Methyl salicylate is an organic compound with the formula C₈H₈O₃. It is the methyl ester of salicylic acid. It is a colorless, viscous liquid with a sweet, fruity odor reminiscent of root beer, but often associatively called "minty", as it is an ingredient in topical analgesics, liniments, and flavor and fragrance formulations. Molecular weight is 152.15 g mol, CAS 119-36-8, boiling point 220 to 222 C at atmospheric pressure, density about 1.176 g mL at 20 C, refractive index nD20 1.537 to 1.539, and flash point approximately 90 C closed cup. It is sparingly soluble in water and miscible with common organic solvents. Typical manufacture routes use esterification of salicylic acid with methanol under acid catalysis; the material is commercially supplied as a technical grade or high purity grade and is commonly assayed by gas chromatography with flame ionization detection and confirmed by NMR or IR. Common specifications include assay by GC greater than or equal to 99.0 percent for high purity grades, acid value less than 0.5 mg KOH g, and water content below 0.2 percent by Karl Fischer. For handling, use appropriate ventilation, avoid contact with eyes and mucous membranes, and store in a cool, well ventilated area away from strong oxidizers.
Parent: Methyl Salicylate
Parent: Methyl Salicylate
Parent: Methyl Salicylate
Parent: Methyl Salicylate
Parent: Methyl Salicylate
Commercial and laboratory grades of methyl salicylate can contain trace amounts of unreacted starting materials and process related compounds; typical impurity and related compound limits for a high purity grade are: salicylic acid less than 0.05 percent w w, residual methanol less than 0.10 percent w w, water content less than 0.20 percent w w, total related esters and isomeric hydroxybenzoate esters (for example ethyl salicylate, methyl 4 hydroxybenzoate) typically less than 0.20 percent w w combined, salicylaldehyde and other minor oxidation products less than 0.05 percent w w, and nonvolatile residue or ash below 0.02 percent w w. Heavy metals are generally controlled to low ppm levels typically under 5 ppm for lead and cadmium and chloride and sulfate impurities under 10 ppm where required. Typical analytical controls use GC FID for organic volatile impurities, HPLC for polar impurities such as salicylic acid, Karl Fischer for water and ICP MS or AAS for metals.
Methyl salicylate is used as a topical counterirritant and analgesic in rubs and liniments, as a fragrance and flavoring agent at controlled levels in food and personal care applications, as a solvent or intermediate in chemical synthesis, and in some formulations as a fragrance note in perfumery.
At recommended concentrations and for short term use, methyl salicylate is used safely on intact skin in many over the counter products, but it can cause local irritation or sensitization in some individuals and can produce systemic salicylate absorption if applied to large areas, under occlusion, or to damaged skin. Follow product label directions, avoid use on broken skin, and consult healthcare guidance before applying to children or using with other salicylate containing medications.
Methyl salicylate can be toxic if ingested, inhaled in large quantities, or absorbed systemically in sufficient amounts; concentrated oil of wintergreen based on methyl salicylate can deliver potentially lethal doses if swallowed, especially in children. Toxicity manifests as salicylate poisoning with symptoms like nausea, vomiting, tinnitus, hyperventilation, and metabolic disturbances, so accidental ingestion or excessive topical exposure requires prompt medical attention.
Hazards include skin and eye irritation, potential for allergic contact dermatitis in sensitive individuals, systemic toxicity from significant absorption or ingestion, and it is combustible so standard flammable liquid precautions apply. Use personal protective equipment for handling, ensure good ventilation, store away from heat sources and strong oxidizers, and follow local regulatory and safety data sheet guidance for spill response and disposal.
