Date: Tue, 6 Jul 2010 15:20:18 -0400
Reply-To: DCHAS-L Discussion List <DCHAS-L**At_Symbol_Here**LIST.UVM.EDU>
Sender: DCHAS-L Discussion List <DCHAS-L**At_Symbol_Here**LIST.UVM.EDU>
From: Kim Auletta <kauletta**At_Symbol_Here**NOTES.CC.SUNYSB.EDU>
Subject: Re: Sol-gel drying process
In-Reply-To: <F5D83326DC77FD4EA138E9194D6B2888337233F7EE**At_Symbol_Here**>
Its important to know if the oven is rated for flammable solvent/vapors. 
In another life I inspected a facility that used methanol as a binder in 
an oven that was not rated for flammables. The large door ended up across 
the room & the yellow powder was everywhere. 

Kim Auletta
Lab Safety Specialist
EH&S    Z=6200
Stony Brook University
EH&S Web site:

Remember to wash your hands!

"Tsiakals, Nicholas John" 
07/06/2010 03:16 PM
Re: [DCHAS-L] Sol-gel drying process
Sent by:
DCHAS-L Discussion List 

Can’t say I’m familiar with the chemistry.  Even so, I would turn these 
questions back at the lab(s) involved:
What were the intermediates/byproducts produced?
What was being evaporated at the hood?  At the oven?  
I question the hot plate boil-off and the convection oven for solvent.  
(If flammable atmospheres, then intrinsically safe electrical components 
(Did the convection oven vent to the room?)
Solvent/vapor recovery would be more robust – required at larger scale.
Does the person involved appreciate:  
Consequences were limited in this case by unwitting accidents of scale and 
I realize this is unrefined, but this is where I would start with the 
From: DCHAS-L Discussion List [mailto:DCHAS-L**At_Symbol_Here**LIST.UVM.EDU] On Behalf Of 
Perry Cooper
Sent: Tuesday, July 06, 2010 11:04 AM
To: DCHAS-L**At_Symbol_Here**LIST.UVM.EDU
Subject: [DCHAS-L] Sol-gel drying process
Sharing an incident. Anyone want to chip in on recommendations? J
General lab exhaust through the fume hood. Some equipment exhausted with 
localized flex duct but not the oven.
Adjacent areas complained of strong alcohol odor.
"….. intent to prepare a batch of fine particulate size aluminum oxide via 
the sol gel process. The components were an organometallic (aluminum sec- 
butoxide), a solvent (2-propanol) and water.  1.5l of 2-propanol was 
placed in a porcelain-lined steel container. 4.5kg of aluminum 
sec-butoxide was added to the solvent while mixing. After these components 
were thoroughly mixed, 1.1l of water was added resulting in the formation 
of AlOH particles from the organic precursor.  At this point, the 
composition was a viscous slurry. In order to reduce the solvent content, 
the container was placed on a hot plate inside the fume hood. The 
composition was heated (temperature unknown but estimated to be 70-80°C) 
for approximately 4 hours.  At the end of this period, most of the solvent 
had evaporated, leaving a slightly moist "cake". In order to remove the 
remaining solvent, the container was taken to room xxxxx and placed in a 
convection oven. I partially covered the container with a lid to allow 
venting and to prevent any swirling debris from contaminating the 
material. Oven temperature was set at 130°C and the general exhaust in 
this room was turned on. My intent was to let the material dry overnight 
and I left for the day. When I returned the following day, I checked the 
oven and it was apparent that there had been an accident at some point 
after I left.  I later learned that there had been a small explosion and 
fire. I believe the fire was confined to the oven and was extinguished by 
covering the container with the lid.  The oven door was bent when it swung 
open and contacted the control enclosure but no other damage is apparent. 
In the past, I have used these same procedures and equipment to make 
similar compositions without incident…."
Perry D. Cooper, MS, HEM, CCHO
Manager - HSE - JHU

The Johns Hopkins University
Health, Safety & Environment

Homewood Campus Safety Office
3400 N. Charles Street
G04 Wyman Park Bldg
Baltimore, MD 21218
Office: 410-516-2345
Fax: 410-516-4314

This transmission may contain privileged and confidential information. Be 
advised that any disclosure, copying, distribution or other use of this 
information is strictly prohibited.

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