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Previous by Date: Subject: [DCHAS-L] ACS Election: YCC wants to Catalyze the Vote Date: Saturday, October 13, 2018 at 10:49:04 AM Author: DCHAS Membership Chair <membership**At_Symbol_Here**DCHAS.ORG> |
Next by Date: Subject: Re: [DCHAS-L] sodium hydride solution Date: Sun, 14 Oct 2018 21:52:41 -0400 Author: Peter Zavon |
Certainly true. I would go so far as to say that if the researcher does not understand this simple acid-base reaction that we would expect a student in level 2 organic chemistry to understand, then they should not undertake the process. The issue of scale also seems to have not even been considered: this reaction will be exothermic and could run away if the scale is not contemplated with relation to cooling the mixture.
My read of this is that the researcher is not a chemist. If so, then I cannot emphasize enough that they should consult a chemist who has used sodium hydride before, in advance of even buying it, and WELL before they decide to clean up a spill with water! Believe it or not, many chemists actually have training and expertise in handling dangerously reactive substances such as hydrides, metals, alkyllithiums and so forth! As I like to say, we don`t bite (very hard) and most chemists would (should) be willing to assist a non-expert in performing this process safely.
I am wondering if a certified safety professional should have to sign off on these substances, much like an engineer signs off that a bridge won`t collapse.... In the current situation, I wouldn't drive across that bridge until I had looked at it very carefully from all angles.
Paul
________________________________________
From: ACS Division of Chemical Health and Safety [DCHAS-L**At_Symbol_Here**PRINCETON.EDU] on behalf of davivid [davivid**At_Symbol_Here**WELL.COM]
Sent: October 11, 2018 12:17 PM
To: DCHAS-L**At_Symbol_Here**PRINCETON.EDU
Subject: Re: [DCHAS-L] sodium hydride solution
Ellen
I don't know what reading is being referred to here, but I think there
may have been some miscommunication. Sodium hydride will certainly react
with 2-propanol. In fact, it is a good base to use to generate solutions
of alkoxide. The sodium hydride is insoluble, reacting at it's surface
to deprotonate the alcohol and generate the alkoxide.
See for example...
https://www.masterorganicchemistry.com/2014/10/24/the-williamson-ether-synthesis/
Sodium hydride is usually supplied as a dispersion of the solid in
mineral oil to avoid reaction with atmospheric moisture. See the
following for usage...
https://onlinelibrary.wiley.com/doi/10.1002/9780471264194.fos09197.pub4
https://pubs.acs.org/doi/abs/10.1021/op200114t?src=recsys&journalCode=oprdfk
I hope this helps
Dave Lane
Principal
Clavis Technology Development
On 10/10/18 12:39 PM, Ellen M. Sweet wrote:
> Hi everyone,
> I have a researcher who is proposing to make a solution of 2-propanol and sodium hydride.
>>From what I'm reading the NaH will not react with the propanol, but that this needs to be done slowly and under nitrogen.
>
> Any suggestions on what this setup would like and how to add the NaH?
> Thanks in advance.
>
> Ellen
>
> Ellen Sweet
> Laboratory Ventilation Specialist
> Department of Environmental Health and Safety, Cornell University
> American Chemical Society, Division of Chemical Health and Safety
> 315-730-8896
>
>
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