Phenol

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Phenol
Phenol

Phenol in 3D Phenol's potential surface

Systematic name Phenol
Other names Carbolic Acid
Benzenol
Phenylic Acid
Hydroxybenzene
Chemical formula C6H5OH
SMILES OC1=CC=CC=C1
Molar mass 94.11 g/mol
Appearance White Crystalline Solid
CAS number [108-95-2]
Properties
Density 1.07 g/cm3
Solubility in water 8.3 g/100 ml (20 °C)
Melting point 40.5 °C
Boiling point 181.7 °C
Acidity (pKa) 9.95
Structure
Molecular shape planar
Dipole moment  ? D
Hazards
MSDS External MSDS
EU classification Toxic (T)
Muta. Cat. 3
Corrosive (C)
NFPA 704

2
4
0
 
R-phrases R23/24/25, R34,
R48/23/24/25, R68
S-phrases S1/2, S24/25, S26,
S28, S36/37/39, S45
Flash point 79 °C
Autoignition temperature 715 °C
RTECS number SJ3325000
Supplementary data page
Structure and
properties
n, εr, etc.
Thermodynamic
data
Phase behaviour
Solid, liquid, gas
Spectral data UV, IR, NMR, MS
Related compounds
Related compounds Benzenethiol
Disclaimer and references

Phenol, also known under an older name of carbolic acid, is a colourless crystalline solid with a typical sweet tarry odor. Its chemical formula is C6H5OH and its structure is that of a hydroxyl group (-OH) bonded to a phenyl ring; it is thus an aromatic compound.

[edit] Phenols

Main article: phenols

The word phenol is also used to refer to any compound which contains a six-membered aromatic ring, bonded directly to a hydroxyl group (-OH). In effect, phenols are a class of organic compounds of which the phenol discussed in this article is the simplest member.

[edit] Properties

Phenol has a limited solubility in water (8.3 g/100 ml). It is slightly acidic: the phenol molecule has weak tendencies to lose the H+ ion from the hydroxyl group, resulting in the highly water-soluble phenoxide anion C6H5O. Compared to aliphatic alcohols, phenol shows much higher acidity; it even reacts with NaOH to lose H+ whereas aliphatic alcohols do not. This is due to orbital overlap between the oxygen's lone pairs and the aromatic system, which delocalizes the negative charge throughout the ring and stabilizes the anion. This effect is attenuated, however, due to oxygen's relatively high electronegativity. [1]

[edit] Production

Phenol can be made from the partial oxidation of benzene or benzoic acid, by the cumene process, or by the Raschig process. It can also be found as a product of coal oxidation.

[edit] Uses

Phenol has antiseptic properties, and was used by Sir Joseph Lister in his pioneering technique of antiseptic surgery, though the skin irritation caused by continual exposure to phenol eventually led to the substitution of aseptic (germ-free) techniques in surgery. It is one of the main components of the commercial antiseptic TCP (trichlorophenol). It is also the active ingredient in some oral anesthetics such as Chloraseptic spray.

It is also used in the production of drugs (it is the starting material in the industrial production of aspirin), weedkiller, and synthetic resins (Bakelite, one of the first synthetic resins to be manufactured, is a polymer of phenol with formaldehyde). Exposure of the skin to concentrated phenol solutions causes chemical burns which may be severe; in laboratories where it is used, it is usually recommended that polyethylene glycol solution is kept available for washing off splashes. Washing with large amounts of plain water (most labs have a safety shower or eye-wash) and removal of contaminated clothing are required, and immediate ER treatment for large splashes; particularly if the phenol is mixed with chloroform (a commonly used mixture in molecular biology for DNA purification). Notwithstanding the effects of concentrated solutions, it is also used in cosmetic surgery as an exfoliant, to remove layers of dead skin. It is also used in phenolization, a surgical procedure used to treat an ingrown nail, in which it is applied to the toe to prevent regrowth of nails.

Injections of phenol have occasionally been used as a means of rapid execution.

Phenol was also used as a means of extermination by the Nazis during the Second World War. Phenol injections were given to thousands of people in concentration camps, especially at Auschwitz-Birkenau. Injections were administered either by medical doctors or by their assistants; such injections were originally given intravenously, more commonly in the arm, but injection directly into the heart, so as to induce nearly instant death, was later preferred. [2]

Phenols are extremely harmful to cats. [3]

[edit] See also

[edit] References

  1. ^ The Acidity of Phenol. ChemGuide. Jim Clark. Retrieved on 2006-10-28.
  2. ^ Killing through phenol injection. Auschwitz - FINAL STATION EXTERMINATION. Johannes Kepler University, Linz, Austria. Retrieved on 2006-09-29.
  3. ^ Poison - hidden dangers?. Information for cat owners. Feline Advisory Bureau. Retrieved on 2006-09-29.

[edit] External links