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Author: Subject: synthesis of p-nitro-benzaldehyde
stavisoxido
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[*] posted on 3-5-2017 at 11:28
synthesis of p-nitro-benzaldehyde


Hello everybody,
I`m trying to find a syntetic route for p-nitro-benzaldehyde.
I found an article about p-nitro-toluene becoming p-nitro-benzaldehyde, but the yield of the nitration of toluene in the para position is very low, about 3%. I can work with that, but will be a lot of waste in this route. Any of you guys can help me with that?
Maybe a better synthetic route for p-nitro-toluene...
Thanks :D

[Edited on 3-5-2017 by stavisoxido]
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Boffis
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[*] posted on 3-5-2017 at 13:11


The yield of p-nitrotoluene from the nitration of toluene is about 30-35%, the problem is separating this isomer from the 60% or so o-isomer and the various other minor products. There are several methods of oxidation then to the appropriate aldehyde; chromates in acetic acid/acetic anhydride; condensation with alkyl nitrite/ alkoxides: convert to p-nitrobenyl bromide and then convert to aldehyde with hexamine or similar route etc. If you are interested I can dig out some refs. I thing I have a summary of methods/review for just this reaction somewhere.
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Melgar
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[*] posted on 3-5-2017 at 14:23


Nitrotoluenes are typically 2, 4, (2,4), or (2,4,6), since alkyl groups are typically ortho/para directing. So that 3% number is probably either wrong, or a misinterpretation.
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CuReUS
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[*] posted on 4-5-2017 at 03:27


Quote: Originally posted by stavisoxido  

I found an article about p-nitro-toluene becoming p-nitro-benzaldehyde

could you post the link to that article please ?
Quote:
Maybe a better synthetic route for p-nitro-toluene

http://www.tandfonline.com/doi/full/10.1081/SCC-100103545

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DrMethyl
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[*] posted on 4-5-2017 at 07:28


I suggest you :

Starting from benzyl alcohol then nitration to make the ortho and para isomers. Then oxydation to nitrobenzaldehyde with MnO2 or simply hypochlorite with catalyst.

Then distill the mixture to separate the isomers.
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chemplayer...
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[*] posted on 5-5-2017 at 01:27


My experience is that benzyl alcohol + nitric acid at any reasonable concentration generates benzaldehyde and benzoic acid as a result of oxidation. Vanillin you can nitrate extremely easily as it's a phenol, but not sure about benzyl alcohol - I suspect that the concentration of acid you need to nitrate will perform the oxidation quite readily.



Watch some vintage ChemPlayer: https://www.bitchute.com/channel/chemplayer/
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Booze
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[*] posted on 6-5-2017 at 10:35


Nah, make TATP instead.
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