Question

These questions are from an experiment where we had a mixture of Ferrocene, acetylferrocene and diacetyl ferrocene and we separated each by using column chromatography. Before doing the column chromatography we did TLC analysis to ensure that we did, in fact, have a mixture of these 3 compounds.

During the column chromatography we first eluted the ferrocene using pure hexane. Then we eluted the acetylferrocene using a 1:1 mixture of hexane and methylene chloride. Then we eluted the diacetylferrocene using a 9:1 mixture of hexane and methylene chloride.

1. Rank ferrocene, acetylferrocene, and diacetylferrocene in order of increasing polarity. Do the TLC results from your fractions support this ranking? Explain.

Answer 1

Ferrocene, Acetylferrocene, and Diacetylferrocene can be ranked by increasing polarity based on their elution order from column chromatography and corresponding R₏ values in TLC analysis, with Ferrocene being the least polar, followed by Acetylferrocene, and Diacetylferrocene as the most polar.

Step-by-step explanation:

The substances Ferrocene, Acetylferrocene, and Diacetylferrocene can be ranked in order of increasing polarity based on their behavior during column chromatography and TLC analysis. Ferrocene, having no polar functional groups, is the least polar and was eluted first using pure hexane, a nonpolar solvent. Acetylferrocene, with one acetyl group, has a higher polarity and required a 1:1 mixture of hexane and methylene chloride for elution. Diacetylferrocene, with two acetyl groups, is the most polar and required a stronger polar solvent mixture (9:1 mixture of hexane and methylene chloride) to elute. The TLC results should support this ranking, as Ferrocene would have the lowest Rf value (indicating the least interaction with the polar stationary phase), followed by Acetylferrocene with a higher Rf value, and Diacetylferrocene with the highest Rf value, assuming a typically polar stationary phase for TLC.