1-Alkylimidazoles show many biological activities. In spite of very routine synthesis of these
compounds, their purification is not an easy process. Usually these agents used to be synthesized in benzen and purified by vaccum distillation. But due to the very high boiling point of these compounds an extremely high vaccum is required. In this study, there is an attempt to study the synthesis of these compounds in a less toxic solvent followed by their purification by column chromatography. Preparation of 1-alkylimidazoles was optimized as pharmaceutically active agents with high yield.Imidazole was refluxed with bromoalkanes in an alkaline medium and in the presence of quaternary ammonium salts as phase transfer catalysts (PTC), The crude products were extracted with organic solvents and then purified by column chromatography. Fourteen derivatives with alkyl chains including: ethyl, propyl, butyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, hexadecyl and octadecyl were synthesized. The chemical structure of the final products were confirmed by IR, NMR and mass spectrometric methods. The boiling point of alkylimidazoles increases as the length of alkyl chain increases. Therefore, a very high vaccum for distillation of the heavy analogues is needed which decreases the yield was used. Here column chromatography on silica gel was used for purification of 1- alkylimidazoles and also tolouene instead of benzene which is less toxic.