Date: Wed, 7 Dec 2011 16:35:34 +0000
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From: 8524828hau**At_Symbol_Here**COMCAST.NET
Subject: Re: Isovaleryl chloride odor control
In-Reply-To: <3845C2D8-7A3D-4D3A-A878-EC12068C67EF**At_Symbol_Here**>

I agree that reaction with water vapor would result in the conversion of the reagentto the corresponding carboxylic acid, with subsequent slow off-gassing from tissues/gloves/syringe/septa, needles etc.  A practical solution is to keep all such materials in the hood for a few weeks in shallow pan, assuring that all surfaces are exposed to moving air.  An obvious chemical"neutralization" is conversion of the trace of carboxylic acid to the corresponding ester by addition of an alcohol under some appropriate condition I will not venture to suggest. 

David Haugen
Argonne National Laboratory - retired

From: "ILPI" <info**At_Symbol_Here**ILPI.COM>
Sent: Wednesday, December 7, 2011 8:15:26 AM
Subject: Re: [DCHAS-L] Isovaleryl chloride odor control

That will hydrolyze to the corresponding carboxylic acid, isovaleric acid = 3-methylbutyric acid.  

 I have no experience with the material, but I imagine that it is similar to  butyric acid in its odor characteristics and staying power.   Butyric acid has such a low odor threshold and strong odor response that one could screw the cap off the bottle in a large room, cap it again, and the room would reek for some time.  I had a friend who handled the stuff with gloves and a syringe.  He claims it didn't spill, butwhen he was done his hand reeked of butyric acid.  It took numerous hand washings with various attempted neutralization agents over several hours for him to get it off.  After each try his hands would smell clean, but after a minute or so the stuff would work its way out of his skin and start reeking again.

I suspect that what happened is that a tiny amount of this material dripped or absorbed somewhere outside- on the bench, the floor, a lab coat, the sharps disposal box, on the used gloves in the trashcan, etc. in which case it could linger for days and days.  The solution would be to chemically neutralize it or throw away the contaminated waste/equipment.

Rob Toreki

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On Dec 7, 2011, at 8:13 AM, Ralph B Stuart wrote:

I'm investigating a situation in which someone was working with isovaleryl chloride which led to an odor release that lasted for a week. After the material was extracted from the stock container with a syringe in a hood, it was used in a Schlenk line outside the hood. Preliminary examination of the hood with dry ice indicates that it's maintaining containment. Thelab's general ventilation rate is high, as there are 10 feet of hood spacein 700 square feet of floor space.

I wonder if anyone has experience with a similar situation that could help explain there the odor came fromand why lasted so long?

Thanks for any information about this.

- Ralph

Ralph Stuart CIH
Laboratory Ventilation Specialist
Department of Environmental Health and Safety Cornell University


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