Date: Tue, 6 Jul 2010 13:29:35 -0500
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: "Tsiakals, Nicholas John" <tsiakals**At_Symbol_Here**ILLINOIS.EDU>
Subject: Re: Sol-gel drying process
In-Reply-To: <33EBEF33F9721740B892CD7909B06EC3135248BA23**At_Symbol_Here**>

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Can’t say I’m familiar with the chemistry.=A0 Ev en so, I would turn these questions back at the lab(s) involved:

What were the intermediates/byproducts produced?< /span>

What was being evaporated at the hood? =A0At the oven?=A0

I question the hot plate boil-off and the convection oven fo r solvent.=A0 (If flammable atmospheres, then intrinsically safe electrical components required.)

(Did the convection oven vent to the room?)

Solvent/vapor recovery would be more robust – required at larger scale.

Does the person involved appreciate:=A0

Consequences were limited in this case by unwitting accidents of scale and access.

I realize this is unrefined, but this is where I would start with the ideas/questions.


From: DCHAS-L Discu ssion 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 recommendatio ns? 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 par ticulate 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 add ed resulting in the formation of AlOH particles from the organic precursor.  At this point, the composition was a viscous slurry. In order to redu ce the solvent content, the container was placed on a hot plate inside the fum e hood. The composition was heated (temperature unknown but estimated to be 70-80=B0C) 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 xxxx x and placed in a convection oven. I partially covered the container with a l id to allow venting and to prevent any swirling debris from contaminating the material. Oven temperature was set at 130=B0C and the general exhaust in th is room was turned on. My intent was to let the material dry overnight and I l eft for the day. When I returned the following day, I checked the oven and it w as 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 containe r 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< /a>

Homewood Campus Safety Office
3400 N. Charles Street

G04 Wyma n Park Bldg
Baltimore, MD 21218
Office: 410-516-2345
Fax: 410-516-4314

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