A 1.50 gram sample of 2-naphthol and naphthalene was diluted with 2.00 mL of methanol and loaded into a column packed with silica gel sludge in hexanes. Upon development, it was noted that all 1.50 gram sample came off in the first 3 fractions with no separations. Determine the technical mistake that was made and how to rectify the situation.
Methanol is a very polar solvent. It increased the polarity of eluting solvent system which washed out the mixture of compounds.
To rectify this, dry loading of the mixture is to be carried out. First, dissolve the 1.50 mixture of 2-naphthol and naphthalene in 2.00 mL methanol. Add 2.00 g silica gel to that and mix well. Evaporate the methanol to get a free flowing dry slurry. Load this dry slurry into the column packed with silica gel sludge in hexanes and put a cotton-plug on top. Naphthalene is a non-polar compound. It should elute in hexanes. Thus, first elute the mixture in hexanes and then gradually increase the polarity of the eluting solvent system to get good separation.
A 1.50 gram sample of 2-naphthol and naphthalene was diluted with 2.00 mL of methanol and...