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Author: Subject: Precipitate on Henry-Reaction with ethylenediamine!?
Iodomaster
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[*] posted on 18-10-2010 at 16:18
Precipitate on Henry-Reaction with ethylenediamine!?


I tried http://www.erowid.org/archive/rhodium/chemistry/edda.html with 4-Iodo-2,5-Dimethoxybenzaldehyd and MeNO2 as substrate, EtOH as solvent and ethylenediamine freebase (fresly destilled) as catalyst.

An unknown voluminous white precipitate was formed first. I added a large amount extra EtOH and heated everything but it still didn't dissolve. :( I thought I had to throw everything away, but...

Because the ED was stinking I added some GAA aand wups.. all the strange precipitate redissolved and the solution turned dark orange. :) Will tell you the yield and make a TLC of the product tomorrow.

In the "reference" is mentioned that this also happens with Piperonal, EDDA, IPA and EtNO2... but may this a mistake and ED freebase was used!?

What may be this stange material?

[Edited on 19-10-2010 by Iodomaster]
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[*] posted on 19-10-2010 at 15:32


Not to be critical but you are basically saying: I didn't follow the procedure in the reference at all and something different happened, why did this happen?

It is very common in chemistry that if one deviates from a given procedure even slightly one can expect a very different result.

Next time try following the reference by making the EDDA first and use that as a catalyst and you might have fewer problems.

Quote: Originally posted by Iodomaster  

In the "reference" is mentioned that this also happens with Piperonal, EDDA, IPA and EtNO2... but may this a mistake and ED freebase was used!?

[Edited on 19-10-2010 by Iodomaster]


I highly doubt that is the case. You are the one that didn't follow the stated procedure. There is nothing that would lead anyone to believe that the author did anything other than what they claimed. Maybe the white precipitate was just benzaldehyde that became insoluble after you added the ethylenediamine. If you were a little more specific and described the exact procedure you followed better it would be easier to answer your questions.
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[*] posted on 22-10-2010 at 00:58


did you buffer the solution with 1eq (based on EDA) AcOH ? The report is done with EDDA not EDA freebase.
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