Question

Consider the compounds 4-tert-butylcyclohexanol and 4-tert-butylcyclohexanone. using silica gel plates, which of the two compounds will have the higher rf value when ethyl acetate is the developing solvent? which will have the higher rf value when dichloromethane is the developing solvent? give your reasoning in each case.

Answer 1

1- we know that 4-tert-butylcyclohexanol is more polar than 4-tert-butylcyclohexanone (where the alcohols in general are more polar than ketons due to the hydrogen bond)
2- during separation via chromatography (in this case) the more polar solute will dissolve easily in polar solvents, where like dissolves like.
3- So, 4-tert-butylcyclohexanol will dissolve in ethyl acetete (which is polar) more than 4-tert-butylcyclohexanone, i.e, will have much higher Rf.
4- And also 4-tert-butylcyclohexanone will dissolve in dichloromethane (which lower in polarity than ethyl acetate) more than 4-tert-butylhexanol, i.e, will have much higher Rf