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Previous by Date: Subject: Re: [DCHAS-L] Safer Diels-Alder reaction Date: Friday, July 19, 2019 at 12:56:44 PM Author: "Stuart, Ralph" <Ralph.Stuart**At_Symbol_Here**KEENE.EDU>

Next by Date: Subject: Re: [DCHAS-L] Safer Diels-Alder reaction Date: Fri, 19 Jul 2019 18:02:44 +0000 Author: Yaritza Brinker

Ralph,

I would submit that it's necessary to understand the fundamental chemistry
before you look to identify substitutions for chemicals and processes.
While professor Denlinger knows the chemistry, her students do not, yet.
The Diels-Alder reaction is part of that fundamental knowledge base.
Performing this reaction in an academic setting can allow for the following
fundamental chemical safety concepts to be taught and reinforced:

- Hazardous materials handling (primary flammables and exposure
considerations)
- Reaction thermodynamics
- Reaction kinetics and reaction control
- Waste management

Likewise, Lee pointed out that the creation of DCPD is essentially an
impurity in the reaction so you can also throw in quality assurance lessons
too which are, at times, applicable to the overall safety message.

WRT your second point, there are indeed a lot of assumptions in
"highly-supervised classroom..." A faculty:student ratio of 1:16 may not
provide effective oversight and more oversight bodies may be needed.
Likewise, if there is limited hood space for containment/ventilation, then
the concept of "good containment" goes out the window as well.

While the Diels-Alder reaction has been around for 90+ years, I would
venture a guess that it was discovered in what we, today, would consider a
safety vacuum and without assessment. However, in order to know where you
want to go (i.e. 21st century risk assessment) you absolutely must know
where you've been (fundamental concepts of chemical safety). If you don't
know the fundamentals, you're driving blind. The Diels-Alder reaction opens
up a lot of opportunity to teach integrated chemical safety.

H

-----Original Message-----
From: ACS Division of Chemical Health and Safety On
Behalf Of Stuart, Ralph
Sent: Friday, July 19, 2019 11:57 AM
To: DCHAS-L**At_Symbol_Here**PRINCETON.EDU
Subject: Re: [DCHAS-L] Safer Diels-Alder reaction

> >What better place to teach chemical safety and how to handle exothermic
reactions than in a highly-supervised classroom with limited quantities and
good containment?... I would encourage you not to miss a great opportunity
to teach safety to the next generation.
>
I have two concerns with these sentiments.

1) As I recall, the first step in hazard control for safer chemistry is to
identify substitutions for hazardous chemicals and/or processes that can
lessen the hazard. The original question is an excellent example of taking
that step. In terms of safety education, this step can be enhanced by
informing students about alternate lab processes and why they are not being
used.

2) Also there are a lot of assumptions in "highly-supervised classroom with
limited quantities and good containment". An organic chemistry lab class of
16 or so is a difficult place to provide effective oversight of people who
are new to both the science and the lab skills being used. At Keene State,
most chemistry majors participate in hands-on research experiences that are
closely supervised by faculty. This seems like a better place to learn how
to handle exothermic reactions than in a group setting.

In sum, the idea that the risk decisions made 90 years ago should not be
reconsidered today seems to me to be the opposite of a 21st century safety
education.

- 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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