I perform al alkylation reaction on an imdazole compound where the alkyl reagent (1-Iodo-Octane) was in excess. After the reaction was completed, I then performed an extraction, followed by removing the solvent (DCM) under the rota-vapour. As the proton NMR showed that the alkyl is still in excess, I then performed a column using a 1% ethyl acetate mixture with hexane. However, the alkyl remain in excess