Synthesis of Salicylic Acid from Wintergreen Oil Essay

1010 Words Nov 19th, 2012 5 Pages
EXPERIMENT 4: Synthesis of Salicylic Acid from Wintergreen Oil
Abstract: The purpose of this experiment is to take methyl salicylate (wintergreen oil) and by heating it under reflux with NaOH as a solvent, and then cooling the mixture with H2SO4 as another solvent, synthesize salicylic acid. The final step involves purify the product to produce as pure a sample of salicylic acid as possible. This process allowed for the successful production of 1.406g salicylic acid, an 82.70% yield. The NMR and IR both produced images that correlate with the known spectrums indicating a pure product. The melting point range was slightly wider, though did encompass the accepted melting point values.

Discussion: Reaction
OH O OCH3 2) H2SO4 1) 2NaOH OH
…show more content…
Determining limiting reagent:
1.595 ���� ������ℎ���� �������������������� ∗
15.0 ���� ������������ ℎ���������������� ∗

Amount of methyl salicylate used:
1 ����

Amount of sodium hydroxide:
2.13 g

1.174 ��

Theoretical yield:

Actual yield: 1.406 g Percent yield =

1.873 �� ������ℎ���� �������������������� ∗
1.406 �� ∗ 1.700 ��

Melting point range of purified product 150-162°C Mixed melting point range with salicylic acid: 153-160°C The melting point range of the synthetic salicylic acid includes the textbook value of 159°C. Although a greater variance was seen with the synthetic salicylic acid melting point range (range=12°C) versus the provided salicylic acid (range=7°C), the full range of the provided salicylic acid fell within the range of the synthetic salicylic acid, indicating a relatively pure product. It should be noted that optimally the melting point range should be slightly narrower. Loss of product occurred due to loss at each transfer step including, crystals stuck to the vacuum filter, crystals sticking to the glass stir rod for pH testing as well as the metal spatula used for recrystallization. While washing the crystals, some loss would also be seen due to the slight solubility of salicylic acid. I R:

10 0 = 8 2. 7 0%

(138.1 ��/������ ������������������ ��������) = 1.700 ��

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