Methyl salicylate

 

Methyl salicylate
aka oil of wintergreen

Chemical formula	C8H8O3
Molar Mass(g/mol)	152
Density(g/cc)	1.174
Melting Point(°C)	-9
Boiling Point(°C)	220
Solubility in water(g/L)	0.639
Solubility in ethanol(g/L)	soluble
NFPA 704	1 2 0

Uses

• Pleasant minty smell & taste.
• Trivially broken down into two useful chemicals: methanol and phenol:

Natural occurrence

• Many plants produce this material biologically, including betula lenta, gaultheria procumbens, salix alba, and filipendula ulmaria

Hazards

• 7-10g taken orally is fatal for adults. 4g for children.

Production

Extraction

Steam distillation

• Methyl salicylate is produced by maceration and steam distillation of the leaves of wintergreens such as Gaultheria procumbens or the bark of betula lenta, with the heavier oil removed via a dean-stark trap, and the water returned to the still.

Solvent extraction

• Methyl salicylate may be leached from the leaves of Teaberry or the twigs of sweet birch by ethanol.

Synthesis

• Fischer Esterifying methanol with salicylic acid over sulfuric acid gives methyl salicylate

  CH₃OH + C₇H₆O₃

  {H₂SO₄

  →

  }

  C₈H₈O₃ + H₂O

Purification

• Wintergreen oil is soluble in diethyl ether but not in water. A liq/liq extraction would remove water soluble impurities.

See Also

Documents

• Kennedy, George W. (1882) "Oleum Betulae Lentae"
  American Journal of Pharmacy 56 
  link courtesy Henrietta's Herbal.

Publications

• Power, By Prof Dr Frederick B (1890) "ON THE COMPOSITION OF THE OILS WINTERGREEN AND BIRCH AND THE CHARACTERS OF THE SYNTHETIC OIL OF WINTERGREEN"
  The Chemical News and Journal of Physical Science 62 Edwin John Davy, London.
  link courtesy Google Books.