From:
Craig Merlic <merlic**At_Symbol_Here**CHEM.UCLA.EDU>
Subject:
Re: [DCHAS-L] [NAOSMM] Rotovap Vacuums and Condensers
Date:
Jan 9, 2024 19:07 UTC
Reply-To:
ACS Division of Chemical Health and Safety <DCHAS-L**At_Symbol_Here**Princeton.EDU>
In-Reply-To:
Re: [DCHAS-L] [NAOSMM] Rotovap Vacuums and Condensers
All,
Anyone using a rotovap should be using a condenser with dry ice or a recirculating chiller set to a low temperature.
Tap water is generally not cold enough for efficient condensation of low boiling solvents. Hence, if one uses a water aspirator the organic solvents end up going into the lab air and also down the drain. If one uses a mechanical pump they often produce lower pressures, so even more solvent can be blown out in to the lab air. Sometimes with mechanical pumps set to low pressures one even needs to use two dry ice condensers in series.
Craig A. Merlic
Professor of Chemistry, UCLA Department of Chemistry and Biochemistry
Executive Director, UC Center for Laboratory Safety
From: ACS Division of Chemical Health and Safety <DCHAS-L**At_Symbol_Here**Princeton.EDU> on behalf of James Kaufman <jkaufman**At_Symbol_Here**LABSAFETYINSTITUTE.ORG>
Reply-To: ACS Division of Chemical Health and Safety <DCHAS-L**At_Symbol_Here**Princeton.EDU>
Date: Tuesday, January 9, 2024 at 8:18 AM
To: <DCHAS-L**At_Symbol_Here**Princeton.EDU>
Subject: Re: [DCHAS-L] [NAOSMM] Rotovap Vacuums and Condensers
I recall when the town of Newburyport, MA put in water discharge restrictions that caused Strem Chemical Co to stop using a water aspirator and purchase a separate vacuum pump. They added a cold trap to the line.
Why don't you do an experiment and put a cold trap between your Rotovap and the house vacuum? ... Jim
PS. LSI now has virtual lab inspections, safety program evaluations, document reviews, plus courses and seminars ... all virtual. And, a complimentary, updated version of our classic Laboratory Safety Guidelines is now available on our website ... https://www.labsafety.org/product/lab-safety-rules
James A. Kaufman, PhD
Founder/President Emeritus
The Laboratory Safety Institute (LSI)
A Non-profit Educational Organization
for Safety in Science, Industry, and Education
192 Worcester Street, Natick, MA 01760-2252
(O) 508-647-1900 (F) 508-647-0062 (C) 508-574-6264
Skype: labsafe; 508-401-7406 jkaufman**At_Symbol_Here**labsafety.org www.labsafety.org
Teach, Learn, and Practice Science Safely
Hello, fellow NAOSMMites!
Our school has recently begun questioning the equipment and procedures we use when rotovap-ing in our organic labs. Currently, we evaporate off using the house vacuum and condense using a cold-water coil condenser that is just connected to the domestic cold-water supply. I would just like some feedback and input as to what some of you are using and why.
For context, our science building is about 20 years old, and for many years has had a history of causing many latex/rubber/elastic objects to deteriorate in a short amount of time and in weird ways (anyone else have melting cabinet bumpers?) Administration and facilities have done a few things to try to get to the bottom of what could be causing this, and the most recent thing they've hit on is that it could possibly be vapors from the rotovap leaking into the air somewhere that is contributing to this. Our one-and-only organic professor admitted that only a fraction of the solvents that are boiled off are actually condensed and recaptured by the current condensing setup, so administration asked facilities to verify that the house vacuum vents outside (and not just into the pump room) which they were able to do. Even with that information, they are pursuing the idea of purchasing a stand-alone vacuum to put in a hood to pull the vacuum for the rotovap. In my mind, this would be a less optimal solution than using the house vac, at least from the standpoint of trying to release as few solvents into the building air as possible.
We are also looking at solutions to increase condensation rates such as an electric water chiller, which I think does make sense, but I'm also interested in hearing what you use for that.
Thanks in advance for any input!
-----
Jeremy Vanderhyde
Science Laboratory Services &
Building Manager, Generac Hall
Wisconsin Lutheran College
8800 W. Bluemound Rd.
Milwaukee, WI 53226
Work: 414-443-8766
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