biomechem
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Homogeneous catalysts in condensation, charge
I wonder if the compound I think of could be used as a catalysts in the following reactions.
R-CHO + R'-NO2 --base--> R(OH)-(R)NO2
According to the above rxn I know that it can be catalyzed just by NaOH. I found out that it is an old method and nowadays it's better to use teritary
amines.
R-CHO + R'-NO2 --base--> R=(R)NO2
On the other hand this reaction is catalyzed by primary amines, and what I discovered a moment ago secondary amines (piperidine).
What I think of is the possibility of using teritary diamines and primary diamines respectively. For example for each rxn I have 2 candidates.
I.
- N1,N1,N2,N2-tetramethylethane-1,2-diamine
- N,N'-tetramethyl substituted cadaverine
II.
- ethylenediamine
- cadaverine
I know nobody would want to do this due to extreme smell and much higher price, but I think it's good example to learn about some effects.
1. Would shorter chain amines be deactivated by first protonation? Or the molecules would be as active at second protonation?
2.Would it give any benefits to use diamines due to their complexation reactions ability?
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zed
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I once attempted to perform that condensation, using NaOH. I exactly executed the Org.Syn. procedure, that O.S. performed with Nitromathane to
produce B-Nitro-styrene. Excepting that I substituted Nitroethane.
http://www.orgsyn.org/demo.aspx?prep=CV1P0413
It produced zero % product.
In this matter, Six of one....doesn't necessarily equal a half a dozen of another.
There are lots of approaches to this reaction. The best approach, seems to vary according to substrates.
There is no real standard, that always gives best results.
In my estimation, the best approach to producing each nitroalkene, is the approach that has worked best for other chemists, in the past.
[Edited on 4-2-2018 by zed]
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biomechem
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Are you sure that your benzaldehyde was free of benzoic acid which deactivates catalyst- in this case base?
Don't get me wrong but I am not really interested in performing those synthesis at all.
I am just curious if diamines can make the product free of heavy metal ions by complexation rxn.
And if both of amine group will be active or the "double protonation" of the same molecule of diamine is not likely to happen.
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AvBaeyer
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Read the chapters in Organic Reactions vol 1 on the Knoevenagel and related reactions. The book is in the Forum Library. You will find the answers to
most of your questions. By the way, ethylenediamine diacetate is an effective catalyst.
AvB
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biomechem
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Are you saying that amine salts in these reactions can act as a catalysts too? When amine is in a salt form it cannot deprotonate nitrocompound. Could
you explain this to me?
BTW. Reaction is carried over 4 A MS?
AFAIK 3 A MS are enough to remove water (which is the compound affecting yield in condensations). What else is removed by 4 A pores?
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zed
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Weak acid.
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