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I know that the ethyl acetate is polar and the hexane is nonpolar. I am trying to understand what if polar or nonpolar analgesics would travel further in TLC. I know that if ethyl acetate/hexane is polar than a more polar one will travel further, and if it is nonpolar then nonpolar will travel further.
There is only little correlation for a molecule to have dipole moment and being polar. The simplest and most prominent example is carbon dioxide, which is very polar, but has no dipole moment whatsoever. I am pretty certain, that the +/- charge separation is larger in benzene, than it is in hexane. Your ordering is therefore wrong. $\endgroup$
Further supporting this statement is the fact that methanol is less soluble in hexane, a nonpolar substance, than ethanol. Therefore ethanol is less polar. Plus, heptanol is hardly soluble in water, but according to the Princeton Review's logic, it should be even more soluble in water than methanol because it has a larger molecular mass.
Neat hexane (or a substitute such as petroleum ether or cyclohexane) is often used to wash 'grease' (non polar compounds) off the column, whilst neat ethyl acetate (or ether) is often used to elute highly polar compounds.
Hexane is nonpolar because it consists of carbon and hydrogen atoms linked by single covalent bonds. These bonds are symmetrical with similar electronegativities, resulting in an overall balanced ...
Solubility of alcohols in non-polar solvents. The solubility of an alcohol in a non-polar solvent (like hexane) increases with size of the alcohol, as the non-polar chain increases. However, as the chain keeps increasing, will the solubility eventually start to drop because the molecule becomes too large? Yes, I expect so. Think about the extreme.
I would argue differently from Mike. 9-fluorenone has one polar C=O C = O bond, but it also has two aromatic rings. Dispersion interactions are strong for such aromatic rings, and the point can be made that this factor will drive the solvation of 9-fluorenone in hexane. This is confirmed by the fact that 9-fluorenone is insoluble in water. 85.4k.
$\begingroup$ The reason non-polar molecules won't dissolve in polar solvents is believed to be due t0 enthalpy. When a non-polar molecule is added to a polar solvent (eg.water) stronger hydrogen bonds (or permanent dipole bonds) have to be broken to allow the non-polar molecule 'dissolve' (get surrounded by solvent molecules).
Miscibility of Hexane and Ethanol (Anhydrous vs 96%) In my lab, I mixed 8:2 (mass:mass) of Hexane:Ethanol. (Hexane: 0 ppm of water content, analytical grade, & ethanol: 4% water content, pharmacy grade) At room temperature, and at -20ºC, there was a clear phase separation. I repeated the experiment, but using anhydrous ethanol instead (1300 ...
If you increased the "polar" component of the mobile phase, it would travel further due to the mobile phase competing more for binding spots of the silica gel. So increasing the polarity of the mobile phase does raise $\mathrm{R_f}$ of aspirin (or anything) on regular silica gel.