Easy Oxidation of THF to GBL

[foxy2]

This is essentially the same of more work for GBL, however some of the other uses might bee of interest.

Use of ruthenium tetroxide as a multi-purpose oxidant.
Berkowitz, Lewis M.; Rylander, Paul N.   
J. Am. Chem. Soc.  (1958),  80  6682-4. 

Abstract: The scope of the oxidation reactions of RuO4 (I) was investigated.  I was prepd. by the slow addn. of N NaBrO3 to 4.37 g. RuCl3 (contg. 18% H2O) in 80 ml. refluxing 0.5N HCl, while I and H2O distd. into an ice-cooled receiver.  I (55% yield) was then decanted and dissolved in CCl4 to give a deep red soln.  Alcs. were oxidized rapidly by I to carbonyl compds.  Thus, I in CCl4 was added to 1.50 g. cyclohexanol in 10 ml. CCl4 at 10-15° (ice-cooling was required).  After standing overnight at room temp. the mixt. gave 2.18 g. RuO2 and 93% (based on I) cyclohexanone.  Similarly, the following compds. were prepd. from the corresponding alcs. in the indicated yields: l-menthone, 96%; 3-cholestanone, 49%; BzH, 90%.  n-C6H13OH, however, gave only 10% n-C5H11CO2H even with excess alc. trans-1,2-Cyclohexanediol in H2O gave 15% dione (or oxo-alc.).  Aldehydes were oxidized rapidly to acids to give 33% BzOH and 30% n-C6H13CO2H.  Olefins were oxidized to aldehydes with C-C bond cleavage,(hmm...piperonal from piperine or from isosafrole? in contrast to OsO4 which gave diols.  Thus, cyclohexene gave 10% adipaldehyde and 1-octene gave 12% n-C6H13CHO and (presumably) CH2O.  The low yields were possibly due to the difficulty in sepg. the products from RuO2.  Me cyclopropyl ketone reacted little, if at all, with I.  A unique reaction of I was the oxidation of ethers to esters.  Thus, 2.55 g. Bu2O and 1.91 g. I in CCl4 gave a quant. yield of PrCO2Bu,while tetrahydrofuran gave a nearly quant. yield of g-butyrolactone which could not be oxidized further.  An attempted oxidation of ethylene oxide at 0° in CCl4 to an a-lactone (II) gave only a polymer, possibly derived from II.  Tetrahydrofurfuryl alc. gave a compd., possibly an aldehyde lactone, forming a dinitrophenylhydrazone.  Although esters were stable to I, amides were oxidized to imides.  Thus, 1.33 g. g-butyrolactam and 1.69 g. I gave 49% succinimide.  N-Heptanoyl-n-hexylamine similarly gave an imide.  C6H6 and EtCHMePh gave immediate reactions with I to yield unidentified carbonyl compds.  C5H5N, (PhCH2)2, Ph3CH, tetrahydronaphthalene, 1-O2NC10H7, (PhN:)2, PhC.tplbond.CH, and (PhC.tplbond.)2 also gave immediate reactions but no isolated products.  Slower reactions of I with Am3N, Et2NH, and piperidine apparently gave amides, while n-C6H13NH2 apparently did not.  Ru is less volatile, less toxic, less expensive, and more readily available than Os. 
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[Osmium]

Os is confused.

Is it bromate as foxy2's ref says or Br2 according to Rhodium's article that oxidises the THF?

Prdy2GO: add H2O2 or another oxidiser anyway.

[Prdy2GO]

Thanks Os but this was one of the only times I actually through something out. I am not able to find my NaBROMATE so I know you were thinking of using something else and I would like to try something else as well what would you suggest? BTW was my procedure ok besides the wrong Na that is?
TTFN
Don't look at me I didn't do it!

[foxy2]

Tetrahedron Letters
Volume 42, Issue 34
(2001) Pages 5833-5836

Solvent free permanganate oxidations

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 -ketones. The experimental procedure is simple and the products are easily isolated in good yields.

Best results are obtained when KMnO4 is first mixed with copper sulfate pentahydrate (or a 20/80 mixture of copper sulfate pentahydrate and alumina) to give a reagent that has previously been used extensively as a heterogeneous oxidant in inert solvents. The reductant is then added dropwise while the solid oxidant is tumbled using a magnetic stirrer. 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.[8 and 9] Product isolation can be achieved by washing the spent oxidant with an organic solvent, which can subsequently be recovered by simple distillation. Many of the reactions are nearly quantitative giving products of relatively high purity.

Preparation
The oxidant is prepared by grinding equal amounts of potassium permanganate and copper sulfate pentahydrate in a mortar until homogeneous or by adding a concentrated aqueous solution of potassium permanganate to alumina, giving a paste which is then ground with an equal amount of copper sulfate pentahydrate. Reductant (2 mmol) is added to a portion of the oxidant (~4 g) in a 25 mL round bottomed flask and stirred magnetically until TLC analysis indicates a completed reaction. The residue is then washed with a minimum amount of solvent (methylene chloride, hexane and/or ether). Distillation of the solvent gives a product that is of acceptable purity for most purposes. If greater purity is required, the product can be distilled or recrystallized.

The following two procedures were performed at room temperature useing the oxidant KMnO4/Al2O3/CuSO4·5H2O.

1,4-butanediol for 14 hours yeilds 95% GBL

tetrahydrofuran for 6 hours yeilds 70% GBL
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[Osmium]

Well, I have a few grams of RuCl3 at home, but since it fell in my lap by divine inspiration I can't comment on its price right now, except that it is probably VERY expensive by most bee's standards. Sounds like it will work in catalytic amounts and bromate or other oxidisers can be used with it (I don't see any reason why it shouldn't work). But what solvent? Chlorinated hydrocarbons will not dissolve most oxidisers.

[foxy2]

Osmium
I would trust Rhodiums reference for the mechanism.  They are forming bromate which seems to bee equivalent to adding bromate, i would assume. 

Here is what they say in Rhodiums ref

The fact that the rate of oxidation accelerates during the
process, strengthens our assumption that oxidation with
bromine is the main operating mechanism. When bromine
oxidizes THF, bromide is formed. Bromate can react with
the bromide in the acidic medium to yield bromine.

If we assume that 2.5 molecules of Br2 react with THF according to Scheme 7 to yield five bromide ions, these
ions will then react with one molecule of bromate to
produce three molecules of bromine. Thus, in this cyclic
process in which we start with 2.5 and produce three
molecules, which can now further oxidize the ether, we
gain half a molecule of Br2. In each oxidative cycle we
produce an extra half a molecule of bromine and the result
is acceleration of the oxidation reaction. This is a typical
autocatalytic process.

We suggest the following general scheme (Scheme 9) to
describe the oxidation process of ethers with bromate
salts: a slow initiation process, in which Br2 is formed
followed by an accelerated propagation process.

In conclusion, our data on direct oxidation of ethers with
bromate point towards bromine as the main active oxidant.
Bromate itself is responsible only for the initiation step and than plays the role of a co-oxidizer or bromine supplier.

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[foxy2]

The yeilds are not stellar but.....

g-Butyrolactone from tetrahydrofuran.    
Hara, Hiroshi.  (Japan). 
Japanese Patent  JP  53087347  19780801

Abstract: THF (0.5 mol) and 0.1 mol FeSO4 in H2O was treated dropwise with 1.05 mol 30% H2O2 at (less than)30°C and the mixt. stirred 3 h at 30°C and 8 h at 45°C to give 61.6% g-butyrolactone. 
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[foxy2]

Novel oxidation of tetrahydrofuran to g-butyrolactone with peroxyphosphoric acid.    
Ogata, Yoshiro; Tomizawa, Kohtaro; Ikeda, Toshiyuki.
J. Org. Chem.  (1980),  45(7),  1320-2. 

Abstract: THF was oxidized with peroxyphosphoric acid (H3PO5) at 25° to give g-butyrolactone in 80-90% yield based on the decompd. H3PO4 neat or in MeCN.  Little effect of O and radical inhibitors on the yield suggests that this reaction proceeds via an ionic mechanism involving g-hydroxybutanal and a-hydroxytetrahydrofuran.  Similar oxidn. of Bu2O gives the corresponding ester in a moderate yield and that of tetrahydropyran gives a trace of the corresponding lactone. 


Preparation and estimation of peracids and peroxides.     Afzal, S. M.    Fac. Pharm.,    
Pak. J. Sci.  (1980),  32(3-4),  201-4.

Abstract: HOOSO2(OH) was prepd. by reaction of ClSO2(OH) with H2O2 in isoamyl alc., by reaction of K peroxydisulfate with BCl2, by boiling Ba peroxydisulfate in H2O, by anodic oxidn. of H2SO4, or by bubbling SO3 through H2O2 soln.  Peroxydisulfuric acid was prepd. by electrolysis of H2SO4, hydrolysis of K peroxydisulfate, or by reaction of ClSO2(OH) with H2O2.  HOOPO2(OH) was prepd. by reaction of P2O5 with H2O2 in MeCN.  Peroxydiphosphoric acid was prepd. by reaction of H4P2O7 with H2O2.

Novel decontamination agents. Destruction of organophosphorus and sulfur toxic agents by monoperoxyphosphoric acid.    
Lion, Claude; Hedayatullah, Mir; Pires, Fabrice; Charvy, Claude; Briand, Sylvette; Magnaud, Gilbert; Delmas, Gerard; Sentenac-Roumanou, Et Henri.  
Phosphorus, Sulfur Silicon Relat. Elem.  (1996),  118 89-94.
 
Abstract: H3PO5, monoperoxyphosphoric acid easily prepd. by the reaction of H2O2 with P2O5 in acetonitrile, is a very good decontamination agent.  The destruction of toxic S and P agents is completely achieved in very short time. 

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[Osmium]

Oh my!
Peroxyphosphoric acid works! Sounds like the beloved oxone is worth a try too!

We used to clean clogged fritted glass filters by pouring some THF into them, and adding fuming HNO3. Once the acid was in you better hurried and closed the fume hood because after a few seconds this mixture started giving off NOx fumes like crazy. Really makes me wonder what intermediate was formed in that reaction  

[Osmium]

> THF (0.5 mol) and 0.1 mol FeSO4 in H2O was treated
> dropwise with 1.05 mol 30% H2O2 at (less than)30°C and
> the mixt. stirred 3 h at 30°C and 8 h at 45°C to give
> 61.6% g-butyrolactone. 

Fe(2+)/H2O2 is a known radical starter for aq. medium. I don't know, makes me kinda nervous because of possible peroxide formation. I hope the other 40% of THF didn't turn into evil peroxides  


> Thanks Os but this was one of the only times I actually
> through something out. I am not able to find my NaBROMATE
> so I know you were thinking of using something else and I
> would like to try something else as well what would you
> suggest?

Repeat what you described up there using 103g NaBr instead of the 151g NaBrO3. Once this works we might be able to even reduce the amount of NaBr further. In case you don't have any KHSO4 you can simply use half the molar amount of H2SO4, or a little more than that. Then drip in 1mol H2O2 wjile stirring. 30% H2O2 is preferred, if all you can get is 3% then reduce the amount of water in the reaction accordingly. If there's undissolved NaBr don't bother, it will eventually dissolve.

> BTW was my procedure ok besides the wrong Na that is?

Don't cool it right from the beginning, try to start at about 20°C, and once you see that there is a positive exothermic reaction start cooling as necessary to keep the temp in the desired range.

[foxy2]

"I hope the other 40% of THF didn't turn into evil peroxides "
Yea it would suck to blow yourself up!!!  

Could you not just wash out any peroxides with water?
Flood post reaction mix with water and extract out the GBL with DCM, you will also get the THF but I think the peroxides will stay in the water.  Just wash the DCM extract a few times.  Anyone know for sure?

Then dry the DCM/THF/GBL and distill it to purify the goods.  But don't distill to dryness, just to bee safe.


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[terbium]

Organic peroxides are generally soluble in organic solvents.

[Prdy2GO]

Thanks Osmium,
Started all over this time half scale of the previous post.
currently stirring in H2O2 one drip about every 2-3seconds the temp has been at 15c for the last 10 hours adding H2O2 raised the temp 1c at about 10ml addition point. I an useing ~.50 mole (57mml)30% H2O2 I looked up in Vogels about the explosive tendencies and how a protective shield should be used. So I moved it next to a sliding glass door checked and set the fire extinguisher near by and put on my leather jacket and black neoprene gloves;just in case...
Don't look at me I didn't do it!

[Prdy2GO]

    
Poster: Osmium
Subject: Re: Easy Oxidation of THF to GBL

"Well, I have a few grams of RuCl3 at home, but since it fell in my lap by divine inspiration"

Per haps we share some divine spirit as It just so happens that 50g of rubidium chloride manifested in my presence. I had been wondering what it wanted to be when it grew up. I dont want to waste it the gooing price is 354.00 as listed in something I had retail mom and pop shop. Is there a reference on line or could some one post it please? I think I will do a search on Rubidium and see what I come up with.
Thanks
TTYL

Don't look at me I didn't do it!

[foxy2]

Ru is Ruthenium, and it is not in any way similar to Rubidium except for the spelling.
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[Rhodium]

RuCl3 is a very good safrole isomerization catalyst (see my isomerization FAQ).

[Prdy2GO]

Can Fe2SO4 be used insted of FeSO4 what is the diff? one II the other III
Don't look at me I didn't do it!

[Bwiti]

  Anyone here ever try oxidising THF with dichromate/H2SO4, then extract with ether?
  Split a piece of wood and I am there. Lift a stone and you will find me.

[Rhodium]

Bwiti: Do you have any references for that? The biggest problem with all these oxidations is that you don't want to oxidize the GBL further to succinic acid, which happens to some extent with all the oxidants tried for this reaction.

[Bwiti]

"Bwiti: Do you have any references for that?"

  No, it was just an idea. I'm completely miserable, because a grignard that I attempted was a complete failure for no apparent reason. At the moment, life fucking sucks, and I was looking for an easy way to create GBL, so I could get blissed out of my fucking mind!
  Split a piece of wood and I am there. Lift a stone and you will find me.