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How will the addition of phenol to a solution affect the O2

  1. Jun 1, 2017 #1
    I asked a question regarding oxygen meters recently in another section of the forum but unfortunately no one seems to have used them before. So I thought I would break the problem down and ask a direct chemistry question...

    If I introduce phenol to a water solution will there be any reaction occurring that would effect the oxygen content? Further, if I degas the solution how would the presence of phenol effect the solutions ability to "hold" the oxygen in the solution?

    Thanks for any ideas, I can't seem to find any data on this on the internet.
  2. jcsd
  3. Jun 4, 2017 #2
    The phenol and water reaction involves decomposition of oxygen present in it,provided that the water is distilled and phenol to be conc.
    You can imagine the products of this reaction
  4. Jun 4, 2017 #3

    jim mcnamara

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    Staff: Mentor

    @John Dalton - I do not believe @rwooduk wants to imagine anything. Can you please be more specific? Imagine in this context means to create an answer based on little or no knowledge.
  5. Jun 5, 2017 #4


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    Gold Member

    I didn't know that phenol can be used as an oxygen meters. Could you give us the link to that thread so we can have some background on it?

    Here is my speculation on this. You might wanna take this with a grain of salt because I am not confident in the scale in which this reaction can occur.

    Oxygen gas are soluble in water (RT, 1 bar) for 40 mg/L (1.25 mmol/L). I think if the oxygen and phenol is to react, then concentration of phenol needs to be comparable (or larger) to the concentration of oxygen in order for it to lower the oxygen content. However, I think phenol and oxygen is inert, and we shouldn't be expecting a reaction without external stimuli. This is because oxygen is a triplet at ground state. Triplet state are usually inert with compounds of singlet ground state (most compounds are singlet at ground state and phenol is no exception) due to it being a spin-forbidden process. In order for a molecule to react to oxygen, they must be somehow converted to a triplet state. In this case, I suspect photo-oxidization to play a key role.

    I'm not very sure but I believe phenol have fast intersystem crossing to triplet state once excited by a photon. Phenol have nonbonding electrons on the oxygen atom, and one of the electrons can be excited to the π*-orbitals (n-π* transition). Phenol also have π-π* excited state. If triplet π-π* excited state is lower than singlet n-π* excited state, then intersystem crossing between these two states must be quite fast (due to large spin-orbit coupling between these two states), at least comparable to that of fluorescence. Then triplet excited state phenol can be produced and can react with oxygen as a spin-allowed process.

    I don't understand your second question. If you degas, there is no oxygen so the solution shouldn't be "holding" the oxygen at all.
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