Sciencemadness Discussion Board

Catalyzing: n-butylamine vs Di-n-butylamine

legnanu - 22-8-2012 at 06:57

n-butylamine (CAS: 109-73-9) vs Di-n-butylamine (CAS: 111-92-2)

Anyone know the differences when catalyze?

I mean ... would use the same proportion and catalyzing be done in less time?
Or rather should use another ratio for the same effect (half the proportion to be "Di"?)

Someone has to answer for real knowledge? :D

Hexavalent - 22-8-2012 at 07:11

What reaction are you catalysing?

Are you reacting benzaldehyde and nitroethane to produce phenyl-2-nitropropene, by any chance?

legnanu - 22-8-2012 at 08:24

(I apologize to the administrator, but I do not know where this thread has moved)

hehe ... I did it a while ... Yes, many times :))

But now I do not want to do it, but try to go a little bit into it.
I am writing a small "book" and what I intend to "improve" some typical reactions theoretical.
Or so at least I try;)

I theoretical calculations with cyclohexylamine, di-n-butylamine, etc ....

I hope you understand my English .... write using web translators is not easy;)

Nicodem - 22-8-2012 at 08:43

Quote: Originally posted by legnanu  
(I apologize to the administrator, but I do not know where this thread has moved)

Unanswerable and vague questions, as well as posts lacking any references, should only be posted in the Beginnings section. Read the forum guidelines.
Quote:
"Si quieres ser sabio, aprende a interrogar razonablemente, a escuchar con atención, a responder serenamente y a callar cuando no tengas nada que decir"

I suggest you to take advice from your own signature and ask reasonable questions, with all the required information and references, rather than babble nonsense. How on earth is anybody going to answer when you don't even say which reaction you talk about?

legnanu - 22-8-2012 at 08:50

You're absolutely right and I apologize.

I wrote the post worrying about my translating and not the content.

Excuse me please.

legnanu - 22-8-2012 at 08:55

Quote: Originally posted by Hexavalent  
What reaction are you catalysing?

Are you reacting benzaldehyde and nitroethane to produce phenyl-2-nitropropene, by any chance?


Do you know how to operate in this reaction do you say?
I am referring to difference between di-n-butylamine and n-butylamine.

Can you tell me something about this?

thanks

[Edited on 22-8-2012 by legnanu]

Hexavalent - 22-8-2012 at 08:56

You still haven't told us what you're actually doing.

legnanu - 22-8-2012 at 08:59

Quote: Originally posted by legnanu  
Quote: Originally posted by Hexavalent  
What reaction are you catalysing?

Are you reacting benzaldehyde and nitroethane to produce phenyl-2-nitropropene, by any chance?


Do you know how to operate in this reaction do you say?
I am referring to difference between di-n-butylamine and n-butylamine.

Can you tell me something about this?

thanks

[Edited on 22-8-2012 by legnanu]


------> phenyl-2-nitropropene <------

Hexavalent - 22-8-2012 at 10:27

At least have the courtesy to show what you have edited to avoid making others look stupid.

I have an idea, but, first, why don't you do a little research of your own and tell us what you think?

legnanu - 22-8-2012 at 11:35

Do not do anything right here so it seems ...

Well ... I edited my question above (for trying to do better) while you were answering me and I have not noticed, I'm sorry. As I finish editing it to fix it you've already answered quickly.
Excuse me once again ...

And reading some of your posts around the forum, I want you to know you're not stupid and you do not seem to be just the opposite

Returning to the thread post... what I have investigated and read "seems" it is not so powerful catalyst and as quickly as cyclohexylamine but seems to be more than the n-butylamine.

Could you tell me (by example of 1-Phenyl-2-nitropropene as mentioned before) the differences would have to use n-butylamine or di-n-butylamine?

As I think it would take less amount of catalyst but cost the same time?


P.D: Thanks for all and excuse my beginning with the previous posts. As I said before the administrator, I am very aware of language and translation, and this has affected the content. Sorry Hexavalent... I´ll try to be more accurate and correct in my text / question next time.

Hexavalent - 22-8-2012 at 13:06

I believe that the di-n-butylamine will work as a catalyst, it may be possible just use half the molar amount specified for the n-butylamine and keep the reaction conditions and time the same.

Here is what should happen;



In this reaction, the base (the butylamine) deprotonates nitroethane to form a resonance stabilized anion. This anion nucleophilically adds to the aldehyde forming a beta nitro alcohol, which is subsequently dehydrated to yield the nitroalkene.

This reaction is known as a nitroaldol reaction.

The best way to find out is to try it on a small scale and just see what happens; experimentation is the core of the scientific method.





[Edited on 22-8-2012 by Hexavalent]

Nicodem - 22-8-2012 at 13:33

Quote: Originally posted by Hexavalent  
I believe that the di-n-butylamine will work as a catalyst, just use half the molar amount specified for the n-butylamine and keep the reaction conditions and time the same.

Where did you get that about half amount? What is the reference where secondary amines were found twice as efficient?
Quote:
In this reaction, the base (the butylamine) deprotonates nitroethane to form a resonance stabilized anion. This anion nucleophilically adds to the aldehyde forming a beta nitro alcohol, which is subsequently dehydrated to yield the nitroalkene.

That is not the way the mechanism of this catalysis is generally considered. The primary amine is not just a base. It is also a catalyst. The mechanism was already discussed on this forum, so UTFSE for details. What you described is the mechanism of another reaction, the Henry reaction followed by elimination.
Quote:
This reaction is known as a nitroaldol reaction.

No, the Henry reaction is sometimes called as the nitroaldol reaction, but this one is called the Knoevenagel condensation.
Quote:
The best way to find out is to try it on a small scale and just see what happens; experimentation is the core of the scientific method.

And one hour of literature work can save one week of lab work.

Hexavalent - 22-8-2012 at 13:45

Quote:
http://wavefunction.fieldofscience.com/2010/11/why-are-secon...

Mentions here that secondary amines are usually the most basic, the latter property being needed for this reaction. Perhaps, indeed, not twice as efficient, but a starting point nonetheless.

Quote: Originally posted by Nicodem  
That is not the way the mechanism of this catalysis is generally considered. The primary amine is not just a base. It is also a catalyst. The mechanism was already discussed on this forum, so UTFSE for details.

What you described is the mechanism of another reaction, the Henry reaction followed by elimination.



OK, thanks; I appreciate the correction. Thanks for pointing that one out.

Overall, what would you answer to the OP's question, Nicodem?



[Edited on 22-8-2012 by Hexavalent]

legnanu - 23-8-2012 at 08:11

Then I'm just like the beginning not knowing if would catalyze ...

I will continue looking around (via UTFSE nothing appears :().

thanks

J.