Chem Science
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Zinin Reaction on Nitrobenzene
Hello everyone !!
So a couple of years ago i wanted to make Aniline to use it in some reactions and synthesis projects, But i have troubles in the common methods, Fe
and HCl approach did not work for me, Tin HCl is to expensive (The tin) Tin Chloride more expensive ... But Sodium Sulfide is not that expensive and i
had Nitrobenzene that i bought some time ago. And i found the Zinin reaction. In sciencemadness there was a post (http://www.sciencemadness.org/talk/viewthread.php?tid=63564) but got no nothing ensencialy. So i did some research and try and here is what i got.
On a 1L RBF i place 100g of lab grade Sodium Sulfide (60% claim by analisis, however it was slightly brown and i didin's reclame these to the company)
200ml of water, 50ml of nitrobenzene and another 300ml of water to wash the Nitrobenzene from the beaker.I then put these to Reflux for 3hs. After
these i extracted aniline by steam distillation . 300ml of water was distilled, to these i add 60g of NaCl to salt-out the aniline, separate with
sepatory funnel, do an Acid Base wash (Some nitrobenzene came out here) steam distill again, salt.out, dry with Na2SO4 and distil aniline. Yield was
50% The best yield, is 60% in my case, with 10% excess sodium sulfide, i believe that whatever was contaminating my sodium sulfide impacted my
Yield.It was my first time i got something contaminated from a Lab supplier. So i didn't go and reclame or anything.
EXPERIMENTAL NOTE
Very good reflux is needed, and cool water, I have low yields because my water reservoir (didint had a big one at the time )het up to 30 C and i had a
short condenser. (Super amateur yea)
BAD NEWS
The aniline from these method is contaminated with sulfur compounds, and besides a couple of distillations it always turns deep red in a short time.
To remove Sulfur compunds you can reflux with Tin Chloride or Zinc metal. and then distill. but i didint try these
I do have nice yellow sodium sulfide, but i didn't try the synthesis. i believe that Yield might be better.
Okay see you Next time 
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Tdep
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Location: Laser broken since Feb 2020 lol
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Mood: PhD is done! It isn't good but it's over lol
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The method I want to see tried is the Mg/MeOH reduction. Mg is cheap, probably doesn't have to be of high quality, and there's no awful sulfur or iron
stains. I've attached a file about the reduction, its from elsewhere on SciMad, not sure anyone has tired anything on this though.
I always get a bit sceptical when I see these 'wonder' reagents that can do so much, I feel like people publish papers where they just bullshit their
way through results because 'it worked for aldehydes, it'll work for nitro groups!' and no-one questions them. But maybe it is good, i'm often wrong
Attachment: Mg-MeOH Reduction.pdf (208kB)
This file has been downloaded 1105 times
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Chem Science
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thank you very much for that I will give ir a try at some point that can be the
solution to my problems
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Chem Science
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Registered: 30-7-2018
Location: Argentina
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[Edited on 3-1-2019 by Chem Science]
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