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Subject: Re: question
Date: Mon, 20 Jun 2011 14:05:41 -0400
Author: Kristi Ohr 		Next by Date:
Subject: Re: question
Date: Mon, 20 Jun 2011 19:02:26 -0500
Author: Todd Perkins


Date: Mon, 20 Jun 2011 14:05:21 -0400
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From: ILPI <info**At_Symbol_Here**ILPI.COM>
Subject: Re: question
In-Reply-To: <8C28F3F9C0708141A611C73B4D80E70E0D70DEF16F**At_Symbol_Here**VA3DIAXVS461.RED001.local>

This sounds more like a labeling (and, secondarily, training) issue than anything.  Base baths in my research labs all had NFPA and DOT Corrosive labels on them.  Adding the words FLAMMABLE and CORROSIVE might be a good idea as well.

The funny thing here is that base baths are always located next to a sink (and some folks store them IN the sink, but let's not go there....) which is an easier source of water than opening the lid....which begs the questions was there a lid at all, why was the lid off, or did he/she open the lid?   Again, a training and labeling issue.   Add KEEP COVERED AT ALL TIMES to the labeling suggestion.

While soap, water and scrubbing can get most glassware clean, nothing works quite as well and easily as a base bath for routine work, particularly in inorganic and organometallic labs where the residues can be very difficult to remove from inaccessible interior surfaces.  Base usually works better than acid (for example, Nochromix) because base actually eats the surface of the glass.  Glass rinsed off after exiting a base bath usually runs off in a clean film with no beading.  And, for the most part, base baths last a long time without any need for disposing of them as waste as long as the users clean most of the major crud off the glassware before soaking - at most they usually need an occasional "topping up".

I have heard of folks using aqueous KOH plus potassium phosphate which avoids the flammability issue, but have never tried it myself and can't vouch for its effectiveness.  Another way of reducing the flammability risk is to go to a higher-boiling alcohol or polyol, but then you run into health and environmental issues, most likely.

Flame drying glassware is still done on rare occasions for the most highly-sensitive water-sensitive materials, mostly for small-scale reactions performed on high vacuum systems.  I can't comment on the appropriateness of the method in this case with the information at hand, of course.

Rob Toreki

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On Jun 20, 2011, at 12:24 PM, Demer, Frank R - (demer) wrote:

One of our labs had a base bath fire over the weekend.  A researcher forgot there was alcohol in the bath and tried to extinguish a match, used to light a propane torch, in the bath.  Besides the obvious problem of using matches instead of a striker and the questionable use of a propane torch to dry glassware for a moisture sensitive reaction, can anyone recommend an alternative to a base bath containing KOH solution, iso-propanol and ethanol?  
Frank R. Demer, MS, CIH, CSP
Health Safety Officer
Industrial Hygiene and Safety
University of Arizona
Department of Risk Management Services
Phone:  520.621.3585
Fax:  520.621.3706
Mailing Address:  P.O. Box 210300, Tucson, AZ  85721-0300
Street Address:  220 W. 6th St., Tucson, AZ 85701 (2nd floor, East Bldg.)
Web Address:  risk.arizona.edu

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