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Topic: Comparisons of b.p. & m.p. between racemic mixture & its single enantiomer  (Read 7398 times)

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Offline Winga

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Comparisons of b.p. & m.p. between racemic mixture & its single enantiomer
« on: February 21, 2005, 10:43:59 AM »
From data, the melting point of racemic mixture is lower than that of its single enantiomer; while the boiling point of racemic mixture is lower than that of its single enantiomer.

How to explain these?
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Offline Donaldson Tan

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Re:Comparisons of b.p. & m.p. between racemic mixture & its single enantiomer
« Reply #1 on: February 21, 2005, 09:21:29 PM »
is this always true? i think it's because of the 3D projection of certain polar groups that bring about increased extent of intermolecular bonding
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Offline movies

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Re:Comparisons of b.p. & m.p. between racemic mixture & its single enantiomer
« Reply #2 on: February 22, 2005, 12:58:50 AM »
It's probably not always the case.

It depends on how molecules interact with their enantiomer.  Whenever you aggregate more than one chiral molecule you have a chance to make a diastereomeric complex (for example, the complex of two R enantiomers and the complex of one R and one S).  Diastereomers can have very different properties!
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