From: "Nail, John" <jnail**At_Symbol_Here**OKCU.EDU>
Subject: Re: [DCHAS-L] Unexpected Reaction - asking for your collective wisdom
Date: Fri, 1 May 2015 18:13:50 +0000
Reply-To: DCHAS-L <DCHAS-L**At_Symbol_Here**MED.CORNELL.EDU>
Message-ID: D1692A3E.9298%jnail**At_Symbol_Here**

Except for burning it and possibly reacting with nitric acid to form RNOx species,  acetic acid doesn't oxidize. To emphasize this point, I'll pretend that this is a discussion with one of my organic chem students and ask the student 'if acetic acid oxidizes, what is the oxidation product and what is the mechanism for the formation of the oxidation product?'

One possibility is a bromination of the acetic acid – this would imply that a strong acid such as hydrobromic was present.

Could the acetic acid have been contaminated with acetone? If so, the acetic acid catalyzed the bromination of acetone to bromoacetone – this is a standard Gen Chem 2 kinetics experiment.

Another possibility is the Hell-Volhardt-Zelisky reaction which occurs if elemental phosphorous, PCl3 or PBr3  is present (P + Br2 --> PBr3)

Hope that this helps.
John Nail
Professor of Chemistry
Oklahoma City University

From: Russell Vernon <russell.vernon**At_Symbol_Here**UCR.EDU>
Reply-To: DCHAS-L <dchas-l**At_Symbol_Here**MED.CORNELL.EDU>
Date: Friday, May 1, 2015 12:36 PM
To: "DCHAS-L**At_Symbol_Here**MED.CORNELL.EDU" <dchas-l**At_Symbol_Here**MED.CORNELL.EDU>
Subject: [DCHAS-L] Unexpected Reaction - asking for your collective wisdom

Dear Fellow Chemists,


Here’s a description of an unexpected reaction. Please speculate as to the chemical root causes…


A person:

1.    measured out 400 mL of acetic acid and transferred it to an open mouth flask

2.    measured 100 mL of bromine and transferred part of that to the same flask

3.    realizing that the flask into the liquids were being transferred was not large enough

4.    retrieved a 1 L flask and transferred the partial mixture into this larger flask

5.    then poured the rest of the bromine into the 1L flask


Here’s the unexpected part…

=B7         A second or two after the final aliquot of bromine was added the mixture erupted, forcing the contents out of the flask with significant velocity


We have assumed that there was some easily oxidized contaminant in the 1 L flask which was not noticed by the person involved…


Does anyone have a history with this material that would possible provide alternate explanations?


If you prefer to communicate off-line, please do.







Russell Vernon, Ph.D.
Environmental Health & Safety
University of California, Riverside
900 University Ave
Riverside, CA 92521
Direct (951) 827-5119
Admin (951) 827-5528
Fax (951) 827-5122

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