One of the questions in my organic lab manual reads as follows: \"A student perf
ID: 1002246 • Letter: O
Question
One of the questions in my organic lab manual reads as follows: "A student performed the reaction in this experiment using a water bath at 90 instead of 50. The final product was tested for the presence of phenols with ferric chloride. This test was negative (no color observed); however, the melting point of the dry product was 122-125. Explain these results as completely as possible."
I tried researching the question online and couldn't really find an answer. Most websites only warned not to over heat the mixture but didn't explain why. I would very much appriciate anyone who could explain this to me! If there is a different mechanism as a result in the overheating, a drawling of this mechanism would also be much appriciated!
Explanation / Answer
Ferric chloride is not a recommended test for phenols because
a) not all phenols react.
b) it is a sensitive test, i.e. it depends on temperature,pH and concentration.
If the solution is too concentrated,or the temperature is too high the ferric oxidises the phenols, leading to the formation of free radicals and phenolic coupling.
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