Why the carbon with two OH groups in organic compounds is unstable?

Discussion in 'Chemistry' started by adianadiadi, Apr 7, 2014.

  1. adianadiadi Registered Member

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    Why the carbon with two OH groups in organic compounds is unstable?
    For example, acetal hydrate is unstable due to two OH groups on one carbon and tends to lose water immediately.
     
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  3. rpenner Fully Wired Staff Member

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    I don't know what level of answer you want. The shortest, is "quantum chemistry of carbon-oxygen bonds." Slightly more useful is "it's unstable because there is a “nearby” lower energy alternative (carbonyl)."
    It is unstable, because the double bond in C=O is strong, which is part of the reason that burning hydrocarbons releases so much energy. But it's such a basic fact of nature that this is so, for it to be otherwise we would have to do chemistry in a different universe with different basic physical laws.
    http://www2.chemistry.msu.edu/faculty/reusch/virttxtjml/aldket1.htm

    See also: http://en.wikipedia.org/wiki/Geminal_diol
    For a 5% solution of formaldehyde in water, about 80% of it is in the the hydrated state.
    Other exceptions are:
     
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  5. wellwisher Banned Banned

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    Chloral hydrate below is an example of a stable situation of a carbon with two hydroxyl groups. This is used as a sedative. In this case, the three chlorine atoms are electron withdrawing, making it harder for one of the -OH groups to take elections and leave.


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  7. rpenner Fully Wired Staff Member

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  8. exchemist Valued Senior Member

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