The Synthesis Of Aspirin ( Acetylsalicylic Acid )

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Abstract This report presents the synthesis of Aspirin (acetylsalicylic acid), as the product of the reaction of salicylic acid with ethanoic anhydride under acidic conditions. Aspirin was purified through recrystallisation by vacuum filtration, followed by desiccation of the Aspirin crystal over silica gel. The percentage yield was calculated as 44.89% and a sample of Aspirin was analysed using infra-red spectroscopy and compared to the spectrum of pure Aspirin, this served as an introduction to the identification of functional groups in organic compounds. The melting point was calculated using an IA9000M apparatus and recorded to be 35.2°C, which was slightly below the melting point of pure Aspirin; known to be between 138-140°C. Both IR spectroscopy and melting point measurement were used verify the purity of synthetic Aspirin made, which proved to be fairly pure under these laboratory conditions. Key Words Salicylic acid Aspirin Felix Hoffman Ethanoic anhydride Infra-red spectroscopy Acetic acid Health and Safety Laboratory coat and safety spectacles were worn at all times. Ethanoyl anhydride and concentrated sulfuric acid are highly corrosive. Ethanol is flammable, salicylic acid is irritant to eyes and skin. Chemicals were handled in the fume cupboard. Plastic gloves were worn throughout the experiment. Introduction Medicinal records of the properties and use of bark willow extend back to ancient civilisations such as the Chinese and Egyptians. By 400BC when
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