CARBOXYLIC ACIDS FROM THE OXIDATION OF TERMINAL ALKENES BY PERMANGANATE. http://www.orgsyn.org/orgsyn/prep.asp?prep=cv7p0397 will work for Phenyl Ethyl Alcohol.

I can't believe I am typing this, but...

I don't agree, Wiz. Your highness, with the greatest respect, wouldn't the acidic conditions make the KMnO4 even more prone to cleaving the side chain, not less? No sarcasm, seriously, you have advanced the art.

We collectively haven't gotten to the bottom of this issue, but it is there. I know saying I can't find my reference is like saying I read it on a rest stop stall while glory holeing, but, there is something about the phenyl and KMnO4. I am ignorant and not the greatest chemist, but this doesn't work.

KMnO4 is the go-to oxidizer for primary alcohols to carboxylic acids. 2-phenylethanol and phenylacetic acid are both important chemicals to the flavoring/fragrance industries. If KMnO4 works than it should be an easy thing to search with the few different common names and find the refs using exactly these reactants. Anyone with library time to kill care to advance the art and prove me wrong?

While there why not grab us the refs of what does work. I have money on the addition of phenylethanol to refluxing sodium dichromate/sulfuric being 70-80% to PAA.

I'm not saying don't try it, just I'm not going to. I'm pretty sure other easy to source PTC's should work fine as well. Please let us know if it runs, but my money is against it. I really think KMnO4 is a dead end for phenylethanol, unless you are looking for benzoic acid.

Oxidation of primary alcohols to carboxylic acids. http://en.wikipedia.org/wiki/Oxidation_of_primary_alcohols_to_carboxylic_acids

http://www.chemguide.co.uk/organicprops/alcohols/oxidation.html

Download Oxidation of Primary Alcohols to Carboxylic Acids. http://rapidshare.com/files/42475815/Oxidation.of.Primary.Alcohols.to.Carboxylic.Acids.rar

@Goldmember,
"Ive not seen or found and easy otc oxidation of the alcohol"

DEVELOPMENT OF GREEN AND OF POLYMER-SUPPORTED
OXIDIZING AGENTS FOR OXIDATION OF ALCOHOLS
Gives a good overview at the start.
http://etd.lib.ttu.edu/theses/available/etd-04212006-170853/unrestricted/SyedJavedAliThesis.pdf

"On a side note, Phenylacetaldehyde.
I know I keep pumping this one,but how about"

Personally I think the TCCA is hard to get (I may be wrong), but otherwise seems sound.


Solvent free permanganate oxidations
Ahmad Shaabani and Donald G. Lee
Tetrahedron Letters 42 (2001) 5833–5836

Abstract—The oxidations of organic compounds by permanganate under solvent free conditions have been studied. Thiols and
primary aromatic amines undergo oxidative coupling reactions to give disulfides and diazenes, respectively, sulfides are oxidized
to sulfones, primary and secondary alcohols are converted to aldehydes and ketones, 1,4-diols and cyclic ethers give lactones and
arenes are oxidized to the corresponding a-ketones. The experimental procedure is simple and the products are easily isolated in
good yields.

http://www.erowid.org/archive/rhodium/pdf/solventfree.kmno4.oxidation.pdf


Mild and Efficient Oxidation of Aromatic Alcohols and Other Substrates Using NiO2/CH3COOH System
E-Journal of Chemistry
Vol. 5, No.2, pp. 365-369, April 2008
Abstract-A variety of aromatic alcohols were efficiently oxidized to their
corresponding aldehydes and ketones in good to excellent yields using nickel
peroxide activated by acetic acid. Some thiols and amines were also readily
oxidized by this oxidant under mild conditions."

http://www.e-journals.in/open/vol5/no2/0651-365-369.pdf

And two completely unrelated easter eggs;

Microwave- and Ultrasound-Accelerated Green Oxidation of Alcohols by Potassium Permanganate absorbed on Copper(II) Sulfate Pentahydrate
Synthetic Communications1, 38: 2011–2024, 2008
Copyright # Taylor & Francis Group, LLC
ISSN: 0039-7911 print/1532-2432 online
DOI: 10.1080/00397910801997819
Abstract-The solvent-free potassium permanganate (KMnO4)–promoted oxidation
of alcohols into the corresponding carbonyl derivatives has been examined
in detail with respect to the importance of supporting materials and supporting
irradiation. Secondary alcohols are oxidized very efficiently to the corresponding
ketones at ambient temperature by KMnO4 absorbed on a fourfold molar
amount of copper(II) sulfate pentahydrate. The reaction is accelerated considerably
by ultrasonic irradiation and drastically by microwave irradiation. Under the
latter conditions, also hydroquinone can be converted 100% into p-benzoquinone
within 4.5 min. Benzylic alcohols are oxidized most efficiently to the corresponding
benzaldehydes under heterogeneous reaction conditions."

http://www.hoahocxanh.com.vn/data/upload_file/File/tap%20chi%20nhom%202008/SC2008-38-2011.pdf

Fast and Green Microwave-Assisted Conversion of Essential Oil Allylbenzenes into the Corresponding Aldehydes via Alkene Isomerization and Subsequent Potassium Permanganate Promoted Oxidative Alkene Group Cleavage
Molecules 2009, 14, 3411-3424; doi:10.3390/molecules14093411

Abstract-Essential oil allylbenzenes from have been converted quickly and efficiently
into the corresponding benzaldehydes in good yields by a two-step “green” reaction
pathway based on a solventless alkene group isomerization by KF/Al2O3 to form the
corresponding 1-arylpropene and a subsequent solventless oxidation of the latter to the
corresponding benzaldehyde by KMnO4/CuSO4????5H2O. The assistance by microwave
irradiation results in very short reaction times (<15 minutes). The green conversion of
eugenol (4-allyl-2-methoxyphenol) into vanillin (4-hydroxy-3-methoxybenzaldehyde) has
been carried out in a similar way, requiring however two additional microwave-assisted
synthetic steps for acetylation of the hydroxy group prior to the oxidation reaction, and for
the final deacetylation of vanillin acetate (4-acetoxy-3-methoxybenzaldehyde) by
KF/Al2O3 under solvent-free conditions, respectively.

http://www.mdpi.com/1420-3049/14/9/3411/pdf

Please do not think the above paper strengthens the case for cleavage to the corresponding benzoic acid, because the above is for alkyl arene's. And alkyl arenes ARE cleaved by permanganate which results in the corresponding benzoic acid, whereas primary and secondary alcohols are oxidized to an aldehyde then a carboxylic acid.

Oxidation Brochure
http://www.acros.com/_Rainbow/pdf/oxidation_brochure_MANGA.pdf

"However, there are a number of drawbacks against the classical oxidants (CrO4 2-, MnO4-) and their use in organic synthesis. These include lack of selectivity, the requirement of a strong acid or base as catalyst and above all their high toxicity for man and environment"

When they said that, they were referring to the ability (or inability) of permanganate for example to go to the aldehyde and stop before then going to the carboxylic acid. And those particular researchers were angling for the aldehyde, so in their case the inability of stronger permanganate to stop half way at the aldehyde was a drawback. But if you were going for the carboxylic acid permanganate would actually be preferred.

"I guess they couldn't find a better way to make chlorine gas. Oh well, they somewhat avoided the use of KMnO4, even though I thought it wasn't so bad."

You know that first part of the procedure (ie, 'A solution of KOH (22.4 g) in 100 mL of water was chilled and chlorine gas (generated from 20 g of KMnO4 and 120 mL of concentrated HCl) was slowly bubbled over for one hour period with stirring.") Is just a fancy way of producing hypochlorite, you could easily miss that whole section involving chlorine gas and just add hypochlorite (bleach) from the start!

Also good luck with your further endeavours! I would love to have a look at any references you could find for the procedure you did above, I may have a dig around for you if I get the chance. If you need anything dont hesitate to ask us!

Selective benzylic -OH oxidation with KMnO4 to ketone is possible without benzylic cleaverage to benzoic acid.


http://www.orgsyn.org/orgsyn/pdfs/CV1P0241.pdf

Disposable Stirbar, lol good name. Last week I dumped a thick solution of powdery crap in solvent that was in a flask down the drain, then remembered later my little stirbar was in there! (DAMN, I guess that was an expensive Disposable stirbar).

If you want success, why dont you use the method from the microwave paper?

That would be;



You would want the second method, that uses the concentrated aqueous solution of permanganate to alumina, then ground with copper sulfate. They say the best results are given when a 20% copper sulfate and 80% alumina are added to an equal weight of permanganate. So that works out to Potassium Permanganate = 50%, Copper Sulfate pentahydrate = 10% and Alumina = 40%. The reaction should take about 8 hours(?) at room temperature without microwave irradiation. As you can see they simply add the oxidant (Permanganate, Copper sulfate and alumina) to a flask followed by the alcohol (reductant). TLC analysis would be great to monitor the reactions progress and to be able to determine when it has completed. This is of course for a near quantative yield of the corresponding aldehyde, you could bypass the alumina and receive a mixture of the aldehyde and the corresponding carboxylic acid. But it is easier to work up one product in good purity than two, then you also have just one product to work with (buy reagents for ect). Alumina can be had at pet shops that sell aquarium supplies 'Phos Zorb' is one such product that consists of a pouch full of activated alumina and nothing else.

Ref;
Solvent free permanganate oxidations
http://www.erowid.org/archive/rhodium/pdf/solventfree.kmno4.oxidation.pdf

Also make sure you have 2-Phenylethanol, as 1-phenylethanol can only produce acetophenone.

Naf1,
I really couldn't count how many stirbars I have tossed. It is an expensive and stupid habit.
A more expensive habit... I turned a 5L 3 neck with a mechanical stirrer in it so I could inspect the propeller from the bottom and tapped the arbol on the wall, putting a couple hundred dollars of fancy glass right through the bottom of a much more expensive piece of glass with a weak little "tink". Not even a mighty smashing of glass that would let me really experience the destruction.
I guess I have been thinking about the microwave too much these days and it mentions them right in the second paragraph. That, and I read the (r) for just oxidizer and alumina from the example above #17. One could guess that the time would be similar but without running spots you would be going it blind.
This doesn't fix the reason I am not going to try it. I am interested in different routes to PAA. I know I/we sort of took over the thread, but other peeps here want the aldehyde, not me if it is going to take a day to get to a point that I have to do another reaction to get what could be had from one reaction. I don't kid myself anymore when I read the time it takes. If it really only needed to react for 4hrs, and that is a big if, throw setup, dicking around, finally getting to work, reaction time, more dicking around, work up, distilation... yeah, lucky if it only took a day.

Sedit,
Although I think rdx is a better use of nitric, I might even get around to this one. As soon as I want PAA again it might get a go depending on what I have on hand and how I feel about the other contending trials and if I want to try my hand at huffing nitrogen oxides.
http://www.orgsyn.org/orgsyn/orgsyn/prepContent.asp?prep=cv1p0018
Got a link to anything with a better yield?

An extra helping of the oxidant, KMnO4 mix, and more time in the microwave would then probably push us past the carboxylic acid to oxidative cleavage by the time there was no more aldehyde and that was the original problem I and Goldmember stated with KMnO4. How much? Who knows without trying. But the others do look promising. I will report on future endeavors, be that success or failures.

I have learned tons from reading about the ways others have failed and their thoughts about it. I feel it is as important as the success stories and really helps others not to repeat hard learned lessons.

Got any ozone with something added for selectivity possibilities? I had a dream of a hot tub filled with phenyl ethanol and metal salt or something with the pumps and ozonator going. Is this even possible? Google time.

"Most reactions can be carried out at room temperature; however, improved yields for solid reductants are obtained when the reaction
temperature is near or above their melting points. Some reactions benefit from the application of additional energy in the form of microwaves."

Sure, doesn't "need", and probably not wise to start off modifying the ref on the first try, but then again, I'm not wise.

I also love nuking stuff.

Hello to all,

@ Locked
Can you write-up the exact procedure that you follow (Na2Cr2O7 + H2SO4 oxidation)
That will be nice 


So my first and useless post,
at your nice and more "advanced" Chemistry related forum.