Date: Thu, 11 Sep 2008 09:27:13 -0400
Reply-To: ILPI <info**At_Symbol_Here**ILPI.COM>
Sender: DCHAS-L Discussion List <DCHAS-L**At_Symbol_Here**LIST.UVM.EDU>
From: ILPI <info**At_Symbol_Here**ILPI.COM>
Subject: Re: Pressure tube for organic synthesis
Comments: cc: Tan Khai Seng
In-Reply-To: <B25C370F3F6ADF4D94FE33CE1698D1B1035C6603**At_Symbol_Here**MBX03.stf.nus.edu.sg>

>Has anyone encountered accidents involving glass pressure tubes which
>were commonly used for organic synthesis in research labs? One example
>of this can be found from Ace glassware
>http://www.aceglass.com/html/2008/html/index_html.php?page=714
>

The second incident occurred in my laboratory while I was away at a 
Gordon conference.  As you can see, the lessons learned from the 
previous accident were learned!

The student was heating a small glass bomb with DMSO as the solvent. 
DMSO can be heated to 150 C with little decomp when pure, but 
self-accelerating decomposition acid or base reactions can occur at 
lower temperatures; a hazard of which we were aware.

What made the difference here is that we prepared for a possible 
pressure explosion, as you should when you heat any solvent in a 
closed vessel anywhere near its boiling or flash point or when there 
is the possibility of thermal decomposition.

When the bomb exploded (in the middle of the night), it was in a fume 
hood.  The only objects in the fume hood were the bomb, the heating 
apparatus, and a blast shield.  The fume hood sash was closed.   No 
injuries, no 911 calls, and the only damage was a shattered ceramic 
stirplate.

To recap, all glass bomb reactors should be used in a fume hood, 
behind a blast shield, and with nothing else in the fume hood. 
Students should not try to touch the apparatus until it has cooled, 
and always keep the shield/sash between themselves and the materials.

Best regards,

Rob Toreki
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