Column Chromatography Lab Report

The purpose of this experiment was to determine the identity of isolated separated compounds using thin layer chromatography and column chromatography methods. In part A, four TLC were ran once each with ethyl acetate, hexane, toluene, DCM as solvent to separate a mixture. The stock solution is a mixture of benzophenone, biphenyl, and diphenyl methanol. The last trial include the comparison with the standard using the best solvent. It was predicted that toluene and hexane were the best solvent to elute a nonpolar mixture. Since the stationary phase is a silica gel that is polar, the solvent has to be nonpolar in order avoid the like to like interaction. Toluene and hexane were selected for being nonpolar, which is capable of moving

It was predicted that ferrocene will come off first because it had a lower molecular weight compare to acetyl ferrocene. In addition, ferrocene is less polar than acetyl ferrocene because it does not have oxygen in the structure. Not having oxygen reduce the ability for it to hydrogen bond. This mean that ferrocene would have less attraction to the gel compare to acetyl ferrocene. The prediction was correct because ferrocene, seen as a yellow layer, was first to separate. The second layer that was separated is acetyl ferrocene, which appeared orange. A TLC was ran to determine the Rf value of the yellow and orange layers. The yellow layer had an Rf value of .98, while the orange layer had a Rf value of .93. From these values, it was determined the higher Rf value was probably a more nonpolar solute since the gel is polar. Hence, ferrocene was the yellow layer and the acetyl ferrocene is the orange layer. Column chromatography can be separated from Part A through the same additions. The nonpolar compounds can be separated with addition of hexane. The polar compound such as diphenyl methanol would be added with ferrocene mixture. First, the benzophone would be separated in one flask. Second, biphenyl will be sepearted in another flask. Finally, diphenyl methanol is sepearated in another flask.