preview

Aspirin Synthesis Lab Report

Decent Essays

Olivia Isaacs
C127
11 November 2014
The Synthesis and Characterization of Aspirin
Objective:
In this experiment, aspirin was synthesized from acetic anhydride and salicylic acid made in order to characterize its properties and determine its purity. The purity of the aspirin was examined by its melting point, thin layer chromatography, and UV spectroscopy.
Introduction:
Aspirin is synthesized by the formation of acetic anhydride and salicylic acid with the presence of a catalyst (Salicylic Acid + Acetic Anhydride → Acetyl Salicylic Acid + Acetic Acid1). During the synthesis, the catalyst donates an H+ that attaches on to the reaction, but is not consumed.2 Once the salicylic acid has completely dissolved the reaction is complete. Salicylic …show more content…

The purity of the aspirin is analyzed by its melting point, thin layer chromatography, and UV spectroscopy. The melting point of a solid is when the molecules have enough thermal energy to overpower their intermolecular forces, breaking the bonds apart.5 This results in the solid turning into a liquid. When observing the melting point, a low melting point indicates more impurities, whereas a high melting point indicates very few impurities in the substance.2 If the substances being tested consist of impurities, the intermolecular forces are weakened causing a lower melting point to be reached. When experimenting …show more content…

The temperature was recorded when melting started and when it finished. When finished, the capillary tubes were removed and the apparatus was shut off.
Thin Layer Chromatography:
A glass jar was obtained and filled with 0.5 cm of the solvent consisting of hexane, ethanol, and ethylacetate. The lid was put on so it could become saturated with vapor.
A TLC plate was obtained and a line was drawn in pencil 1 cm from the bottom. The line was divided into four hash marks (A, SA, P, C).
Add 0.2 g of the aspirin, salicylic acid, pure salicylic acid, and crude were put into labeled test tubes. 1 mL of methanol was added to the test tubes and was then stirred until the crystals dissolved.
The solutions were drawn up using capillary tubes and dotted on the four hash marks on the TLC paper. Each of the dots were spotted twice rather small.
The TLC paper was then put into the glass jar containing the solvent. The lid was put on until the solvent traveled within 2 cm of the top of the plate. It was then removed and the solvent was immediately marked before it dried.
Once the plate dried, it was put under a UV lamp. The spots were marked with a pencil.
UV Spectroscopy:
5 mL of salicylic acid and 8 mL of the iron solution was obtained in a test

Get Access