The methyl salicylate is a chemical, an organic nature, considered the most toxic compound known among salicylates, despite its colorless appearance and pleasant odor with sweet light touch. This species is better known by the name wintergreen oil. Its formula is C 8 H 8 O 3.
It is in a liquid state under standard conditions of temperature and pressure (25 ° C and 1 atm), constituting an organic ester that occurs naturally in a wide variety of plants . From the observation and study of its production in nature, it was possible to proceed to the synthesis of methyl salicylate.
This synthesis was carried out by means of a chemical reaction between the ester from salicylic acid and its combination with methanol. In this way, this compound is part of sage, white wine, and fruits such as plums and apples, among others found naturally.
Synthetically, methyl salicylate is used in the production of flavoring agents, as well as in certain foods and beverages.
The chemical structure of methyl salicylate is made up of two main functional groups (an ester and a phenol attached to it), as shown in the image above.
It is observed that it is constituted by a benzene ring (which represents a direct influence on the reactivity and stability of the compound), coming from the salicylic acid from which it is derived.
To name them separately, it can be said that a hydroxyl group and a methyl ester are attached in the ortho (1,2) position to the aforementioned ring.
Then, as the OH group is attached to the benzene ring, a phenol is formed, but the group that has the highest “hierarchy” in this molecule is the ester, giving this compound a particular structure and, therefore, quite specific characteristics.
In this way, its chemical name is presented as methyl 2-hydroxybenzoate, granted by the IUPAC although it is used less frequently when referring to this compound.
– It is a chemical species that belongs to the group of salicylates, which are products of natural origin from the metabolism of some plant organisms.
– The therapeutic properties of salicylates in medical treatments are known.
– This compound is present in certain beverages such as white wine, tea, sage and certain fruits such as papaya or cherry.
– It is found naturally in the leaves of a large number of plants, especially in certain families.
– It belongs to the group of organic esters that can be synthesized in the laboratory.
– It is obtained in a liquid state, whose density is approximately 1,174 g / ml under standard conditions of pressure and temperature (1 atm and 25 ° C).
– It forms a colorless, yellowish or reddish liquid phase, considered soluble in water (which is an inorganic solvent) and in other organic solvents.
– Its boiling point is approximately 222 ° C, manifesting its thermal decomposition around 340 to 350 ° C.
– It has multiple applications, ranging from flavoring agent in the candy industry to analgesic and other products in the pharmaceutical industry.
– Its molecular formula is represented as C 8 H 8 O 3 and has a molar mass of 152.15 g / mol.
Uses / applications
Due to its structural characteristics, being a methyl ester derived from salicylic acid, methyl salicylate has a large number of uses in different areas.
One of the main uses (and the best known) of this substance is as a flavoring agent in different products: from the cosmetic industry as a fragrance to the food industry as a flavoring in sweets (chewing gum, candies, ice cream, among others).
It is also used in the cosmetic industry as a warming agent and for muscle massage in sports applications. In the latter case it acts as a rubefacient; that is, it causes superficial redness of the skin and mucous membranes when in contact with them.
In the same way, it is used in a cream for topical use, due to its analgesic and anti-inflammatory properties in treatments for rheumatic conditions.
Another of its applications includes its liquid use in aromatherapy sessions, due to its essential oil characteristics.
In addition to its use as a protection agent against ultraviolet radiation in sunscreens, its properties against light are being investigated for technological applications, such as the production of laser rays or the creation of species sensitive to storing information within molecules.
Synthesis of methyl salicylate
First of all, it should be mentioned that methyl salicylate can be obtained naturally from the distillation of the branches of certain plants, such as wintergreen ( Gaultheria procumbens ) or sweet birch ( Betula Slow ).
This substance was extracted and isolated for the first time in 1843 thanks to the scientist of French origin called Auguste Cahours; From wintergreen, it is currently obtained through synthesis in laboratories and even commercially.
The reaction that occurs to obtain this chemical compound is a process called esterification, in which an ester is obtained through the reaction between an alcohol and a carboxylic acid . In this case, it occurs between methanol and salicylic acid, as shown below:
CH 3 OH + C 7 H 6 O 3 → C 8 H 8 O 3 + H 2 O
It should be noted that the part of the salicylic acid molecule that is esterified with the hydroxyl group (OH) of the alcohol is the carboxyl group (COOH).
So, what happens between these two chemical species is a condensation reaction, because the water molecule present between the reactants is removed while the other reactant species are condensed in order to obtain methyl salicylate.
The following image shows the synthesis of methyl salicylate from salicylic acid, where two successive reactions are shown.