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Subject: [DCHAS-L] Is Swiss cheese helpful for understanding accident causation?
Date: Friday, April 30, 2021 at 12:57:17 PM
Author: Jessica Martin <jessica.a.martin**At_Symbol_Here**UCONN.EDU> 		Next by Date:
Subject: Re: [DCHAS-L] Is Swiss cheese helpful for understanding accident causation?
Date: Sat, 1 May 2021 20:35:48 +0000
Author: "Reinhardt, Peter"

From: Natalie Merrill <namerrill**At_Symbol_Here**gmail.com>
Subject: Re: [DCHAS-L] Explosive synthesis scaleup question
Date: Sat, 1 May 2021 10:04:28 -0700
Reply-To: ACS Division of Chemical Health and Safety <DCHAS-L**At_Symbol_Here**Princeton.EDU>
Message-ID: CADq5LmQqGa+gh_TvDt=vsezYw9iRkeqX=67os3caFj7idzHJyg**At_Symbol_Here**mail.gmail.com
In-Reply-To


Dear Jack, are you forwarding these replies to the researcher who contacted you? I hope you do! Thanks for a good question. Hopefully in answering, a lot of risk and expense can be taken out of the equation for the scale-up in question.

One of the basic but relevant mistakes to avoid in scale up involving explosive or catalytic materials is "rounding error" in the initial calculations. In Excel or any other calculator, a rounding error upon scaling up can lead rather quickly to gross inaccuracies which can be dangerous.

Beware of "proper scientific notation," and be advised of when it is proper.

Multiple step synthesis with purification at every step can limit the magnitude of the error allowing trained "experts" to continue to overlook the impact of the rounding error.

Another source of explosion are the surface to volume ratio differences in scaling up. When not accustomed to calculating for adventitious moisture or oxygen, these realities can rear their heads in surprising ways. The "thermodynamics of scale" suddenly become much less mysterious if taking all critical quantities into account.


Natalie


On Tue, Apr 27, 2021 at 10:26 AM Jack Reidy <jreidy2**At_Symbol_Here**stanford.edu> wrote:

All,

Recently we had a researcher contact us with two questions: testing explosive properties of a novel compound, and scaling up from a 100 mg synthesis to (eventually, with intermediate steps) a 5 g synthesis. The compound in question is, as I mentioned, novel, but I believe the proper name would be iodomethyl diazirine. To our knowledge, we don't have anyone on campus with the equipment to do sensitivity tests or the like, so would anyone have guidance on finding appropriate facilities? Additionally, does anyone have experience with researchers doing syntheses with this sort of compound at this sort of scale? If so, what sort of facilities and equipment would you say are necessary to perform the synthesis safely? Additionally, do you know of any faculty whose labs work with diazirines in particular? Thank you!

Sincerely,

Jack Reidy (he/him)

Research Safety Specialist, Assistant Chemical Hygiene Officer

Environmental Health & Safety

Stanford University

484 Oak Road, Stanford, CA, 94305

Tel: (650) 497-7614

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Natalie Merrill
namerrill**At_Symbol_Here**gmail.com
--- For more information about the DCHAS-L e-mail list, contact the Divisional membership chair at membership**At_Symbol_Here**dchas.org Follow us on Twitter **At_Symbol_Here**acsdchas

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