known antioxidant. It can be easily purchased in tablet or powder form in groceries or pharmacies. In the field of chemistry, it is used as a reducing agent, such as in the precipitation of elemental copper from a solution of copper(II) ions, as well as a means of introducing the ascorbate ion.

Properties

Chemical

Ascorbic acid can be used to reduce silver nitrate to metallic silver.

It will also reduce hexavalent chromium to Cr(III).

Physical

Ascorbic acid is a white to light yellow solid, soluble in water, with a sour taste. It is soluble in water, less so in alcohols, glycerol, propylene glycol, and insoluble in benzene, chloroform, diethyl ether, petroleum ether, as well as fats and oils.

Availability

Ascorbic acid is sold in pharmacies an most food stores, usually in the form of pills. It is also sometimes sold in the winemaking sections of stores, in bulk quantities.

Preparation and isolation

Ascorbic acid is much cheaper to be extracted from fruits than synthesized from precursors. However, one will need large amounts of fruits or other plant material to get any useful amounts of ascorbic acid. Even extracting it from fruits that are very rich in vitamin C, like kakadu plums, acerola, seabuckthorn or the more common rose hips, requires a significant amount of said fruits.

Extraction from vitamin C supplements is easier, especially since vitamin supplements are usually cheap.

Projects

  • Reduce various metals compounds to their respective metals
  • Destroy Cr(VI) ions
  • Vitamin C (food-grade only!)

Handling

Safety

Ascorbic acid is vital to the organism. Lack of ascorbic acid leads to scurvy.

Ascorbic acid has very low toxicity, but excess consumption may cause indigestion or diarrhea.

Storage

Ascorbic acid should be kept in closed bottles.

Disposal

Ascorbic acid can be safely poured down the drain, dumped in trash, soil or just burned, as it is practically non-toxic.

References

Relevant Sciencemadness threads