Chemical Forums
Chemistry Forums for Students => Organic Chemistry Forum => Topic started by: HP on October 31, 2005, 11:54:25 AM
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Hi friends,
I am asking if someone know azeotropic mixture which have higher b.p than the both compounds itself? And if such exist what;s the explanation..
Thanks!
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Acetone and chloroform form an azeotrope that boils at 64.7 C, where acetone boils by itsself at 56.2 and chloroform boils at 61.2 C.
As far as an explanation, I think this occurs when the two components have a greater than expected attraction via intermolecular forces for one another, so it requires more energy to leave the liquid phase than it would normally take.
Can anyone back me up on this? Or better yet, tell us the correct answer? ;D
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For mixtures acetone/chloroform i found this abstract which try to explaintheir azeotropic mixture:
"Monte Carlo simulations in the grand canonical and isobaric-isothermal ensembles are used to investigate the phase behavior and structural properties of the binary mixtures acetone/chloroform, acetone/methanol and chloroform/methanol. These mixtures are of interest due to their complex phase behavior and hydrogen bonding interactions. Neat acetone and chloroform do not exhibit hydrogen bonding. When mixed, it is hypothesized that chloroform is able to form hydrogen-bonded complexes with acetone. The result is a minimum pressure azeotrope. Systems of acetone/methanol and methanol/chloroform should also exhibit significant hydrogen bonding interactions, however, neither displays a minimum pressure azeotrope."
Do someone know and could explain me what means "minimum pressure azeotrope" ?
Hope helpful for this discussion :)