H3O+
nitroacetanilides --------->nitroaniline---------->phenylenediamine
heatBlind Angel - 4-11-2006 at 12:36
I'm not a professional on the subject, but won't it be hard to separate the different isomers, i'm not sure that the ortho one will be produced in
majority (having nitrophenol and the like in head at the moment)Sergei_Eisenstein - 4-11-2006 at 16:37
Nitration of acetanilide will give a mixture of ortho and para-nitroacetanilide. Perhaps it may give one isomere in a much higher relative amount then
the other, but I wouldn't trust on it without backup from the published literature. If you can obtain o-nitroaniline, solo's procedure obviously is a
viable option, though it's not straightforward to nitrate acetanilide exclusively in the ortho position. You may be able to nitrate aniline in the
ortho position via the sulfonated intermediate.
Sometimes, these regioisomers are surprisingly easy to separate, but unless you can find a scientific paper that describes how to do it, it can be
tedious to accomplish for the kitchen chemist. I proposed 2-aminobenzamide (or its N-acyl derivative) because a Hoffmann rearrangement (can be
accomplished with NaOCl or NaOBr) would leave little doubt about the position of the two anilinic amines relative to eachother: they can only be in
ortho. Here is an example:
Try to see the beauty of this most simple and extremely valuable transformation. The carboxyl can be regarded as a synthon for an amine, which can be
diazotized and transformed in a wide variety of substituents. And you can do many of these reactions in your kitchen as well.ramarao - 4-11-2006 at 20:23
This is the general procedure adopted---------
Take ortho nitro chlorobenzene,convert it to ortho nitro aniline by reaction with ammonia solution at around 10kg/cm2 pressure.
Then ortho nitro aniline is hydrogenated using Raney -nickle catalyst at around 6 Kgs/cm2 pressure to get crude Ortho phenylene diamine.It is
purified by distillation.
However, in the lab if you do not have hydrogenation facility,one can do the reduction using Iron-acid.myinformation - 5-11-2006 at 07:47
there are many reference for o-phenylenediamine is here
1. SCHAEFER H.; GEWALD K.
Z. CHEM. <ZECE-AL>, 1976, 16, NO 7, 272
2. SCHAEFER W.; FALKNER C.
J. LIEBIGS ANN. CHEM. <JLAC-BF>, 1976, NO 10, 1809-1819benzylchloride1 - 19-12-2008 at 20:01
I am trying to produce O-phenylenediamine. I attempted a Hoffman rearrangement of phthalic acid diamide, but the procedure failed. I plan on trying it
again someday, altering the reaction conditions. I have produced anthranillic acid from phthalimide using the Hoffman reaction, but the yeilds were
low and the products was highly colored. At least Phthalic anhydride is cheap. I am currently trying to produce O-phenylenediamine from aniline. I
have plenty of aniline sulfate. I plan on turning this to sulfanillic acid by heating at around 150 C with concentrated sulfuric acid. Taking
advantage of the directing effect of the sulfonic acid group, a nitro group can be inserted ortho to the amine group. The sulfonic acid group can then
be removed by boiling with 60% sulfuric acid, producing O-nitroaniline. From O-nitroaniline, phenylenediamine can be easily produced. Has anyone
attempted the nitration of sulfanillic acid? I have nitrated many different compounds, but I am afraid to waste any of my sulfanillic acid with a
procedure that may not work. From reading this is the industrial way of producing O-nitroaniline. I would like to carry the reaction out on a 20-30
gram scale.stoichiometric_steve - 19-12-2008 at 23:50
Quote:
Originally posted by benzylchloride1
I attempted a Hoffman rearrangement of phthalic acid diamide
Was this supposed to work anyways? This is aliphatic chemistry, not aromatic...Sauron - 20-12-2008 at 01:43
This is very classical.
You start with acetanilid
Block the 4-position with a sulfonyl group
Nitrate exclusively to 2-position (avoid dinitration to 2,6)
Remove the sulfonyl group
Now you can reduce.
Two things to bear in mind:
1. o-phenylenediamine is easily oxidized
2. o-nitroaniline ischeaply available commercially.
The sulfonation and nitration steps are in Org Syn.
Thanks, grind, for correction.
[Edited on 20-12-2008 by Sauron]grind - 20-12-2008 at 03:38
Quote:
Originally posted by Sauron
Now you can oxidize.
Two things to bear in mind:
1. o-phenylenediamine is easily over-oxidized
Why oxidize? Do you mean reduce?solo - 20-12-2008 at 04:30
Reference Information
o-Phenylenediamine from sulfur, ammonia, and cyclohexane F. J. Weigert J. Org. Chem. 1981, 46 (9), pp 1936–1937
Excerpt
.......The ortho selectivity has precedent in reactions of sulfur
and amines with substituted organic compounds under
milder conditions.
Originally posted by benzylchloride1
I attempted a Hoffman rearrangement of phthalic acid diamide
Was this supposed to work anyways? This is aliphatic chemistry, not aromatic...
What is wrong with the Hoffman rearrangement on an aromatic compound? Especially one so deactivated for electrophilic substitution?Maja - 21-12-2008 at 04:47
What are you guys going to do with o-Phenylenediamine ?solo - 21-12-2008 at 07:11
..........does it matter?....., the purpose is irrelevant to the task at hand....save that inquiry for the censor's and want to be boy
scouts.......soloMaja - 21-12-2008 at 08:36
Not really. I'm just curious... Because I didn't knew any uses for it. solo - 21-12-2008 at 09:59
...then read this to be informed....solo
"...OPD -o-phenylenediamine is a chemical intermediate used in the synthesis of fungicides, corrosion inhibitors, pigments and pharmaceuticals. OPD is
also used to remove elemental sulfur in mining ores, and to remove aldehyde color formers in polymeric products."
It also is an excellent ligand for coordination chemistry, forming exceptional oxidation state metal complexes, lots of various colored complexes,
etc.. as common as ethylendiamine.benzylchloride1 - 22-12-2008 at 09:56
O-phenylenediamine can also be used to synthesize 1,10-phenanthroline, a useful ligand in coordination chemistry that costs over $20 a gram. Also it
can be used to synthesize various heterocycles. The reason that my Hoffman rearrangement reaction failed was that I dissolved the amide in a NaOH
solution which hydrolyzed the amide bond. I followed a procedure in Systematic Organic Chemistry by Cumming, Hopper and Wheeler. This book should be
taken with a grain of salt, II have a hard copy and I have read through the entire book, many of the percentage yields cannot be obtained by the
reactions in this book. I adapted the procedure from the anthranillic acid synthesis on page 291. I also ran this synthesis with phthalimide and
obtained a low yeild of anthranillic acid, 13g. The procedure would probably work better if the NaOH solution was first added to the NaOCl solution,
cooled and the amide added. The neutralization is extremely critical, since anthranillic acid is a highly soluble amino acid which only precipitates
in quantity at its isoelectric point. Back to O-phenylenediamine, I eventually will repeat this reaction, adding thes modifications: The NaOH solution
is first added to the NaOCl, then the amide is added. After the reaction is finished, the next problem is the isolation of the product. I would guess
that the O-phenylene diamine is fairly soluble in water. Repeated extraction with toluene may work, at least I have a rotary evaporator, which would
make the concentration of the solution fairly easy. I can buy O-nitroaniline and plan to do so. I would like to find a method of producing this useful
chemical cheaply with commonly available chemicals, so others who do not have access to commercial sources could be able to synthesize this useful
chemical.manimal - 8-5-2010 at 19:39
What would be the predominant isomer in nitrating diacetyl-o-phenylenediamine with mixed acid?
