EXPERIMENT #1: SYNTHESIS OF ASPIRIN
Ryan and Jose
The purpose of this experiment is to synthesize aspirin (acetyl salicylic acid) from salicylic acid and acetic anhydride. The purity of the product is tested using the melting point, Thin Layer Chromatography, and High-performance liquid chromatography. The resulting percent yield is 30.14%.
Tare weight of Buchner funnel: 5.60 g
Buchner funnel + dried aspirin: 5.993 g
Yield of Aspirin: 0.393 g
- Crude: 95.5 C to 96.0 C
- Recrystallized: 125.5 C to 130.5 C
- Commercial: 132.5 C to 136.4 C
From left to right (commercial, recrystallized, crude)
- Commercial: 0.917
- Recrystallized: 0.875
- Crude: 0.959
Stationary: (SO2, Silica)
Mobile: (50:50, Acetone, water)
HPLC printout is attached
-Yield of aspirin
Weight of the Buchner funnel including the dried aspirin, minus the weight of the Buchner funnel alone.
5.993 – 5.60 = 0.393
Rf = distance analyte travelled/distance front line travelled
Commercial: 4.4/4.8 = 0.917
Recrystallized: 4.2/4.8 = 0.875
Crude: 4.6/4.8 = 0.959
Salicylic Acid = 1.0 g. Molecular weight of Salicylic Acid = 138.12 g/mol
1.0/138.12 = 0.00724 mol Salicylic Acid
Acetic Anhydride = 2.0 mL. Density = 1.08 g/mol. Molecular weight = 102.9 g/mol
(2.0)(1.08) = 2.16. 2.16/102.9 = 0.0210 mol Acetic Anhydride
Salicylic Acid is the limiting reagent.
-Moles of aspirin
0.393g/180.15g/mol = 0.00218 mol
-Theoretical Yield and & Yield
.00724/.00218 = 0.301 mol (100%) = 30.1%
The procedure for the synthesis of aspirin was relatively simple, although consisted of many steps. The greatest source of error during the procedure arises from the fact that the reactants and products are transferred between containers multiple times. Another source of error is ensuring that the reactants have reacted as...