Salicylic Acid Lab Report

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2-hydroxybenzoic acid, C6H4(OH)COOH - commercially known as salicylic acid exists as a colourless, crystalline organic carboxylic acid. It is partially soluble in water and completely soluble in ethanol and ether. This acid is very commonly used in the preparation of its ester derivatives as it contains both a hydroxyl (-OH) and a carboxylic (-COOH) group. Due to the presence of these functional groups, it is able to react with both an acid and an alcohol.1 (“Salicylic acid”). The very first preparation of salicylic acid was made by Italian chemist Raffaele Piria in 1838 from salicylaldehyde.2 (Brown). The bark and leaves of the willow tree are natural sources of salicylic acid having both analgesic and antipyretic properties. However it is…show more content…
This was first done by Italian chemist, Piria (1839). Salicin hydrolyses in aqueous media to form glucose and salicylic alcohol (saligenin). Salicylic alcohol is then oxidised to form salicylic acid. (Schrör 2010)

Another natural source of salicylic acid is methyl salicylate present in wintergreen oil. Salicylic acid is obtained by hydrolysing methyl salicylate, an ester under basic conditions. This synthesis takes place through a 2-step organic reaction. It is also referred to as saponification. Saponification is a special type of hydrolysis which converts an ester into an alcohol and a carboxylic acid.

The first step (1) of the hydrolysis, involves the addition of NaOH to methyl salicylate. The reaction is then put under reflux. This produces the sodium salt of salicylic acid known as sodium salicylate. The end products of saponification are alcohol and carboxylic acid. Therefore, in the second step (2), the sodium salicylate collected is then acidified using sulphuric acid to convert the organic salt into the protonated carboxylic acid, salicylic acid. Since the acid is a solid, it be easily isolated from the alcohol produced, methanol, and then purified by crystallisation. The mechanism of

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