# Theoretical p-Phenylenediamine synthesis

I am thinking on an alternative synthesis of pPDA, in which I need counsel. I was thinking about these easy reactions, and I want to ask if it can be done, or maybe you can hint me some reference. I am trough the reading of nitration and reduction of aniline, or from 4-nitrochlorobenzene or the DuPont synthesis.

The first route smells a bit fishy, but I think with enough heat, and molar ratios it can be done.

The second reaction is more promising for me since it is made from economic reagents, I'm fairly sure the ascorbic acid reduces the imine to the amine form. The only problem that could occur is with the reaction of 1,4-benzoquinone with ammonia. Can you validate my thoughts? I see no reason why it should not work.

Please if you have any suggestions or help, I gladly welcome it.

EDIT 1:

The comment from Waylander in wich he/she states the step from 1,4-benzoquinone to the imine form is probably not achievable. Howered i found also an another route from benzoquinone, wich is to react it with hydroxil-amine forming the oxime. *1 Then the question left behind is the step from oxime to amine, maybe the ascorbic acid still can do the job, however i dont find any source for it, but my assumption is that it still works.

• For the top route - I don't think it is a runner. Firstly treatment of phenols with PCl3 does not result in chlorobenzenes, it gives triphenylphosphites. Secondly treating chlorobenzene with ammonia, if one NH2 group goes in, it makes the ring more electron rich and less likely to undergo SNAr. I can find no reports of the bottom route though I do not have full database acces. Since it is a fairly obvious transformation I can only conclude that it does not work. – Waylander Jul 16 '19 at 16:01

I'd say the suggested reaction of benzene-1,4-diol (hydroquinone) with $$\ce{PCl3}$$ to get 1,4-dichlorobenzene would not work (see Waylander's comment). However, you can buy 1,4-dichlorobenzene very cheap (e.g., USD 21.50 for $$\pu{100 g}$$ bottle from Sigma-Aldrich) so why you need this trouble?
The suggested reaction of 1,4-dichlorobenzene with $$\ce{NH3}$$ to get benzene-1,4-diamine (p-phenylenediamine) would work, however, because there is a literature evidence for that (Ref.1). To do so, you need to use copper(I) chloride catalyst ($$\ce{CuCl}$$) and use 28% $$\ce{NH4OH}$$ solution as $$\ce{NH3}$$ source. Also need to heat the reaction mixture above $$\pu{200 ^\circ C}$$ in a pressure bomb (you may need to read this reference carefully before you start the reaction).