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Previous by Date: Subject: Re: [DCHAS-L] 3 more thoughts on safety shower drainage Date: Friday, October 5, 2018 at 8:53:17 AM Author: Jeffrey Lewin <jclewin**At_Symbol_Here**MTU.EDU> |
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Here it is:
https://pubs.acs.org/isbn/9780841229600
You can download Frankie's excellent chapter as a PDF.
https://pubs.acs.org/doi/pdf/10.1021/bk-2014-1163.ch003
Someone told me this: "Reaction Scale-Ups are dangerous due to two factors that are both present in most experiments: a) the cube/square relationship (volume and
mass increases by r^3, whereas, surface area increased by r^2, so the ability to control a reaction mixture by cooling the vessel decreases when scaled-up) and b) reaction rates have an exponential relationship to the temperature (the Arrhenius equation, k=A*e^(-Ea/R*T)).
So, a scaled-up exothermic reaction vessel is likely to overheat due to its relatively smaller surface area, and this overheating causes the reaction to run faster, which causes the mixture to heat further, which causesÉ.boom!"
Pete
From: ACS Division of Chemical Health and Safety [mailto:DCHAS-L**At_Symbol_Here**PRINCETON.EDU]
On Behalf Of Frankie Wood-Black
Sent: Thursday, October 04, 2018 12:16 PM
To: DCHAS-L**At_Symbol_Here**PRINCETON.EDU
Subject: Re: [DCHAS-L] Papers on risks of scaling up reactions
Sorry for the late reply - but there is an ACS symposium series book that looks at the issues surrounding scale up. Some of the risks that are harder to classify include:
1) If exothermic - the increases may lead to temperature changes that may have to be controlled at higher volumes - which in turn may lead to other issues. Similarly, if the reaction is endothermic.
2) Many times the wastes on a small scale are not apparent, as you scale up you may encounter waste streams (this was one of the reasons, we did multi-step scale-ups to see what wastes were generated and helped us to better quantify if
that was the specific pathway we wanted to commercialize.
3) And, then there are the reaction vessel requirements - as you commercialize there are potential cost/benefit - safety considerations that have to be accounted for.
Suggest you check out the symposium book.
Frankie Wood-Black, Ph.D., REM, MBA
Principal - Sophic Pursuits
NOTE - ADDRESS CHANGE - Mailing Address - PO Box 433, Tonkawa, OK 74653
email address fwoodblack90**At_Symbol_Here**gmail.com
580-761-3703
On Tue, Sep 25, 2018 at 10:09 AM Jeffrey R. Cogswell <Jeffrey.R.Cogswell**At_Symbol_Here**dartmouth.edu> wrote:
Hello
I'm currently working on a safety talk about RAMP and decided to include a section on "RAMPing up Reactions"
It was discussed at ACS that scaling up reactions is a under-stated danger in many chemistry laboratories.
Does anyone have any suggestion for articles that talks about or quantifies the risks of increasing the yield in chemical reactions?
For example: https://ac.els-cdn.com/S1871553213006178/1-s2.0-S1871553213006178-main.pdf?_tid=672cf49d-0170-4ff1-8b06-85bc88bda807&acdnat=1537887055_4baf3ea46cec9ef7b4cb51c2aba76bf8 I found very informative and it would be great to find more sources.
Thanks
Jeffrey R. Cogswell, Ph.D.
Chemical Inventory and Laboratory Resource Center Technician, EHS
37 Dewey Field Road, HB 6216
Hanover, New Hampshire 03755
http://www.dartmouth.edu/~ehs/
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