Patricia,
I think it's useful here to separate the issue of the reaction from the issue of storing the waste that it produces. By definition, if two chemicals react exothermically,
then they would be deemed incompatible in scenarios where uncontrolled mixing might occur. This does not, however, exclude the possibility that they can be safely mixed in a properly designed experiment. As Tammy mentioned, the chemists proposing this should
be able to articulate why they've chosen these reagents and solvents, and should have enough knowledge of the reaction mechanism to have some confidence that the reaction will proceed as intended. In my experience, the area where chemists are more likely to
struggle is in understanding how to control the flow of heat in the reaction. You can probably get away with that if you're running small scale reactions immersed in a cooling bath, but this knowledge is critical when scaling up a reaction, or running an exothermic
reaction that needs to be heated.
But, you asked about the waste. As Sammye and Mary Beth said, vented caps for nitric acid should be a given. The vented caps I'm familiar with are PTFE, and
would be compatible with the materials you mentioned, but as Tammy mentioned it's wise to ask the question rather than assume. Greglynn's suggestion of separating the organic and aqueous components is an excellent one. Many, if not most, organic reactions
will involve a neutralization/extraction step that will accomplish this incidentally, if not by design. I think it would be worth asking your chemists if this is also part of their process, what organic solvents they intend to use, and, as Dave and Yasin pointed
out, how they will control for gas and/or heat release during any neutralization steps.
If we haven't given you enough to think about, please reach back out!
Chris
________________________________
Christopher M. Kolodziej, Ph.D.
Chemical Hygiene Officer
UCLA Environment, Health & Safety
| Chemical Safety
Mobile: (310) 261-8611
Book a virtual appointment
From: ACS Division of Chemical Health and Safety <DCHAS-L**At_Symbol_Here**Princeton.EDU>
On Behalf Of Yasinalli Tamboli
Sent: Thursday, July 15, 2021 8:10 PM
To: DCHAS-L**At_Symbol_Here**Princeton.EDU
Subject: Re: [DCHAS-L] [External] [DCHAS-L] Nitric Acid Disposal
I am totally agree with Greglynn.
In addition please make sure to apply external cooling while quenching or neutralising.
Patience is best friend in such cases.
Apologies. I received a message that my previous email could not be delivered because I included an attachment.
Again, I strongly suggest neutralizing with sodium bicarbonate, and then storing. This is common practice for acidic/basic wastes. Additionally, leaving
a waste container open/vented is against OSHA policy, as waste should always be neutralized and stored properly. If the waste contains any flammable substances, it must be stored with flammable waste. If the volumes produced are small enough, you can probably
separate the organic from the aqueous layer (post-neutralization) and store the flammable organic waste accordingly. It would probably be prudent to neutralize the waste after each experiment instead of collecting and waiting to neutralize in bulk.
Here is the link to a very helpful document that you can modify for your specific procedure and needs, including waste tracking. The document also contains
links to specific references for neutralization and handling of nitric acid wastes.
As long as you remain calm, PPE up, and work in the hood with secondary containment in case of spill, you should be fine. Panic and stress yields accidents.
Greglynn Gibbs
Research Technologist & Lab Manager - Chemistry
Penn State Berks
106A Luerssen Building
Tulpehocken Road, P.O. Box 7009
Reading, PA 19610
Office: (610) 396-6363
http://www.bk.psu.edu
Again, I strongly suggest neutralizing with sodium bicarbonate, and then storing. This is common practice for acidic/basic wastes. Additionally, leaving a waste container open/vented
is against OSHA policy, as waste should always be neutralized and stored properly. If the waste contains any flammable substances, it must be stored with flammable waste. If the volumes produced are small enough, you can probably separate the organic from
the aqueous layer (post-neutralization) and store the flammable organic waste accordingly. It would probably be prudent to neutralize the waste after each experiment instead of collecting and waiting to neutralize in bulk.
I have attached a document that you can modify for your specific procedure and needs, including waste tracking. The document also contains links to specific references for neutralization
and handling of nitric acid wastes.
As long as you remain calm, PPE up, and work in the hood with secondary containment in case of spill, you should be fine. Panic and stress yields accidents.
Greglynn Gibbs
Research Technologist & Lab Manager - Chemistry
Penn State Berks
106A Luerssen Building
Tulpehocken Road, P.O. Box 7009
Reading, PA 19610
Office: (610) 396-6363
http://www.bk.psu.edu
I would suggest a vented cap on the waste bottle.
S-
On 7/15/2021 9:33 AM, Patricia Leach wrote:
Hello,
I had a question from one of the organic chemists here about how to store the waste from a nitration using nitric acid in a dichloromentane/acetic acid solvent. He says there are several examples of this nitration in the literature, but I am still wary.
While the reaction is open to the atmosphere, I am worried about storing it until it can be disposed of. Any advice would be greatly appreciated.
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Patricia Leach
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Environmental Health and Safety Coordinator
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Campus Operations and Safety
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P: 903.468.3278
C: 316.644.8255
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Mail: P.O. Box 3011, Commerce, TX 75429
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