Dry silica gel is always easy to remove from the column as compared to wet silica gel.  Maximum glass columns break/crack during the silica gel removal process, also, the glass columns are expensive.

 

For normal column, where 60-120 mesh size silica gel is used, generally the gravity method will work to remove eluent solvent; however, 200-400 mesh silica gel column (flash chromatography) slight nitrogen pressure is needed to remove the excess solvent from the surface of silica gel. Never use uncontrolled pressure for eluting the column. Use a proper regulator to control the pressure inside the column.

 

Therefore, it is prudent practice to dry the column before transferring the used silica gel into a waste container to avoid extra work and solvent exposures.

References:

1.       Still, W. C.; Kahn, M.; Mitra, A. J. Org. Chem. 1978, 43, 2923.

2.       Ponten, F.; Ellervik, U.  J. Chem. Educ. 2001, 78, 363.

3.       Bell, W. L.; Edmondson, R. D. J. Chem. Educ. 1986, 63, 361.

4.       Thompson, W. J.; Hanson, B. A. J. Chem. Educ. 1984, 61, 645.

5.       Friedel, M. G., Berteau, O, Pieck J. C., Atta M, Ollagnier-de-Choudens S, Fontecave M, Carell T. Chem. Commun., 2006, 445.

Tilak

From: ACS Division of Chemical Health and Safety <DCHAS-L**At_Symbol_Here**PRINCETON.EDU> On Behalf Of Melinda Box
Sent: Wednesday, October 09, 2019 3:36 PM
To: DCHAS-L**At_Symbol_Here**PRINCETON.EDU
Subject: [DCHAS-L] is drying chromatography media in open cans ok?

 

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