Chemical Forums
Chemistry Forums for Students => High School Chemistry Forum => Topic started by: nela.maze on November 24, 2021, 12:00:56 PM
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Dear Chemists,
Last week we had alkenes in school. We briefly covered the theme of the reaction of ethene with potassium manganate(VII) in a neutral environment. We did the redox reactions to this, and it was something like this:
2 MnO4- + 3 CH2=CH2 + 4 H2O :rarrow: 2 MnO2 :spindown: + 3 CH2OH-CH2OH + 2 OH-
However, we did not talk about what happens in an acidic or alkaline environment. I googled it but couldn't find it anywhere. So I just assumed the product was still ethylene glycol. Why? Because when manganate reacts with another reducing agent, for example, SO32-, this reagent in all environments ends up being SO42-. That is why I assumed that in all environments ethene turns to ethylene glycol. Is that true?
I also did the redox reactions and they seem okay
in an acidic environment:
2 MnO4- + 5 CH2=CH2 + 6 H+ + 2H2O :rarrow: 2 Mn2+ + 5 CH2OH-CH2OH
in an alkaline environment:
2 MnO4- + CH2=CH2 + 2 OH- :rarrow: 2 MnO42- + CH2OH-CH2OH
Please tell me if it's right and if it's not right, what do we get when ethene reacts with potassium manganate(VII) in and acidic and alkaline environment.
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The lower the pH, the stronger oxidizing properties of permanganate, and alcohols are quite easy to oxidize further.