What Is Salicylaldehyde?
Salicylaldehyde is a clear, colorless liquid with an almond odor.
Salicylaldehyde has the chemical formula C7H6O2, molecular weight 122.12, and CAS number 90-02-8. Other names for salicylaldehyde include the IUPAC name 2-hydroxybenzaldehyde, o-formylphenol, and 2-hydroxybenzencarbaldehyde.
Salicylaldehyde is one of the isomers of hydroxybenzaldehyde, along with 3-hydroxybenzaldehyde and 4-hydroxybenzaldehyde, which have the ortho position of benzaldehyde replaced with a hydroxy group. Salicylaldehyde is an important precursor for a variety of chelating agents, some of which are commercially important.
Properties of Salicylaldehyde
Salicylaldehyde has a melting point of -7°C, a boiling point of 196-197°C, and a density of 1.17 g/cm3. The solubility of salicylaldehyde in solvents is 17.1 g/kg in water, which is not very soluble. In organic solvents, it is only slightly soluble in chloroform, miscible in ethanol, and readily soluble in acetone and benzene.
Salicylaldehyde has been identified as a characteristic odorant in buckwheat. It is also one of the components of the secretions from the scent sacs of mature North American and European beavers used in perfumes.
Uses of Salicylaldehyde
Salicylaldehyde is used as a synthetic raw material for a variety of chemicals. Oxidation with hydrogen peroxide in the dakin reaction yields catechol. Etherification with chloroacetic acid and cyclization can also yield benzofuran, a heterocyclic compound. Salicylaldehyde can also be condensed with amines to yield the chelating ligands salen and salicylaldoxime.
Salicylaldehyde is also used as a flavoring agent. It is used in small quantities in butter, caramel, nut, cinnamon, and fruit flavors.
Other Information on Salicylaldehyde
Process of Salicylaldehyde
Salicylaldehyde can be prepared from phenol and chloroform by heating with sodium hydroxide or potassium hydroxide in the Reimer-Tiemann reaction.
C6H5OH+CHCl3+3KOH→C6H4(OH)CHO+3KCl+2H2O
Alternatively, it can be produced by condensing phenol or its derivatives with formaldehyde to produce hydroxybenzyl alcohol, which is then oxidized to aldehyde.
Precautions for Handling and Storage
Precautions for handling and storage are as follows:
- Keep the container tightly closed and store in a cool, dark place out of direct sunlight.
- Keep away from flames and high temperatures due to the possibility of ignition.
- Due to its volatile nature, be careful not to inhale fumes or vapors.
- Hazardous incompatible materials include sodium chlorate, sodium perchlorate, hydrogen peroxide, sodium peroxide, ammonium nitrate, sodium nitrate, potassium permanganate, nitric acid, sulfuric acid, chromic anhydride, sodium chlorite, sodium bromate, potassium dichromate, etc. Therefore, take precautions when there is a possibility of contact with these substances.
- Use only outdoors or in well-ventilated areas.
- Wear protective gloves, protective glasses, protective clothing, and protective masks.
- Wash hands thoroughly after handling.
- In case of skin contact, wash with soap and water.
- In case of eye contact, rinse cautiously with water for several minutes.