Tough guys can run electrosynthesis

Here are some facts I took from one of my old lectures:

– Electrochemical alumunium production annually consumes more than 10% of electrical power in North America

– All oxidants and reductants accessible to organic chemists (chlorine, potassium permanganate, metallic sodium, hydrogen, to name a few) are produced in industry using electrochemistry

Shouldn’t these facts serve as reasons to use electrochemistry in order to run organic reactions directly, without involving all the waste associated with chemical reducing and oxidizing agents (we’re talking about chromium, lead, etc)? Think about it: if you pay electricity bills on time, electrons coming out of your electrical outlet will cost about 0.5 cents/mole… Curiously, the aforementioned considerations are not good enough to ensure widespread adoption of electrochemistry (otherwise there will be a lot more papers on this subject). The reason for this neglect lies in a steep barrier to entry into this field.

In the area of electrosynthesis, my lab has benefited tremendously from Tung Siu’s expertise. Tung was my first PhD student. When he came to my lab in 1999, Tung already had an undergraduate electrical engineering degree under his belt, which made it easy for him to engage in electrosynthesis. Tung was not intimidated…

Shockingly, I just realized that our last electrochemistry paper came out almost 10 years ago (http://pubs.acs.org/doi/abs/10.1021/jo048591p)… This work was done together with Tung and Christine Picard (now a Professor of Biology at Indiana U.: http://biology.iupui.edu/people/christine-picard). Ensuring continuity of projects is a big challenge in academic research and we somehow dropped the ball on electrochemistry in 2005… Now let’s fast forward to 2013. During this Christmas break I reasoned that it would be a perfect time to take our old Amel power supply off the shelf and see if that bad boy can still perform. Thankfully, Dmitry Pichugin was willing to help. Several years ago, Dmitry worked in my lab under the guidance of Igor Dubovyk. During his stay with us, Dmitry published a nice Angewandte paper together with Igor (http://onlinelibrary.wiley.com/doi/10.1002/ange.201100612/abstract). Of significance to our electrosynthesis aspirations, Dmitry is well versed in matters related to instruments and engineering (at the moment, he is working in our Departmental NMR facility). At 3:21pm, Dec. 27, Dmitry and I gave our Amel instrument a 2013 tune-up. Shono’s alpha-alkoxylation reaction (http://pubs.acs.org/doi/abs/10.1021/ja00848a020) was our test case. Do you want to see the easiest CH activation possible? Here it is! In the graphics shown below you will see our power supply and the reaction setup (2 graphite electrodes immersed into a methanolic solution of ethylpiperidine carbamate mixed with tetrabutylammonium tosylate as the supporting electrolyte). If you want, you can run this alkoxylation chemistry using graphite pencil inserts, it’s that simple. When I saw hydrogen bubbles at the cathode, I knew we were in business. Dmitry and I did not intend to push this reaction to completion. We ran it for 1.5 hours and just wanted to see the product. My PhD student Jeff St. Denis helped with the GC/MS analysis (thanks Jeff!). The most important outcome of this experiment is that things are working, we now have an updated standard operating procedure (even I can use this setup now), and I certainly hope that we will re-introduce electrochemistry back into our bag of tricks.

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GC/MS analysis of our crude reaction

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