From: lhlatimer**At_Symbol_Here**MINDSPRING.COM
Subject: Re: [DCHAS-L] Safer Diels-Alder reaction
Date: Fri, 19 Jul 2019 17:56:10 +0100
Reply-To: lhlatimer**At_Symbol_Here**MINDSPRING.COM
Message-ID: 992419083.4248.1563555370916**At_Symbol_Here**wamui-dingo.atl.sa.earthlink.net


Dr. Denlinger, 

Fear not, the procedure you mention has been done by undergraduates for over 50 years that I personally know of.  That being said, care is always of the essence as well as talking through issues with the students.  

I recommend when mixing the Cp and MA that it be done with a water bath/ice bath handy and condensers on the outgas side and under nitrogen i a hood.  And all glassware kept in the hood until rinsed with acetone in the hood.  

 One advantage to using smal/microl scale is that the cracking can be done as a group effort on a modest amount, and then several students can draw their needed sample, after the distillation is done.  Good opportunity to learn syringe techniques.  Mixing can then be done under controlled addition with a RT bath.  Reaction time is also shorter, and much less disposal material and cleanup.

Note that the Cp must be used immediately as it reverts rather easily to the diCp, which is literally an impurity in the product for the students to watch for and learn a bit about reactions.

Good luck, it works, can be easily controlled with lessons learned about safety.

Enjoy,

Lee


-----Original Message-----
From: "Denlinger, Kendra"
Sent: Jul 19, 2019 3:40 PM
To: DCHAS-L**At_Symbol_Here**PRINCETON.EDU
Subject: [DCHAS-L] Safer Diels-Alder reaction

Hello everyone,
I'm teaching an organic lab right now (my first time teaching this course), and we're supposed to do a Diels-Alder reaction in a few weeks. It's a reaction between cyclopentadiene and maleic anhydride, and the students are supposed to "crack" dicyclopentadiene to cyclopentadiene using a distillation with mineral oil, and then react cyclopentadiene with maleic anhydride in ethyl acetate (which is a very exothermic reaction). Long story short, the whole thing sounds like an accident waiting to happen. 

I know there has got to be a safer (and maybe even greener!) Diels-Alder reaction out there for organic lab students, but I don't know exactly where to look and thought maybe it would be a good question for all of you! I don't have a long time to search and test things, so if someone has a Diels-Alder procedure you use at your university that works and is safer, I would love to hear about it!

Thanks for any assistance!
Kendra Denlinger

Kendra Leahy Denlinger, Ph.D.

Adjunct Faculty

Department of Chemistry

Xavier University

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