From: Anna Sitek <engl0131**At_Symbol_Here**umn.edu>
Subject: Re: [DCHAS-L] Triacetone triperoxide safety reference information
Date: Fri, 1 Jun 2018 15:19:17 -0500
Reply-To: ACS Division of Chemical Health and Safety <DCHAS-L**At_Symbol_Here**PRINCETON.EDU>
Message-ID: CA+=RE65Ce1AogXSBDC9G_5n=Qt7n9hn7DmNE=vxxzcFg1Hk9Wg**At_Symbol_Here**mail.gmail.com
In-Reply-To <79337668-6C7B-4507-8642-5FA92BF1471E**At_Symbol_Here**keene.edu>


I asked our JST lab safety officer's (graduate students in chemistry, chemical engineering & materials science) what they would tell or ask someone in their lab who was following a literature procedure with acetone as the reaction solvent and one part of the procedure calls for adding 30% H2O2 to remove some by products.

Given how common acetone and H2O2 are I assumed some students might not recognize the hazard because of their familiarity.

To my relief, all the responses indicated they immediately recognized a potential incompatibility, asked for further information, and required changes to the process. Some of the more comprehensive answers questioned what temperature, volume and concentration of H2O2 would be safe and referred to a literature reference explaining the acetone peroxide incompatibility applies to any solution containing more than 3% H2O2 and 7% acetone. (https://www.sciencedirect.com/science/article/pii/S1871553211000685).

Some of the comments:
" mixing a radical forming peroxide with a flammable organic solvent is generally dangerous "
" a flammable solvent and peroxide is an oxidizing agent, high temperature may cause a runaway reaction. "
" organics and peroxides are not safe to mix "
" combining a highly flammable solvent and a strong oxidizer, so it sounds like a flash fire / explosion risk"
" not advisable since they form explosive peroxides."
"So you are trying to make a bomb?"

On Fri, Jun 1, 2018 at 12:29 PM, Stuart, Ralph <Ralph.Stuart**At_Symbol_Here**keene.edu> wrote:
>Before we go there, however, we need to address an assumption implicit in the question: the level of sophistication of the chemist. Is the starting point a person with high-level understanding (and experience) with the reactions in question or a novice experimenting on their own? If the latter, then the discussion is moot.

As a entry level lab tech in the early 1980's in agronomy and industrial hygiene labs, I worked with both 30% H2O2 and acetone routinely. Fortunately, I was never inspired to mix them, but I don't think that means that the discussion is moot. I'm interested in how the lab population as a whole is best educated to assess the risks of the chemistry work they are doing. We know that Safety Data Sheets aren't designed to address process hazards but both the primary and compiled literature of known hazard is at best unsystematic and at worse baffling.

One alternative is:
> They should be working under the direct supervision of <a person with high-level understanding (and experience) with the reactions in question> then they should have the ability to recognize that A +B with a catalyst, can form D in addition to the product C they want. They get this knowledge on the journey to becoming a "sophisticated chemist."

As I read the SafetyZone report, the student was following a published procedure and had reviewed a risk assessment with his supervisor. The report suggests that's why he was able to recognize the formation of the TATP as the process proceeded. The SafetyZone has a variety of other reports when explosive chemicals were unintentionally generated; it's not clear if the risk assessments for these events addressed this possibility.

However, the larger point is that my experience in large research institutions is that many faculty in laboratory departments who supervise people working with these chemicals would not claim to be a "sophisticated chemist"; they are more likely to describe themselves as engineers, food scientists or biologists. These scientists will, however, use chemical reactions they find in the literature to further their research. My question is how do we best support this use case in the academic setting for hazard assessment purposes?

> I had a research student ask me yesterday what field of Chemistry studied how to learn what happened when you mixed two chemicals. It was such an interesting question. Specifically, he wanted to know how, when people wrote experimental procedures in papers, how did they know what to say - was it just experience.

One interesting challenge this question points to is that I have often heard inorganic chemists say that they don't know what "those organic chemists down the hall are doing" and vice versa. This might help raise the question of what the range of knowledge of a sophisticated chemist is expected to have. Will a student under their supervision be disallowed from pursuing a literature reaction their supervisor doesn't have experience with?

Thanks to everyone for their comments on this issue.

- Ralph

Ralph Stuart, CIH, CCHO
Environmental Safety Manager
Keene State College
603 358-2859

ralph.stuart**At_Symbol_Here**keene.edu

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--
Anna Sitek, CSP, CCHO
Research Safety Professional- College of Science & Engineering
Department of Environmental Health and Safety
University of Minnesota- TCEM
Lab Safety Resources www.z.umn.edu/labsafe
Joint Safety Team www.jst.umn.edu
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