From: TILAK CHANDRA <0000058f112ac338-dmarc-request**At_Symbol_Here**LISTS.PRINCETON.EDU>
Subject: Re: [DCHAS-L] is drying chromatography media in open cans ok?
Date: Thu, 10 Oct 2019 14:04:11 +0000
Reply-To: ACS Division of Chemical Health and Safety <DCHAS-L**At_Symbol_Here**PRINCETON.EDU>
Message-ID: DM5PR0601MB37846D20F03A1B42E31CF75488940**At_Symbol_Here**DM5PR0601MB3784.namprd06.prod.outlook.com
In-Reply-To


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?

 

Hi, all,

 

I am searching for alternatives on behalf of a research group whose current practice is to invert columns with wet chromatography media over old shipping cans in fume hoods.  The issues are:

  • that the media is not readily transferable when it is wet
  • that the open can will be characterized as a violation by an environmental inspector since this is disposal by evaporation into exhaust.

Any alternatives you've encountered or experiences with environmental inspection verdicts on these would help immensely.

 

Thanks,

Melinda Box, M. Ed.
Organic Chemistry Lab Supervisor

Chem Dept Safety Officer

North Carolina State University

Department of Chemistry

Fox  328

Tel: (919) 515-2537

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