photosyn
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synthesis of 2,3,5-trimethyl-4-aminophenol
Hi everyone -
I plan to synthesize some 2,3,5-trimethyl-4-aminophenol, which is cited as a photographic developer. This would be my first organic synthesis since
leaving university 35+ years ago, so I'm asking for some advice.
The basic plan is to follow the procedure described in this patent
https://patentimages.storage.googleapis.com/0f/14/e8/feae4ea... copied here for convenience:
I'm fairly sure the reference to sodium nitrate is a typo and should be sodium nitrite - is that correct?
Is it reasonable to conclude that I need basically just a flask, a heated stir plate, and a buchner funnel and a vacuum source for filtration?
Can anyone forsee any gotchas or difficulties with this? Thanks for any advice.
[Edited on 7-7-2024 by photosyn]
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bnull
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Welcome to the forum.
Yes, it is a typo. Nitrate, ha ha.
Quote: Originally posted by photosyn  | | Is it reasonable to conclude that I need basically just a flask, a heated stir plate, and a buchner funnel and a vacuum source for filtration?
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Two flasks but you're essentially right.
Quod scripsi, scripsi.
B. N. Ull
P.S.: Did you know that we have a Library?
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photosyn
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Thank you - very helpful to have some assistance.
When it says "the diazo slurry was then added" does that suggest the quantities given generate a precipitate of the diazonium chloride salt? I have a
concern, generated by this page ("Supersaturated Diazonium salt causes Fatality")
https://web.archive.org/web/20181006095115/http://www.crhf.o...
I found this more detailed description of essentially the same synthesis, on this page:
https://www.benchchem.com/product/b046268 - very close to equal molar quantities of sulfanilic acid, sodium nitrite and 2,3,5-TMP in both cases.
In which textbook might I find another verified recipe for creating a safe solution of the sulfanilic diazide?
[Edited on 8-7-2024 by photosyn]
[Edited on 8-7-2024 by photosyn]
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EF2000
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| Quote: Originally posted by photosyn | Thank you - very helpful to have some assistance.
When it says "the diazo slurry was then added" does that suggest the quantities given generate a precipitate of the diazonium chloride salt? I have a
concern, generated by this page ("Supersaturated Diazonium salt causes Fatality")
https://web.archive.org/web/20181006095115/http://www.crhf.o...
In which textbook might I find another verified recipe for creating a safe solution of the sulfanilic diazide?
[Edited on 8-7-2024 by photosyn]
[Edited on 8-7-2024 by photosyn] |
Not sulfanilic diazide, but rather p-benzenediazonium sulfonate.
I found two recipes: one lab manual from Truman University (Missouri) for synthesis of Orange II. First step is sulfanilic acid diazotization: https://chemlab.truman.edu/files/2015/07/Synthesis-of-Orange... (2nd page). It says that "white, powdery precipitate" forms.
And another from OrgSyn procedure: 1,2-AMINONAPHTHOL HYDROCHLORIDE. First step in second procedure. They say that "p-benzenediazonium sulfonate separates on stirring" and forms a
suspension. Note below says that solution of the diazoic acid is much less stable than suspension of the salt.
So it appears that suspension of diazonium sulfonate is more safe than diazoic acid solution. If the reaction is included in university lab manuals,
it should be safe enough for undergrads, right?
| Quote: Originally posted by photosyn |
Is it reasonable to conclude that I need basically just a flask, a heated stir plate, and a buchner funnel and a vacuum source for filtration?
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You will also need a bucket or other container with ice. Diazonium compounds are stable only at 0-5 °C.
[Edited on 8-7-2024 by EF2000]
Wroom wroom
"Head is a terrible thing to lose" - Tolle Koenig
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bnull
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From Vogel's Textbook of Practical Organic Chemistry (p. 591): | Quote: | | Solid diazonium salts are very sensitive to shock when perfectly dry and detonate violently upon gentle heating: they are, therefore, of little
value for preparative work. Happily, most of the useful reactions of diazonium compounds can be carried out with the readily-accessible aqueous
solutions, so that the solid (explosive) diazonium salts are rarely required. |
From Fieser's Experiments in Organic Chemistry, "Diazotization of Sulfanilic Acid" (p. 208): | Quote: | | The product is not collected but is used in the form of the suspension. It is more stable than most diazonium salts, and it will keep for a few hours,
but not indefinitely. |
@photosyn: You may want to take a look at Gattermann's Laboratory Methods of Organic Chemistry, "Aromatic Diazo-Compounds" (p. 281), Cheronis'
Semimicro and Macro Organic Chemistry, "Preparation of Diazonium Salts" (p. 271), and the two books above. We have copies in the Library.
| Quote: Originally posted by EF2000 | | If the reaction is included in univerity lab manuals, it should be safe enough for undergrads, right? |
Are you sure?
Quod scripsi, scripsi.
B. N. Ull
P.S.: Did you know that we have a Library?
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EF2000
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| Quote: Originally posted by bnull |
@photosyn: You may want to take a look at Gattermann's Laboratory Methods of Organic Chemistry, "Aromatic Diazo-Compounds" (p. 281), Cheronis'
Semimicro and Macro Organic Chemistry, "Preparation of Diazonium Salts" (p. 271), and the two books above. We have copies in the Library. |
Gatterman's, page 300 (link), synthesis of Helianthine (methyl orange) starts with diazotation of sulfanilic acid and apparently a solution is formed, not a suspension.
Wroom wroom
"Head is a terrible thing to lose" - Tolle Koenig
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bnull
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Strange. And it is even more concentrated than Fieser's. Supersaturated perhaps?
Quod scripsi, scripsi.
B. N. Ull
P.S.: Did you know that we have a Library?
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photosyn
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Thank you everyone, this is enormously helpful. I will report back with any progress.
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photosyn
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In the mean time, I read up on some more background information. The diazonium salt is also called Pauly's Reagent, used for testing for histidine and
tyrosine - https://microbenotes.com/paulys-test/
In the webpage I linked to above referring to a fatality caused by sudden decomposition of a diazonium chloride salt, it doesn't say which one.
When the OrgSyn website says the "solution of the diazoic acid is much less stable than suspension of the salt" perhaps it doesn't mean (un)stable in
quite the way I was afraid of, and perhaps I'm fussing about nothing.
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bnull
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| Quote: Originally posted by photosyn | | When the OrgSyn website says the "solution of the diazoic acid is much less stable than suspension of the salt" perhaps it doesn't mean (un)stable in
quite the way I was afraid of, and perhaps I'm fussing about nothing. |
Better safe than sorry.
Quod scripsi, scripsi.
B. N. Ull
P.S.: Did you know that we have a Library?
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Boffis
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The bigger problem as I see it is obtaining 2,3,5-trimethylphenol. Are you going to purchase it?
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