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Does the smell of alcohols increase as molar mass increases?

  1. Feb 20, 2015 #1
    Hello, I was just thinking about the pungent smell of alcohols and if they increase as the molar mass of the alcohol increases. For example, if I were to have samples of methanol, ethanol, propan-1-ol, butan-1-ol, and pentan-1-ol all at room temperature, would the alcohol's with the highest molar mass smell more "strongly" than the ones with lower molar masses. Or would it be the other way around?
     
  2. jcsd
  3. Feb 20, 2015 #2

    Quantum Defect

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    You would be having multiple things going on at the same time. As MW goes up, the vapor pressure goes down (due to increased intermolecular attraction). The "smell" will have to do with how the alcohol fits into the receptors in your nose. I believe that the current thinking is that these are activated by how well the molecule fits into the receptor. This "fit" might be different in the different receptors for the different alcohols. Certainly, you will have more non-specific interactions as the molecules increase in size.

    In my own experience, the different alcohols have very different smells. n-Butanol and n-Pentanol smell very "sweet" to me, while the shorter alcohols smell more solvent-ey (not sure what word describes the smell of methanol and ethanol.)
     
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