Water is very polar and therefore absorbs very strongly on the polar stationary phase (alumina). Since benzil is less polar than benzoin, a polar solvent is used as solvent for the recrystallization. Benzil is less soluble in cold 95 % ethanol than benzoin causing the benzil to precipitate first.
In this manner, is fluorene polar or nonpolar?
It turns out that carbon and hydrogen don't have significantly different electronegativity values. Basically, that means that in our fluorene molecule the electrons (in the form of the covalent bonds) are being shared equally among all atoms. This makes fluorene a non-polar molecule.
Is Fluorenol polar?
A mixture of fluorene, fluorenone and fluorenol is examined by TLC and gives the following Rf values: 0.3, 0.5, 0.8. -0.8 is fluorene, 0.5 is fluorenone, 0.3 is fluorenol. -Fluorenol is an alcohol, so it is more polar than the ketone fluorenone, giving it a lower Rf value.
Why do we use column chromatography?
Column Chromatography is a preparative technique used to purify compounds depending on their polarity or hydrophobicity. In column chromatography, a mixture of molecules is separated based on their differentials partitioning between a mobile phase and a stationary phase.