I am basically using a mixture of iron and hydrochloride to reduce an aromatic nitro group into an amine, but the problem is that the iron is still left in the reaction mixture. I have tried passing my reaction mixture through a celite pad, but with no success. I have also tried a basic aqueous workup of my sample, but still found no success. Kindly suggest appropriate methods to solve this problem.
EDTA on polymer like http://www.dow.com/versene/applications/polymerization.htm to bind iron salts, magnet or acid excess for fine metallic iron
Joshi,
This is a well known procedure and its work up is
"The reaction mixture is filtered to remove the iron residue which is washed with ethyl acetate [or other solvet] (... mL). The filtrate is partitioned with 2M KOH and the basic layer is further extracted with ethyl acetate [or other solvent] (3 x ... mL). The combined organic extracts are washed with brine (2 x ... mL) and water (3 x ... mL), dried (MgSO4) and concentrated under reduced pressure. The crude residue is then subjected to flash silica gel column chromatography"
at the end you will have pure organic product (iron free).
Good luck
If possible, try to implement another method for reducing -NO2 to -NH2. The Fe/HCl or Sn/HCl classic methods are not that efficient. Please see the alternative in this paper:
H. Aliyan, R. Fazaeli *, H. Javaherian Naghash, A. R. Massah, and F. Saliminejad,
A Chemoselective and Green Reduction of Nitro Arenes to Aromatic Amines with FeSO4, NaBH4, H3PW12O40 in Water at Room Temperature, Journal of Nanostructures, 1, 21-26, (2012)
If your aromatic amine is in an oily phase, just extract it from the reaction mixture after neutralization of excessive HCl.
It is also possible to convert amine into its HCl salt by addition of HCL. In this case you should obtain homogenous solution of product with dispersed Fe. Filter off the mixture /centrifuge?/ and neutralize it to obtain emulsion or precipitated free amine base.
- Badges
- Science topic
- Similar topics
- Chemistry
- Organic Chemistry