Remember that benzaldehyde in aqueous solution (like nitric acid) is in equilibrium with the hydrate. The hydrate is similar to the acetal - and the acetal is an o-p director (not m), and activating. So the fastest reaction is with the hydrate at the o and p positions!
Does benzaldehyde mix well with water? During my experiment, I observed two layers form, so I thought the reason for the failure was because benzaldehyde was not very soluble in water. Thus it couldn't get into the reaction mixture, perhaps...? What should I do to facilitate the process?
Remember that benzaldehyde in aqueous solution (like nitric acid) is in equilibrium with the hydrate. The hydrate is similar to the acetal - and the acetal is an o-p director (not m), and activating. So the fastest reaction is with the hydrate at the o and p positions!
Does benzaldehyde mix well with water? During my experiment, I observed two layers form, so I thought the reason for the failure was because benzaldehyde was not very soluble in water. Thus it couldn't get into the reaction mixture, perhaps...? What should I do to facilitate the process?
It seemes strange even so, I think there is something wrong here. Read the wikipedialink I provided its just not possible with just nitric acid and benzaldehyde.
It seemes strange even so, I think there is something wrong here. Read the wikipedialink I provided its just not possible with just nitric acid and benzaldehyde.
I am surpriced that you can make o-nitration of benzaldehyde, main product should be m-nitro? It sounds very strange, at my first workplace they made a lot of nitrations and one compound we wanted was the o-nitrobenzaldehyde, we made it through ozonolysis of o-nitrostilbene, it was not possible to nitrate benzaldehyde directly.
Yes, and that was why I was astounded to see those procedures in a published thesis. It has something to do with the carbonyl oxygen which perhaps might form a six membered transition state. But what I am curious about is that even if I did not get o-nitrobenzaldehyde, I should have gotten some product as a nitration product. (or at least some "solid" from a side reaction, perhaps) Even if those who wrote those theses were mistaken for the o-nitration, they should have seen something that made them write "precipitated solid" and 90% or 91% as their yield...
I am surpriced that you can make o-nitration of benzaldehyde, main product should be m-nitro? It sounds very strange, at my first workplace they made a lot of nitrations and one compound we wanted was the o-nitrobenzaldehyde, we made it through ozonolysis of o-nitrostilbene, it was not possible to nitrate benzaldehyde directly.
Yes, and that was why I was astounded to see those procedures in a published thesis. It has something to do with the carbonyl oxygen which perhaps might form a six membered transition state. But what I am curious about is that even if I did not get o-nitrobenzaldehyde, I should have gotten some product as a nitration product. (or at least some "solid" from a side reaction, perhaps) Even if those who wrote those theses were mistaken for the o-nitration, they should have seen something that made them write "precipitated solid" and 90% or 91% as their yield...
Remember that benzaldehyde in aqueous solution (like nitric acid) is in equilibrium with the hydrate. The hydrate is similar to the acetal - and the acetal is an o-p director (not m), and activating. So the fastest reaction is with the hydrate at the o and p positions!
There is an preference for ortho with benzyl alcohols - a nitrate ester is possible involved with intramolecular nitration at the o position.
Just be careful - when I did some of this chemistry decades ago, the nitrate esters can lower your blood pressure - even being very careful it can be noticeable.
This is the reverse of amines - the amine group is activating o,p; but if protonated to ammonium is deactivating and m.
Remember that benzaldehyde in aqueous solution (like nitric acid) is in equilibrium with the hydrate. The hydrate is similar to the acetal - and the acetal is an o-p director (not m), and activating. So the fastest reaction is with the hydrate at the o and p positions!
There is an preference for ortho with benzyl alcohols - a nitrate ester is possible involved with intramolecular nitration at the o position.
Just be careful - when I did some of this chemistry decades ago, the nitrate esters can lower your blood pressure - even being very careful it can be noticeable.
This is the reverse of amines - the amine group is activating o,p; but if protonated to ammonium is deactivating and m.
Have you done a thorough litterature-search on this matter? The two references with the alkoxygroups are different and this chemistry can not be used for the non-substituted benzaldehyde. If you do find a catalyst it would be of great value for the industry.
Have you done a thorough litterature-search on this matter? The two references with the alkoxygroups are different and this chemistry can not be used for the non-substituted benzaldehyde. If you do find a catalyst it would be of great value for the industry.
Having recently purchased ortho-nitrobenzaldehyde, I can say that the commercial material was of good quality for our work.
I'm sorry, but I don't seem to understand what you mean. Do you mean that you have succeeded in the aforementioned ortho-nitration process, or is it just that the purchased ortho-nitrobenzaldehyde was of good quality?
Having recently purchased ortho-nitrobenzaldehyde, I can say that the commercial material was of good quality for our work.
I'm sorry, but I don't seem to understand what you mean. Do you mean that you have succeeded in the aforementioned ortho-nitration process, or is it just that the purchased ortho-nitrobenzaldehyde was of good quality?
I am surpriced that you can make o-nitration of benzaldehyde, main product should be m-nitro? It sounds very strange, at my first workplace they made a lot of nitrations and one compound we wanted was the o-nitrobenzaldehyde, we made it through ozonolysis of o-nitrostilbene, it was not possible to nitrate benzaldehyde directly.
I am surpriced that you can make o-nitration of benzaldehyde, main product should be m-nitro? It sounds very strange, at my first workplace they made a lot of nitrations and one compound we wanted was the o-nitrobenzaldehyde, we made it through ozonolysis of o-nitrostilbene, it was not possible to nitrate benzaldehyde directly.
I wright this again, have you read the wikipedia article on nitration of benzaldehyde? You get mainly the m-isomere just as would be expected. If they use some kind of catalyst or special solvent then maybe something else is possible but it seems not to be what you are using?
Yes I read the wiki article and several other sources, and I know well that the m-isomer should be the major product. But it says in the sources I mentioned above that with only nitric acid ortho-nitration is possible. So that's why I brought this matter to the forum: how did they do that, and why couldn't I get it? So you've said that the method in the first source (2-nitrobenzaldehyde synthesis) is wrong. I get the message. I'll try again with different conditions or perhaps an additional catalyst or reagent. Thank you anyway
I wright this again, have you read the wikipedia article on nitration of benzaldehyde? You get mainly the m-isomere just as would be expected. If they use some kind of catalyst or special solvent then maybe something else is possible but it seems not to be what you are using?
Yes I read the wiki article and several other sources, and I know well that the m-isomer should be the major product. But it says in the sources I mentioned above that with only nitric acid ortho-nitration is possible. So that's why I brought this matter to the forum: how did they do that, and why couldn't I get it? So you've said that the method in the first source (2-nitrobenzaldehyde synthesis) is wrong. I get the message. I'll try again with different conditions or perhaps an additional catalyst or reagent. Thank you anyway
I wright this again, have you read the wikipedia article on nitration of benzaldehyde? You get mainly the m-isomere just as would be expected. If they use some kind of catalyst or special solvent then maybe something else is possible but it seems not to be what you are using?
I wright this again, have you read the wikipedia article on nitration of benzaldehyde? You get mainly the m-isomere just as would be expected. If they use some kind of catalyst or special solvent then maybe something else is possible but it seems not to be what you are using?
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Does benzaldehyde mix well with water? During my experiment, I observed two layers form, so I thought the reason for the failure was because benzaldehyde was not very soluble in water. Thus it couldn't get into the reaction mixture, perhaps...? What should I do to facilitate the process?
Does benzaldehyde mix well with water? During my experiment, I observed two layers form, so I thought the reason for the failure was because benzaldehyde was not very soluble in water. Thus it couldn't get into the reaction mixture, perhaps...? What should I do to facilitate the process?
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Paper can be downloaded.
Paper can be downloaded.
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Yes, and that was why I was astounded to see those procedures in a published thesis. It has something to do with the carbonyl oxygen which perhaps might form a six membered transition state.
But what I am curious about is that even if I did not get o-nitrobenzaldehyde, I should have gotten some product as a nitration product. (or at least some "solid" from a side reaction, perhaps) Even if those who wrote those theses were mistaken for the o-nitration, they should have seen something that made them write "precipitated solid" and 90% or 91% as their yield...
Yes, and that was why I was astounded to see those procedures in a published thesis. It has something to do with the carbonyl oxygen which perhaps might form a six membered transition state.
But what I am curious about is that even if I did not get o-nitrobenzaldehyde, I should have gotten some product as a nitration product. (or at least some "solid" from a side reaction, perhaps) Even if those who wrote those theses were mistaken for the o-nitration, they should have seen something that made them write "precipitated solid" and 90% or 91% as their yield...
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There is an preference for ortho with benzyl alcohols - a nitrate ester is possible involved with intramolecular nitration at the o position.
Just be careful - when I did some of this chemistry decades ago, the nitrate esters can lower your blood pressure - even being very careful it can be noticeable.
This is the reverse of amines - the amine group is activating o,p; but if protonated to ammonium is deactivating and m.
There is an preference for ortho with benzyl alcohols - a nitrate ester is possible involved with intramolecular nitration at the o position.
Just be careful - when I did some of this chemistry decades ago, the nitrate esters can lower your blood pressure - even being very careful it can be noticeable.
This is the reverse of amines - the amine group is activating o,p; but if protonated to ammonium is deactivating and m.
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I'm sorry, but I don't seem to understand what you mean. Do you mean that you have succeeded in the aforementioned ortho-nitration process, or is it just that the purchased ortho-nitrobenzaldehyde was of good quality?
I'm sorry, but I don't seem to understand what you mean. Do you mean that you have succeeded in the aforementioned ortho-nitration process, or is it just that the purchased ortho-nitrobenzaldehyde was of good quality?
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Yes I read the wiki article and several other sources, and I know well that the m-isomer should be the major product. But it says in the sources I mentioned above that with only nitric acid ortho-nitration is possible. So that's why I brought this matter to the forum: how did they do that, and why couldn't I get it?
So you've said that the method in the first source (2-nitrobenzaldehyde synthesis) is wrong. I get the message. I'll try again with different conditions or perhaps an additional catalyst or reagent. Thank you anyway
Yes I read the wiki article and several other sources, and I know well that the m-isomer should be the major product. But it says in the sources I mentioned above that with only nitric acid ortho-nitration is possible. So that's why I brought this matter to the forum: how did they do that, and why couldn't I get it?
So you've said that the method in the first source (2-nitrobenzaldehyde synthesis) is wrong. I get the message. I'll try again with different conditions or perhaps an additional catalyst or reagent. Thank you anyway
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