Chemical Properties
colourless liquid with an odour of wintergreen
Definition
ChEBI: A benzoate ester that is the methyl ester of salicylic acid.
General Description
Colorless yellowish or reddish liquid with odor of wintergreen.
Reactivity Profile
METHYL SALICYLATE(119-36-8) is an ester. Esters react with acids to liberate heat along with alcohols and acids. Strong oxidizing acids may cause a vigorous reaction that is sufficiently exothermic to ignite the reaction products. Heat is also generated by the interaction of esters with caustic solutions. Flammable hydrogen is generated by mixing esters with alkali metals and hydrides. This chemical is incompatible with oxidizers. METHYL SALICYLATE(119-36-8) is also incompatible with strong bases. METHYL SALICYLATE(119-36-8) may react with iron salts.
Air & Water Reactions
Insoluble in water.
Hazard
Toxic by ingestion; use in foods restrictedby FDA, lethal dose 30 cc in adults, 10 cc in chil-dren.
Health Hazard
Harmful if swallowed, inhaled, absorbed through skin. Vapor mist is irritating to the eyes, mucous membranes, upper respiratory tract and skin. Ingestion of relatively small amount causes severe poisoning and death. Causes nausea, vomiting, acidosis, pulmonary edema, pneumonia, convulsions and death.
Fire Hazard
This chemical is combustible.
Occurrence
Numerous plants produce methyl salicylate in very small amounts. Some plants, such as the following, produce more:
Some species of the genus Gaultheria in the family Ericaceae, including Gaultheria procumbens, the wintergreen or eastern teaberry;
Some species of the genus Betula in the family Betulaceae, particularly those in the subgenus Betulenta such as B. lenta, the black birch;
All species of the genus Spiraea in the family Rosaceae, also called the meadowsweets.
This compound is produced most likely as an anti-herbivore defense. If the plant is infected with herbivorous insects, the release of methyl salicylate may function as an aid in the recruitment of beneficial insects to kill the herbivorous insects.Aside from its toxicity, methyl salicylate may also be used by plants as a pheromone to warn other plants of pathogens such as tobacco mosaic virus.
Preparation
Methyl salicylate can be produced by esterifying salicylic acid with methanol. Commercial methyl salicylate is now synthesized, but in the past, it was commonly distilled from the twigs of Betula lenta (sweet birch) and Gaultheria procumbens (eastern teaberry or winter green).
Production Methods
Methyl acetate, a novel acyl acceptor for biodiesel production has been developed, and a comparative study on Novozym 435-catalyzed transesterification of soybean oil for biodiesel production with different acyl acceptors has been studied (Noureddini et al., 2005).
Figure 1 shows the effect of the molar ratio of methanol to sunflower oil on the methyl ester yield for catalytic (3% CaO) transesterification in supercritical methanol at 523 K.
Composition
The leaves of wintergreen are reported to contain arbutin, caffeic acid, ericolin, ferulic acid, gaultherase, gaultheric
acid, gaultherin, gentisinc acid, methyl salicylate (5445 to 7920 ppm) o-pyrocatachuic acid, p-coumaric acid, p-hydroxybenzoic acid,
primverose, protocatachuic acid, syringic acid, tannic acid, tannin, tricontane and vallininc acid.
Aroma threshold values
Detection: 40 ppb
Taste threshold values
Taste characteristics at 10 ppm: sweet, salicylate and root beer with aromatic and balsamic nuances
Flammability and Explosibility
Nonflammable
Biochem/physiol Actions
Methyl salicylate plays an important role in fruit ripening. It is known to attract natural enemies of herbivores. MeSA inhibits the activity of aminocyclopropane-1-carboxylic acid synthase (ACC synthase) and aminocyclopropane-1-carboxylic acid oxidase (ACC oxidase) in plums and tomatoes, it can inhibit fungal infections and reduce chilling injury symptoms in fruits like pomegranates. This oil of wintergreen is of great interest in the tobacco industry as a flavorant. It has counter irritant and anti-inflammatory effects.
Safety
In pure form, methyl salicylate is toxic, especially when taken internally. A single teaspoon (5ml) of methyl salicylate contains 7g of salicylate, which is equivalent to more than twenty- three 300 mg aspirin tablets. The lowest published lethal dose is 101 mg / kg body weight in adult humans , (or 7.07 grams for a 70 - kg adult). It has proven fatal to small children in doses as small as 4 ml.[6] A seventeen-year- old cross - country runner at Notre Dame Academy on Staten Island, died in April 2007, after her body absorbed methyl salicylate through excessive use of topical muscle-pain relief products.
Most instances of human toxicity due to methyl salicylate are a result of over-application of topical analgesics, especially involving children. Some people have intentionally ingested large amounts of oil of wintergreen. Salicylate, the major metabolite of methyl salicylate, may be quantitated in blood, plasma or serum to confirm a diagnosis of poisoning in hospitalized patients or to assist in an autopsy.
Synthesis
By esterification from natural sources; by esterification of salicylic acid with methanol
Carcinogenicity
Available data suggest that
methyl salicylate is not carcinogenic.
Purification Methods
Dilute the ester with Et2O, wash with saturated NaHCO3 (it may effervesce due to the presence of free acid), brine, dry MgSO4, filter, evaporate and distil it. Its solubility is 1g/1.5L of H2O. The benzoyl derivative has m 92o (b 270-280o/120mm), and the 3,5-dinitrobenzoate has m 107.5o, and the 3,5-dinitrocarbamoyl derivative has m 180-181o. [Hallas J Chem Soc 5770 1965, Beilstein 10 IV 143.]
Toxicity evaluation
Oral LD50 values (mg/kg) for mouse, rat and rabbit are 1110, 887 and 1300, respectively. Oral LD50 values for child and adult human (mg/kg) are 228 and 506, respectively. Topical methyl salicylate generally rarely causes systemic toxicity, but it can be absorbed by the skin leading to stimulation of the central nervous system respiratory center, disturbance of lipid and carbohydrate metabolism, and disturbance of intracellular respiration. Severe poisoning can lead to acute lung injury, lethargy, coma, seizures, cerebral edema, and death. In the case of salicylate intoxication, treatment includes general supportive care, purification of the gastrointestinal tract with activated charcoal in the case of ingestion of salicylic acid, and monitoring of serum salicylic acid concentration. Bicarbonate infusion or hemodialysis can be used to enhance the elimination of salicylic acid.
