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I am trying to synthesize P2NP for an experiment I'm documenting online, and I have a hard time.

17ml benzaldehyde were added to 35ml of (kind of anhydrous) ethanol, with 14ml nitroethane (the benzaldehyde was not distilled beforehand or washed with baking soda solution but was tested and had ph around 6, which meant no much benzoic acid contamination) and 4ml di-n-butylamine, and something like 2ml glacial acetic acid was added to reach neutral ph of 7.

No dean-stark trap was used, but it is said water would prevent good yield, which implies some yield at all.

This was boiled on reflux for about 3h and become dank orange. it was put off heat and cooled in the fridge. No crystals formed >:(. The solution still smelled like benzaldehyde, which makes me think the reaction is not complete.

So, what am I doing wrong?

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Distill your benzaldehyde then try using the ammonium acetate in acetic acid conditions. This has been detailed here: J. Org. Chem. 1953, 18 (1), 1–3. To quote:

The aldehyde (5g), 5 ml. of the nitroalkane, and 2g of ammonium acetate were added to 20 ml of glacial acetic acid. The resulting solution was refluxed for two hours and then poured into ice-water. If a solid product was obtained it was collected and recrystallized from methanol, ethanol, or acetic acid. If the product was an oil it was separated and crystallized, if possible, from one of the above solvents.

The authors record a 55% yield for the product you want.

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  • $\begingroup$ I have ammonium acetate but it is very wet. Is that going to be a problem? $\endgroup$ – Nigel Jul 5 '18 at 13:01
  • $\begingroup$ Probably not, try it. $\endgroup$ – Waylander Jul 5 '18 at 13:05
  • $\begingroup$ Ok, I will, thank you. Accepted your answer. Check my other question if you like: chemistry.stackexchange.com/questions/99120/… Thank you very much. $\endgroup$ – Nigel Jul 5 '18 at 13:16

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