Methyl Salicylate

Synonyms: gaultheria oil, wintergreen oil
cas number: 119-36-8, molecular weight: 152.15, chemical formula: c8h8o3, einecs ec number: 204-317-7, fema: ----,
methyl salicylate bp grade
ph eur
c8h8o3 -- 152.1 -- 119-36-860-7
action and use: counter-irritant.
Definition
methyl 2-hydroxybenzoate.
Content: 99.0 per cent mm to 100.5 per cent mm.
Characters
appearance: colourless or slightly yellow liquid.
Solubility: very slightly soluble in water, miscible with ethanol (96 per cent) and with fatty and essential oils.
Identification
a. Heat 0.25 ml with 2 ml of dilute sodium hydroxide solution on a water-bath for 5 min. Add 3 ml of dilute sulphuric acid. A crystalline precipitate is formed. Filter. The precipitate washed with water and dried at 100c-105c, melts at 156c to 161c.
B. To 10 ml of a saturated solution add 0.05 ml of ferric chloride solution. A violet colour develops.
Tests
appearance of solution: the solution is clear and not more intensely coloured than reference solution.
To 2 ml add 10 ml of ethanol (96 per cent).
Acidity: dissolve 5.0 g in a mixture of 0.2 ml of bromocresol green solution and 50 ml of ethanol (96 per cent) previously neutralised to a blue colour by addition of 0.1 m sodium hydroxide. Not more than 0.4 ml of 0.1 m sodium hydroxide is required to restore the blue colour.
Relative density: 1.180 to 1.186.
Refractive index: 1.535 to 1.538.
Assay
dissolve 0.500 g in 25 ml of ethanol (96 per cent). Add 0.05 ml of phenol red solution and neutralise with 0.1 m sodium hydroxide. To the neutralised solution add 50.0 ml of 0.1 m sodium hydroxide and heat under a reflux condenser on a water-bath for 30 min. Cool and titrate with 0.1 m hydrochloric acid . Calculate the volume of 0.1 m sodium hydroxide used in the saponification. Carry out a blank titration.
1 ml of 0.1 m sodium hydroxide is equivalent to 15.21 mg of c8h8o3.