Where is the alcohol peak on 5-iodovanillin?

In summary, the speaker obtained 5-iodovanillin with a melting point of 182.7-183.5 C, slightly lower than the literature value of 183-185 C. However, the NMR spectrum does not show the expected alcohol peak, which is also barely visible on the SDBS spectrum. The speaker posted on a forum and was informed that this could be due to rapid exchange of the phenolic proton in acetone, which has a lower pka value than phenols. The issue has been resolved.
  • #1
mnmman
23
0
So I'm pretty sure I got 5-iodovanillin. The melting point in the literature is 183-185 C and I got 182.7-183.5 C. But my NMR spectrum isn't showing the alcohol peak. It barely shows up on the SDBS spectrum also (http://sdbs.db.aist.go.jp/sdbs/cgi-bin/direct_frame_top.cgi). Does anybody know why this is?
 

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  • #3
Well I posted on another forum and they said that it is probably to to rapid exchange of the phenolic proton on there. Makes sense because I used acetone and ketones have a lower pka value than phenols. So yes it is solved. Thanks tho
 

1. Where can I find information about the alcohol peak on 5-iodovanillin?

Information about the alcohol peak on 5-iodovanillin can be found in scientific literature, such as research articles and textbooks, as well as online databases and resources.

2. What is the chemical structure of 5-iodovanillin?

The chemical structure of 5-iodovanillin is C8H7IO3, with a molecular weight of 262.04 g/mol. It is a yellow crystalline solid with a melting point of 116-117 °C.

3. How is the alcohol peak on 5-iodovanillin identified?

The alcohol peak on 5-iodovanillin is typically identified through spectroscopy techniques, such as nuclear magnetic resonance (NMR) spectroscopy. The peak appears at a specific chemical shift and intensity, which can be compared to known standards for confirmation.

4. What factors can affect the location of the alcohol peak on 5-iodovanillin?

The location of the alcohol peak on 5-iodovanillin can be affected by various factors, such as the type of solvent used, pH level, and temperature. These factors can alter the chemical environment and interactions of the molecule, resulting in a shift in the peak location.

5. Is the alcohol peak on 5-iodovanillin always present?

The alcohol peak on 5-iodovanillin may not always be present, as it depends on the functional groups present in the molecule. If there are no alcohol groups (OH) present, then there will be no corresponding peak. However, other peaks related to the structure of 5-iodovanillin may still be present.

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