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Previous by Date: Subject: Re: [DCHAS-L] Information Needed Date: Friday, June 1, 2018 at 11:29:58 AM Author: Alan Hall <oldeddoc**At_Symbol_Here**GMAIL.COM>

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Ralph

Your question raises an issue we have been struggling with for years. 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. The will not perform a hazard analysis or risk assessment. They should be working under the direct supervision of the former. If the former, 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."

Bretherick is currently the best source of reaction information. The Pistoia CSL database is attempting to meet this need but is a long way from doing so. CAMEO is limited, and other online resources do not really address reactions. The Elsevier HazMat Navigator was very good at this but died from lack of support by the publisher.

The problem of the sophisticated chemist using the information they should have is very real. The JOC paper:

Synthesis and Explosion Hazards of 4‰??Azido‰??L‰??phenylalanine
Mark B. Richardson,*,‰? Derek B. Brown,‰?Á Carlos A. Vasquez,‰? Joseph W. Ziller,‰? Kevin M. Johnston,‰?
and Gregory A. Weiss*,‰?

illustrates this point dramatically. The authors express surprise that 4‰??Azido‰??L‰??phenylalanine is potentially explosive. They fail to acknowledge the rule of thumb that as the N:C ratio increase beyond 1:5, the reactivity of the molecule increases proportionately. 4‰??Azido‰??L‰??phenylalanine has an N:C ratio of 4:9. (If you don't understand this rule of thumb you need to sit in on the workshop Harry and I present on highly reactive chemistry). The reactivity discussed elegantly in this MS is not a surprise.

So, YES, we need better resources for flagging reactive chemistry hazards - not just reactive chemical hazards - but the chemist must apply the knowledge and experience implicit in their profession to evaluate the unknown - not unknowable - in their research.

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-----Original Message-----
From: ACS Division of Chemical Health and Safety On Behalf Of Stuart, Ralph
Sent: Friday, June 1, 2018 5:11 AM
To: DCHAS-L**At_Symbol_Here**PRINCETON.EDU
Subject: [DCHAS-L] Triacetone triperoxide safety reference information

I am preparing a chem safety presentation for new summer research students here at KSC for next week and would like to include a discussion of the incident described at http://cenblog.org/the-safety-zone/2017/02/how-a-student-unintentionally-made-an-explosive-at-u-bristol/
The chemical involved in the incident is triacetone triperoxide (TATP), which has a fairly high public profile as a explosive that is easy to make.

I figured that the first step in discussing the hazards of TATP is to look for a SDS to review from the usual web sources. However, I was surprised to not find an SDS or other GHS information for this chemical at PubChem, Sigma/Aldrich or through a random Google search. ChemIdPlus returned an entry from ToxNet that indicated that TATP is a "Very sensitive explosive" but no other information that would help to put this designation into context.

Does anyone have suggestions about how a chemist developing a risk assessment of a process that involves acetone and hydrogen peroxide would discover the potential hazards associated with TATP in their work?

Thanks for any suggestions on this.

- 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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