Column technologies

silica gel size: 5-20 mesh.
1. dry pack the column. use compressed air to tighten the silica gel.
2. add P.E. from the top. push it into silica gel by compressed air. leave some p.e. on the top.
3. mix the organic compound with a little organic solvent(the solvent should dissolve your compound but not carry it through the column. ex. toluene, dichloromethane) and add the mix to the top of the column.
4. push the mix into the column. then add sand to the column.
5. P.E. as the unpolar solvent, (hexanes is better, because it has a higher boiling point than p.e., so it is less likely to make a hot circle in your column), MTBE as the polar solvent.
6.if 40% MTBE in PE is not polar enough, DCM can be added into the solvent to improve the polarity. if more polar solvent is needed, acetone can be added.
7.better separation can be achieved by using different solvent combinations.
usually, polar solvents are: ethylacetate, MTBE, diethylether,acetone, acetonitrile
unpolar solvents: p.e., hexanes, DCM