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gluon47
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n-propanol to propionaldehyde
I am trying to synthesize propionaldehyde from n-propanol. According to this site http://www.chemguide.co.uk/organicprops/alcohols/oxidation.h... primary alcohols can be partially oxidized to their corresponding aldehydes using
potassium dichromate (or any other suitable oxidizer).
I have a few questions:
1 would this procedure work to oxidize n-propanol since n-propanol is a primary alcohol?
2 unfortunately I don't have access to potassium dichromate so what oxidizer could I use instead? Wikipedia list a few https://en.m.wikipedia.org/wiki/Alcohol_oxidation
They all seem quite exotic and hard to obtain.
Would potassium permanganate work? if not what are a few other suitable oxidizers?
I am sorry if these are stupid questions
thanks in advance
[Edited on 21-9-2015 by gluon47]
[Edited on 21-9-2015 by gluon47]
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byko3y
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Oxidation of alcohol to aldehyde is one of extensively studied reactions, and it can be really tricky because a lot of oxidation agents will
overoxidize alcohol to carboxylic acid. Both permanganate and dichromate can be used, but you need a special procedure to obtain aldehyde and not
acid. It's either distillation, or pyridine complex, or quaternary ammonium complex, or simple phase separation, and many many more.
DMSO based http://www.sciencemadness.org/talk/viewthread.php?tid=13356&... :
Swern - oxalyl chloride + Et3N - -78 C
Pfitzner-Moffatt - DCC
Corey–Kim - Me2S + N-Cl-S + Et3N
Parikh–Doering - SO3*py + DMSO + Et3N
Albright-Goldman - DMSO + Ac2O ( + Et3N ? )
Albright-Onodera - DMSO + P2O5 + Et3N
Omura-Sharma-Swern - DMSO + TFAAA + Et3N
----
AgCO3/Celite (Fetizon's reagent);
TEMPO mediated NaOCl with Br- catalyst; using triphenylbismuth carbonate; Tetrapropylammonium perrhuthenate (TPAP); Dess-Martin reagent; IBX;
Al(iPrO)3 (Oppenauer conditions);
2-Iodoxybenzenesulfonic Acid as an Extremely Active Catalyst for the Selective Oxidation of Alcohols to Aldehydes, Ketones, Carboxylic Acids, and
Enones with Oxone
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gdflp
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Quote: Originally posted by byko3y  | Oxidation of alcohol to aldehyde is one of extensively studied reactions, and it can be really tricky because a lot of oxidation agents will
overoxidize alcohol to carboxylic acid. Both permanganate and dichromate can be used, but you need a special procedure to obtain aldehyde and not
acid. It's either distillation, or pyridine complex, or quaternary ammonium complex, or simple phase separation, and many many more.
DMSO based http://www.sciencemadness.org/talk/viewthread.php?tid=13356&... :
Swern - oxalyl chloride + Et3N - -78 C
Pfitzner-Moffatt - DCC
Corey–Kim - Me2S + N-Cl-S + Et3N
Parikh–Doering - SO3*py + DMSO + Et3N
Albright-Goldman - DMSO + Ac2O ( + Et3N ? )
Albright-Onodera - DMSO + P2O5 + Et3N
Omura-Sharma-Swern - DMSO + TFAAA + Et3N
----
AgCO3/Celite (Fetizon's reagent);
TEMPO mediated NaOCl with Br- catalyst; using triphenylbismuth carbonate; Tetrapropylammonium perrhuthenate (TPAP); Dess-Martin reagent; IBX;
Al(iPrO)3 (Oppenauer conditions);
2-Iodoxybenzenesulfonic Acid as an Extremely Active Catalyst for the Selective Oxidation of Alcohols to Aldehydes, Ketones, Carboxylic Acids, and
Enones with Oxone |
Do you have a reference for obtaining simple aldehydes with permanganate? I've never heard of that being used, only acidified dichromate. Also, if
the OP doesn't have access to potassium dichromate, somehow I don't think he has access to any of the other reagents you mentioned, such as
triethylamine, TEMPO, etc.
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byko3y
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Reagent availability strongly depends on place where you live. I can easily acqure dichromate and triethyl amine, but in no way can access
permanganate, while in US permanganate is easily available. Preparation of TEMPO derrivatives strongly depends on acetone accessibility.
Functionalization of crosslinked poly(4-vinylpyridine) and poly(4-vinylpyridine-co-styrene) with permanganate species: Preparation of
poly(4-vinylpyridinium permanganate)s and their use as oxidizing reagents
Heterogeneous kinetics of oxidation of alcohols: PTC techniques
An Efficient Selective Oxidation of Alcohols with Potassium Permanganate Adsorbed on Aluminum Silicate under Solvent-free Conditions and Shaking
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gluon47
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Thanks for your replies.
I have plenty of acetone. Do you think its worth synthesizing TEMPO for this experiment, e.g. Does it work well?
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byko3y
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It works great, if you need to oxidize a lot of alcohol, because you need to use a cheap oxidizer + catalyst.
Nobody tried 2-iodobenzenesulfonic acid, but I'm sure it has a good potential (japanese would not lie). Well, to behonest - I can't remember any
single report about TEMPO oxidation on this board. A lot of TEMPO preparations, yet no alcohol oxidations.
Aniline + sulfamic acid => Orthanilic acid
Orthanilic acid + NaNO2 ... + CuI => 2-iodo-benzenesulfonic acid.
[Edited on 21-9-2015 by byko3y]
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gluon47
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thanks think I'll go for TEMPO as I don't have any aniline.
found a thread of preparing triacetoneamine a precursor to TEMPO http://www.sciencemadness.org/talk/viewthread.php?tid=26985 seems fairly easy. ill try it this weekend
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gdflp
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There is a full synthetic writeup of TEMPO in Prepublications as well. See here.
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gluon47
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thanks a lot
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Texium
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Pyridinium chlorochromate is another option that I was thinking of making to selectively oxidize alcohols to aldehydes. You do need pyridine to make
it though that can be made from niacin as demonstrated by Magpie.
https://en.m.wikipedia.org/wiki/Pyridinium_chlorochromate
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gluon47
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seems like an interesting compound and relatively easy to synthesize to. pyridine looks doable as well but I think I'm a bit to scared to mess around
with hexavalent chromium so I think I'll stick with TEMPO but thanks anyway.
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gluon47
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just realised the triacetoneamine synth requires ammonium chloride so i added some 0.5M ammonia solution to some 10%ish hydrochloric acid. I noticed
white fumes of presumably ammonium chloride coming out of the reaction vessel. The mixture turned all milky. If i evaporate the mixture down am i
likely to obtain any solid ammonium chloride? or has it all escaped in the fumes?
I've done a bit of web surfing but i can't seem to find a clear answer.
any help would be appreciated 
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fluorescence
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Wasn't there something with Manganese Dioxide in Pyridine or am I mistaking ? I remember that using
freshly preprared Manganesedioxide from a Mn(II) and Mn(VII) Compound would react quite well to
the Aldehyde but not any further. But yeah that has been a while, I think it had something to do with Pyridine
but not sure. The problem is really common. We had an example where pH could be used, too and
the Aldehyde would form more likely at a specific pH but I'd have to look into my Organic Chemistry II - Script for that.
Edit:
Just found it. We had Chromic Acid as an Example where at a pH < 7 the Acid is formed and >7 the Aldehyde, but I am not sure whether the
Aldehyde branch used Chromic Acid, too. We just wrote [e-] there. But it would make sense. Many Redox-Reactions are dependent on the pH,
value. Many only happen in acidic condition, so elevating the pH Level would likely lower the reactivity a bit. But Aldehydes are very pH sensitive,
too. I read about a method how to get Aldehyde quite well without having too much Acid produced and discussed that with a friend some weeks ago. I
might have to check the Skype Chats for that.
Edit II:
Found that one, too. You can use destillation setup since the boiling point of your Aldehyde is much lower than the Alcohol it doesn't really matter
what Oxidant you are using. Even if it's a strong one as long as you destill the Aldehyde off it should work.
[Edited on 28-9-2015 by fluorescence]
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Waffles SS
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| Quote: |
Oxidation of Alcohols with Tetramethylammonium Fluorochromate in Acetic Acid
B. Sadeghy, Sh. GhammamiA
A number of alcohols were oxidized to the corresponding carbonyl compounds in excellent yields using tetramethylammonium fluorochromate in acetic
acid. The oxidant takes up two electrons, the reaction follows first-order kinetics with respect to the oxidant under pseudofirst-order conditions,
and the concentration of alcohols changes according to the Michaelis-Menten dependence.
http://link.springer.com/article/10.1007%2Fs11176-006-0008-0
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Tetramethylammonium fluorochromate(VI): a new and efficient oxidant for organic substrates
Ali Reza Mahjouba, , Shahriare Ghammamib, Mohammad Zaman Kassaeea
Tetramethylammonium fluorochromate(VI), (CH3)4N+CrO3F− (TMAFC), was prepared and used for quantitative oxidation of several organic substrates. This
new compound is more efficient and has certain advantages over similar oxidizing agents in terms of the amount of oxidant and solvent required, short
reaction times and high yields.
http://www.sciencedirect.com/science/article/pii/S0040403903...
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[Edited on 28-9-2015 by Waffles SS]
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Amos
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| Quote: Originally posted by fluorescence | Wasn't there something with Manganese Dioxide in Pyridine or am I mistaking ? I remember that using
freshly preprared Manganesedioxide from a Mn(II) and Mn(VII) Compound would react quite well to
the Aldehyde but not any further. But yeah that has been a while, I think it had something to do with Pyridine
but not sure. The problem is really common. We had an example where pH could be used, too and
the Aldehyde would form more likely at a specific pH but I'd have to look into my Organic Chemistry II - Script for that.
|
I've detected a very strong odor of acetaldehyde from a mixture of ethanol, manganese dioxide, and a small amount of sulfuric acid under reflux.
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fluorescence
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Manganese Dioxide is definately true, if it's made right before use it is strong enough to produce mostly Aldehydes.
But I can't find the solvent for that. I was very sure that it was Pyridine but I might be confused by the other Pyridine Oxidants here. That would be
something everyone can get and it would be quite weak and thus not produce too much
Acid. Problem is that not all Alcohols react with it.
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S.C. Wack
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I was going to suggest copper chromite but oh there's that Cr again. How about just the copper then
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zed
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Consult Vogel. Seems to me Vogel has some procedures for oxidizing alcohols to aldehydes.
Though Vogel's procedure might be the Org. Syn. procedure.
http://www.orgsyn.org/demo.aspx?prep=CV2P0541
The strategy is to slowly add oxidizer, and distill off propionaldehyde as it is formed.
Potassium DiChromate problems? Can't make it?
Plenty poisonous, but we never used to worry about it in the old days.
https://en.wikipedia.org/wiki/Potassium_dichromate
[Edited on 29-9-2015 by zed]
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gluon47
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Thanks heaps for your ideas everyone! Love this forum. I know there are a lot of other oxidizers witch you guys have mentioned but if i can get kMnO4
to work it'll make this project a lot simpler and easier (for me anyway) to perform with the resources avalable to me. dont know how i missed this
before. In this http://youtu.be/M8VSKqPYdHI video the guy oxidizese n-butanol to butyric acid this sugests that KMnO4 is capable of oxidizing primary alcohols so
in theory if i add KMnO4 to the propanol i could distill of the propionaldehyde before it got to overoxidized to propionic acid the boiling point of
n-propanol is 97 C and propionaldehyde is 46-50 C so the distilling flask containing the alcohol could be heated to 50 C before the addition of the
KMnO4
Does this sound viable?
[Edited on 29-9-2015 by gluon47]
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gdflp
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Possibly, it depends on whether the aldehyde is a major intermediate, or if the oxidation proceeds directly to the acid. It's worth a try on a small
scale to see if a worthwhile yield is obtained. It's possible that the alcohol will just be overoxidized to the acid.
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Boffis
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@byko3y where did you get this reaction from and do you have a reference?-
Aniline + sulfamic acid => Orthanilic acid
I know its a bit off topic but I am insanely curious.
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byko3y
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Boffis, Synthesis of Orthanilic Acid by the Reaction of Aniline with Sulfamic Acid
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Boffis
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Thanks byko3y
I had already found this paper but when you click on the link it is in Japanese. Tricky
There is just about enough data available in the abstract to make it worth a few experiments tough.
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zed
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posted on 29-9-2015 at 15:37 Reply With Quote Report Post to Administrator
"Thanks heaps for your ideas everyone! Love this forum. I know there are a lot of other oxidizers witch you guys have mentioned but if i can get kMnO4
to work it'll make this project a lot simpler and easier (for me anyway) to perform with the resources avalable to me.
Quote: Originally posted by gdflp
Quote: Originally posted by byko3y
Both permanganate and dichromate can be used
Do you have a reference for obtaining simple aldehydes with permanganate?
dont know how i missed this before. In this http://youtu.be/M8VSKqPYdHI video the guy oxidizese n-butanol to butyric acid this sugests that KMnO4 is capable of oxidizing primary alcohols so
in theory if i add KMnO4 to the propanol i could distill of the propionaldehyde before it got to overoxidized to propionic acid the boiling point of
n-propanol is 97 C and propionaldehyde is 46-50 C so the distilling flask containing the alcohol could be heated to 50 C before the addition of the
KMnO4
Does this sound viable?"
Dunno. I initially thought you had the sequence reversed. I was wrong.
But, the Organic Synthesis procedure does utilize refluxing propanol. To the extent it is possible, I would try to duplicate their reaction
conditions. As I recall, they add the oxidant dropwise, with vigerous stirring to the refluxing propanol. And, the glassware is set up to return the
higher boiling unreacted propanol to the reaction mix, while allowing the propanal to pass on and be collected by a very cold condensor.
The idea is to instantly remove propanal from the reaction mixture, as it is formed. About a 50% yield. If you veer from their procedure, expect
worse results.
Repeat. Refluxing propanol.
[Edited on 30-9-2015 by zed]
[Edited on 30-9-2015 by zed]
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gluon47
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Ok I'll give it a try with the propanol refluxing. Have to wait for my propanol to arrive first
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