Question

1. The possible components of your mixture are unreacted ferrocene and the substituted ferrocene product(s) of your reaction, which should travel the farthest up the TLC plate (highest Rf) and why?

2. Which should have a higher Rf value: the mono-substituted ferrocene or the di-substituted ferrocene?

3. In the column chromatography portion of your experiment next week, you use different solvents or solvent mixtures to elute the column for separation of your product mixture. Why is this required? Why use solvent mixtures for column elution instead of pure solvents?

Answer 1

1)

The possible components of your mixture are unreacted ferrocene and the substituted ferrocene product(s)

as subtituted ferrocene is more polar than unsubstituted ferrocene so it will interact with the solvent in the TLC more so UNSUBSTITUED FERROCENE should travel the farthest up the TLC plate (highest Rf) and substitured will move little

2)As disubstitued ferrocene is less polar than mono substituted one because of the polarity of two group cancelout each others polarity so more polar one i.e mono substitued ferrocene will move less in the TLC plate and disubstituted ferrocene will move faster and hence having higher rf value

3) Because solvents are either polar or non polar they have no intermediate polarity so compounds having less polarity will came along with impurity if we add solvets separately

But we can controll our choice of polarity by using different polar and nonpolar solvent in different ratio of mixture so the separation of the compound will be neat and clean and finally we can get pure desired compound