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Author: Subject: P-Nitrophenol
Agari
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thumbup.gif posted on 30-12-2015 at 15:33
P-Nitrophenol


I am going to perform the synthesis of P-Nitrophenol using a procedure largely based on the synthesis of P-Nitroaniline. I am wondering whether or not the following reaction scheme would work:


Acetophenone.svg.png - 25kB

First is the nitration of the acetophenone which yields P and O nitroacetophenone. After isolation of the Ortho-product comes the acid hydrolysis of the nitroacetophenone,the acid is then neutralized with ammonium or sodium hydroxide.

[Edited on 30-12-2015 by Agari]




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NexusDNA
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[*] posted on 30-12-2015 at 15:47


Hi. You usually need peroxides or other strong oxidizers to cleave benzaldehydes and acetophenones to the phenols.

Where did you get this idea from?




Bromine, definitely bromine.
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Agari
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[*] posted on 30-12-2015 at 15:59


Quote: Originally posted by NexusDNA  
Hi. You usually need peroxides or other strong oxidizers to cleave benzaldehydes and acetophenones to the phenols.

Where did you get this idea from?

I got the idea from the reaction scheme for the synthesis of P-nitroaniline from acetanilide



nitroaniline.jpg - 28kB

[Edited on 31-12-2015 by Agari]




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[*] posted on 30-12-2015 at 16:09


That's the hydrolysis of an N-acetylamine, wildly different than the cleavage of a ketone. I would recommend preparing p-nitroaniline, then diazotizing that to form the phenol (see Org Syn for details)



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[*] posted on 30-12-2015 at 16:20


Oh ok. In the case of acetanilide it works because its the hydrolysis of an amide. You cant "hydrolyse" an acetophenone with just that, it would have very high energy carbocation intermediates (wont happen). Search about this.

What you want for your synthesis is oxidative cleavage.




Bromine, definitely bromine.
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Agari
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[*] posted on 30-12-2015 at 16:27


Quote: Originally posted by gdflp  
That's the hydrolysis of an N-acetylamine, wildly different than the cleavage of a ketone. I would recommend preparing p-nitroaniline, then diazotizing that to form the phenol (see Org Syn for details)


Can you please provide a link to the specific article of interest?




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[*] posted on 30-12-2015 at 16:31


Here's an example for a different regioisomer.



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[*] posted on 31-12-2015 at 00:39


Quote: Originally posted by Agari  

First is the nitration of the acetophenone which yields P and O nitroacetophenone. After isolation of the Ortho-product comes the acid hydrolysis of the nitroacetophenone,the acid is then neutralized with ammonium or sodium hydroxide.

you won't get significant ortho/para isomers if you nitrate acetophenone,you will get majority as meta
why don't you make p-nitrophenol from phenol itself ? there are many methods on SM using nitrate salts,catalysts (clay),and the good old HNO2 followed by dilute HNO3 route .

[Edited on 31-12-2015 by CuReUS]
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