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Saerynide
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Solvent Free Permanganate Oxidation of Diols
According to Solvent Free Permanganate Oxidations by Shaabani and Lee:
"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.8,9 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.
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.
[B]Reductant (2 mmol) is added to a portion of the
oxidant (4 g) in a 25 mL round bottomed flask [/B]and
stirred magnetically until TLC analysis indicates a completed
reaction."
2 mmol of reductant per 4 g of oxidant?? Based on my calculations, I would need 233 g of KMnO4, 186 g of Al2O3, 47 g of CuSO4*5H2O for only 21 g of
alcohol.
At that rate, there wont be any alcohol left, as itll all be sopped up by the powder/paste  Is that supposed to be right?
Looking at it stoichiometrically, there should be be a 3:4 molar ratio of diol to permanganate. With the above figures calculated from the paper,
the molar ratio is something like 0.157:1
Has anyone tried the method in this paper? Should I use the stoichiometric ratio, or this insane ratio? It seems like a waste of permanganate to
me...
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Pomzazed
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This is the same question I'm wondering too! Even with the small scale experiment
Imagine how a solid lump of 4g look like and drop 2 mmol liquid reactant into it, which will just get absorbed right away into the powder to form a
paste, and then what?
" by washing the spent oxidant with an organic solvent"
with some inert one like DCM, i suppose. But wonder if the leftover pile after washing can be reused for some times.
Don't stare at me making fumes... I'm just experimenting with some gas...
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DJF90
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I doubt the leftover powder can be used again otherwise they would just employ the quantity needed to perform the oxidation with a slight excess. I
guess that to get the product you need to extract with organic solvent as stated. I was going to suggest that its supposed to be 0.4g of oxidant but
then that would give a 0.157:0.1 ratio of diol to oxidant, meaning the diol is in excess... I doubt that would be the case.
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Jor
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I have done a synthesis lately on university.
About 400mg of 2,4-dimethyl-3-hexanol was added to 2 grams of a 1:1 mixture of copper sulfate pentahydrate and potassium permanganate. The result was
a solid lump of material. 3 drops of 2M H2SO4 (NOT conc. H2SO4!) was added, and the flask was heated in a 85C (im not sure it was 85C, but it was
certainly well above room temperature!) water bath for 30 minutes. Next the reaction mixture was allowed to cool down, and the product was extracted
from the reaction mix by 4x5mL portions of DCM, and filtered (MnO2 was present in the extract).
The DCM was evaporated using the rotavap.
H-NMR and IR spectra indicated that there was no more alcohol present anymore, just 2,4-dimethyl-3-hexanone and a small amount of DCM.
So this definately works. And I think you need more CuSO4.5H2O than you stated...
[Edited on 27-3-2009 by Jor]
[Edited on 27-3-2009 by Jor]
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Pomzazed
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What is the role of CuSO4.5H2O in the catalyst? seems like Cu2+ doesn't do anything to the reaction.
Is it for providing limited amount (thus reaction step) of H2O from its hydrated water?
Don't stare at me making fumes... I'm just experimenting with some gas...
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Jor
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The CuSO4.5H2O will not use it's crystal water. You need high temperatures for that, or strong dehydrating agents, such as conc. H2SO4.
I think the Cu(2+) has no function, but the CuSO4.5H2O is there just to 'dilute' the potassium permanganate, but I'm not sure!
Does anyone has any ideas?
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DJF90
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It could participate as an oxidant. The Cu(II) could oxidise the substrate, reduced to Cu(I), which is then oxidised back to Cu(II) by permanganate.
But this is very unlikely, although IIRC silver ions can be used the same way in solution with persulfate ions
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Saerynide
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I also wondered about the CuSO4. I've found another paper that doesnt use the Al2O3 support (they use 50/50 KMnO4 and CUSO4 and had only a yield of
58%), but that paper also does not mention the role of Cu in the reaction...
Charles W. Jefford and Ying Wang. Selective, heterogeneous oxidation of alcohols and diols with potassium permanganate, J. Chem. Soc., Chem. Commun.,
1988, 634 - 635.
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unionised
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I wonder if the CuSO4.5H2O is there to prevent the sort of reaction that I'm sure many of us have done; the solvent free reaction of a triol with
permanganate.
There's a demo of it here (and there are lots of similar videos)
http://www.youtube.com/watch?v=RWzZoaAOE3Y
Adding an inert diluent would seem prudent. Adding something that can dissipate heat by losing water as the vapour might help too
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Paddywhacker
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So, what does the oxidation of diols yield, 1,2 diketones or cleavage of the carbon-carbon bond with the formation of two carboxylic acids?
Edit:-
I am thinking of what will happen to double bonds with a catalytic amount of osmium tetroxide. The OsO4 will convert the olifin to a diol. The KMnO4
will oxidise the reduced Os back up, making it useful in tiny amounts, and will also oxidise the diol up to whatever it oxidises it to.
mmmm.... need OsO4
[Edited on 29-3-2009 by Paddywhacker]
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Saerynide
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Quote: Originally posted by unionised  | I wonder if the CuSO4.5H2O is there to prevent the sort of reaction that I'm sure many of us have done; the solvent free reaction of a triol with
permanganate.
There's a demo of it here (and there are lots of similar videos)
http://www.youtube.com/watch?v=RWzZoaAOE3Y
Adding an inert diluent would seem prudent. Adding something that can dissipate heat by losing water as the vapour might help too
|
I was actually wondering about this. I'm worried I might set my lab on fire (imagine explaining that one to your advisor...) if I just added the
diol to the solid oxidant. Hence, I am going to go the "paste" way with the concentrated aqueous soln of KMnO4 like the paper says you can also do.
What do you guys suppose is the risk of fire if you went completely solvent free?
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Saerynide
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Ok, thank god I tried this on a small scale first before diving right into scaled up 400 g.
I used 4 g of oxidant (3.33 g of KMnO4, 0.67 g CuSO4), and added water to create a thick slurry. I dropped in a tiny amt (~0.5 ml?) of
1,4-butanediol and stirred the mixture. At first nothing happened, then suddenly about 15 seconds later, woosh! It all came boiling violently over,
generating tons of steam. I immediately dumped in copious amts of water to stop the reaction.
So if this is with water... imagine what would have happened with no water if you followed the paper? How did these people *not* set their lab on fire??
How would you recommend one proceed? Add (alot) more water? Or this reaction inherently unscaleable?
Maybe this is why no one uses this route, as easy as it sounds...
[Edited on 4/1/2009 by Saerynide]
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Paddywhacker
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I suspect that the water is the source of your problem. With a dry reaction the availability of the permanganate will be limited to the surface of
its crystals, as it would be largely insoluble in the reaction mixture.
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Jor
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First of all, the CuSO4/KMnO4 should be a 1:1 molair mixture (or mass not sure), at least that's what my uni notebook said. You used way to much
KMnO4!
Second why add water? Just add you alcohol, followed by 3 drops of 2M H2SO4.
See my experiment I posted above.
O yes, I forgot to mention the yield, If I remember right I think it was 450mg, but it still contained about 30-35% DCM. So say 300mg product, wich is
about 75% yield on very small scale.
Secondly, maybe the reaction was so vigorous, because it is a diol. Wiki says glycols (like ethylen glycol or glycerine) are highly reactive towards
potassium permanganate, maybe 1,4 butanediol is as well. Maybe try another alcohol, with just one OH-group...
[Edited on 2-4-2009 by Jor]
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PHILOU Zrealone
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Am I the only one to read correctly what is stated in initial post? 
"...to give a reagent that has previously been used extensively as a
heterogeneous oxidant in inert solvents."
--> This is thus heterogenic catalysis!
As unionised wrote, it would not only be prudent  but also needed to temper the
reaction by dillution (inert solvent will eventually reflux and so take the heat of the exothermic oxydation...
All of you know that terminal primary alcools will be oxydised first to aldehydes and finally to carboacids...secondary alcools will be oxydised to
ketons...in the case of glycols one can get dicetons and sometimes further oxydation with cleavage.
As overview:
R-CH2-OH --> R-CO2H
R-CHOH-R' --> R-CO-R'
R-CHOH-CHOH-R' --> R-CO-CO-R'
R-CHOH-CH2OH --> R-CO-CH=O --> R-CO2H + CO2
CH3-CH2OH --> CH3-CO2H and eventually HCO2H, CH4, H2CO3
If the heat is too strong, cleavage can occur because even if ketons are more resistant to oxydants than aldehydes, keto-enol equilibrium renders it
sensitive via the double bond quite sensitive to KMnO4...
CH3-CO-CH3 <--> CH2=C(OH)(CH3)
CH2=C(OH)-CH3 -ox-> HO-CH2-CO-CH3 <--> HO-CH=C(OH)-CH3
HO-CH=C(OH)-CH3 -ox-> O=CH-CO-CH3 -ox-> HO2C-CO-CH3 -ox-> CO2 + CH3-CO2H
-ox-> HCO2H + CO2
-ox-> H2O +CO2
By the same logic, Oses (polyhydroxy aldo/keto-compounds) will be oxydised to H2O and CO2 if too much heat or catalyst is used...this is what happens
when glycerol or glucose is mixed with KMnO4....maybe that with dillution the self heating is sufficiently reduced to keep the temperature low enough
to allow isolation of interesting polyfunctional molecules ... combinations of carboxy, keto, aldo and alcools...
The isolation of the acids, ketons, aldehyds might be a problem if:
-they are too reactive or soluble in water
-they do form complexes with Cu(2+), Mn(x+), Al (3+)...
-they do form unsoluble salts with Cu(2+), Mn(x+), Al (3+)...
[Edited on 2-4-2009 by PHILOU Zrealone]
[Edited on 2-4-2009 by PHILOU Zrealone]
[Edited on 2-4-2009 by PHILOU Zrealone]
PH Z (PHILOU Zrealone)
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Nicodem
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| Quote: Originally posted by Saerynide | Ok, thank god
I used 4 g of oxidant (3.33 g of KMnO4, 0.67 g CuSO4), and added water to create a thick slurry. I dropped in a tiny amt (~0.5 ml?) of
1,4-butanediol and stirred the mixture. At first nothing happened, then suddenly about 15 seconds later, woosh! It all came boiling violently over,
generating tons of steam. I immediately dumped in copious amts of water to stop the reaction. |
The whole point in using CuSO4.5H2O is in that you have a controlled source of H2O needed for the oxidation reaction. Why would then someone want to
add water? What you did is irrational. You first used a wrongly composed oxidant mixture with an enormous excess of KMnO4 and instead
of following the reaction progress you made it go runaway by adding the only component that must not be added, water. I really think you have a lot to
learn before you do something that stupid on a 400g scale! Have you ever saw what a mixture of glycerine and KMnO4 does when ignited? Imagine that
happening in a large glass flask. You better think if your quest for such a boring drug like GHB is worth of an injury. This is not the type of
reaction that can be scaled up from mmol to mol by multiplication.
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Globey
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Imagine using only nano-particled reagents...I bet you could eliminate many solvents, and make things quite a bit greener...not so simple, but
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Formatik
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Knowing the reaction of polyalcohols with KMnO4, one can not react diols and triols with KMnO4 in the solid state without a diluent and usually not
get a reaction (gas evolution and heat, and usually ignition). There was at least one thread about these kind of hypergolic reactions. Ethylene glycol
(ethanediol) ignites with KMnO4. Propanediol ignites, but reportedly takes longer than glycerin. So butanediol should also give some fireworks.
| Quote: Originally posted by Saerynide | | I used 4 g of oxidant (3.33 g of KMnO4, 0.67 g CuSO4), and added water to create a thick slurry. I dropped in a tiny amt (~0.5 ml?) of
1,4-butanediol and stirred the mixture. At first nothing happened, then suddenly about 15 seconds later, woosh! It all came boiling violently over,
generating tons of steam. I immediately dumped in copious amts of water to stop the reaction. |
In the paper the ratio (note for the solid oxidant alone) is either: 2g KMnO4 and 2g CuSO4.5H2O (by mass); or 2.50g CuSO4.5H2O and 1.58g KMnO4 (molar
ratio), depending on what they meant by "amounts". Unless stated otherwise, the more ancient literature would invariably mean parts by mass, but I'm
less familiar with the newer papers. They also talk of making a homogenous mixture and grinding them together. The reducer also isn't added all at
once, it's "added dropwise while the solid oxidant is tumbled using a magnetic stirrer". Read the instructions carefully. If having done all the paper
demands (proportions, intimate mixture, stirring, portion-wise addition), and you still get violent reactions, then you can conclude the procedure is
no good.
| Quote: Originally posted by Nicodem | | The whole point in using CuSO4.5H2O is in that you have a controlled source of H2O needed for the oxidation reaction. Why would then someone want to
add water? |
There is a watery paste mixture as an alternative to the solvent-free solid oxidant offered by the paper. Though yes, it was a large excess of KMnO4.
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Saerynide
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| Quote: | | Why would then someone want to add water? What you did is irrational. You first used a wrongly composed oxidant mixture with an enormous excess of
KMnO4 and instead of following the reaction progress you made it go runaway by adding the only component that must not be added, water....Have you
ever saw what a mixture of glycerine and KMnO4 does when ignited? Imagine that happening in a large glass flask. |
Yes, I have done the glycerin to solid KMnO4 demonstration quite a few times, and it is for that reason I'm wary of the whole "solvent free" idea. I
also know that adding a solution of KMnO4 and glycerin will not ignite, and hence the reason why I added water.
And Yes, I do know that I have a lot to learn. I am not a chemistry major, but a chemical engineer, so I know that my organic chem is not anywhere as
strong as those in the science. But I do have common sense and enough lab experience (I'm part of a research group), and I do understand the
complications of scale-up (the ChemE specialty  ) to not kill myself or injure
others. Hence, I am giving this a try and am proceeding with caution.
Finally, I did read the papers - I scoured both of them many times because I was trying to see if there was something I missed, but they really do not
mention whether the ratios are by mass or mol. I took them to be by mass, as most people would.
The Shaabani and Lee paper cites using equal amts of KMnO4 and a 20/80 mix of CuSO4*5H2O/Al2O3, made into a thick paste with water.
This ratio is 100/20/80 KMnO4/CuSO4/Al2O3. They cite 2 mmol per 4 g of oxidant.
The Jefford and Wang paper desribes using a 50/50 mix of KMnO4/CuSO4*5H2O heterogeneously with the 1,4-BDO dissolved in DCM (1 mmol in 50 ml).
I am not comfortable using such a large quantity of DCM over such a strong oxidizer (as I said before, since my org chem is far from bullet proof,
intuition tells me this doesn't sound like such a great idea), so I opted with the watery paste method ala Shaabani and Lee in the first trial. I was
still VERY uncomfortable with the huge excess of KMnO4...
I did stir, and I did drop in the meager 0.5 ml of 1,4BDO slowly. I added 1 drop, stirred, nothing, added 2 more, stirred, 15 seconds, woosh...
Apparently, that was not enough water, and I had every right to be uncomfortable 
--------------------------------------------------
Anyhow, I tried something else the second time around.
I used the same weight ratio (100/20 KMnO4/CuSO4) as the Shaabani paper, with no Al2O3, and I figured I would dissolve the diol in an excess of water
and slowly add the oxidant a bit at a time. Also, I would not follow their huge excess of oxidant, but instead use excess diol.
I did this for several reasons:
1) With a constant excess of water, it would not run away on me
2) Over oxidation would hopefully not be too much of an issue if I keep the diol in large excess
3) No point using Al2O3 as a solid support if its not solvent free (plus, I didn't have any on hand)
I found that indeed, a similar process was tried by someone else on the Hive. In the old thread, THF was dissolved in excess (and in a later trial,
equal amts) water and then an 80/20 mix of KMnO4/CUSO4 was slowly added, making sure to keep the heat down. They reported decent results.
I added 44g of 1,4-BDO to ~50 ml of water. I made a mix of 100/20 KMnO24/CuSO4 (like the Shaabani paper) and slowly scooped tiny amts into the
1,4-BDO with stirring. It turned pink and then faded to brown. As the process continued, the mixture became a thick slurry of MnO2. A few icecubes
were added over the course as the soln warmed up. The temp was never allowed to rise above ~45C (shower temp, judging by touch). By the end of 10
hours, ~37g of KMnO4 (not including the accompanying mass of CuSO4) had been added. The final volume was ~250 mL.
The slurry was filtered, giving a crystal clear and colorless filtrate. The cake was washed with more water and the filtrate saved.
The filtrate was extracted 3 times with DCM, each with 150 g of DCM. The DCM was dried with MgSO4 and was evaporated by pouring into a shallow dish
by the window still and blowing a fan over it (couldn't distill because all the fume hoods in lab were in use). As the DCM evaporated, the DCM
quickly became milky white. As it continued, a white crystal started to form. I was confused initially, but I soon figured it was unreacted 1,4BDO
that was frozen because the evaporating DCM removed so much heat (even water ice formed on the outsides on the dish ). When all the DCM was gone, I was left with a clear colorless liquid that was
slightly oily (but not as anywhere as viscous as 1,4BDO) and had a slight smell. The liquid did not evaporate, as drops left behind on glassware
remained oily for many hours. I would guess it contains unreacted 1,4BDO and lactone, but I have no sample of lactone to compare it to. Volume was
about ~25 mL
About 14 g of NaOH was dissolved in 40 mL water. It was slowly added to the extraction product. The soln heated up slightly, and became yellow and
slightly milky with some fine precipitate over time. It was left to stand for a few hours. Leftover base was neutralized with an excess of vinegar
(couldn't find my pH strips, so I added vinegar until it stopped being slippery and tasting like base). The resulting solution was boiled down. As
it boiled, the liquid became darker yellow. At some point, the liquid seemed to stop decreasing in volume and a very thick amber liquid was left.
The liquid seemed to crystalize rapidly on the beaker walls as it was swirled around. I was very confused and thought it must have been super
saturated. I heated it a bit more until it boiled and popped everywhere (boiling chips were of no help) and then I had to go, so I removed it from
heat and left it on the counter.
I came back to find the amber liquid as a solid beige block in the bottom of my beaker. It was waxy, and when crushed to a powder, the powder feels
almost oily. It smells sweet, bit of sour and kind of buttery? Its really hard to describe, but its a familiar smell I've come across in totally
non-chemistry related situations. Taste is salty, with a tiny bit of sourness. Having never seen Na oxybate, I can't make a comparison. I'm guessing
I have a mixture of lactone, 1,4-BDO, NaAc, and Na oxybate?
-------------------------------------------------------------
Now that I think about it, was it possible that the thick crystalizing amber liquid was a mixture of NaAc and molten Na oxybate? It really would have
helped if I had a thermometer... someone had one but she wasn't around for me to ask, and then I had a mercury one, but I was NOT
about to use that! It did not occur to me when I was heating it that it could have been a molten liquid and not a solution.
It also would have helped if I could locate my pH paper, but I figured excess acid (vinegar in this case) would just evaporate and so it really
wouldn't matter in the end.
I know the product is very impure and it would be extremely foolish to even try to test it. That is really of no matter to me, as I was, and still am
more interested in the process than the end result. The major possibility of having no product does not bother me, because science is a learning
process.
I would really appreciate it if someone would like to help me understand if I was on the right track at least, or, if I had gone wrong, where.
[Edit]: Formatting
[Edited on 4/7/2009 by Saerynide]
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Paddywhacker
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What you performed was an oxidation by permanganate in solution. I would hazard a guess that the CuSO4 played no part in the reaction.
The solvent-free oxidation discussed earlier would have had the advantage of a much easier workup .... no water ... no huge amount of MnO2 to filter
... just extract the solid reaction mass with dichloromethane.
In opting for solvent-phase oxidation over solvent-free oxidation you have missed an opportunity to explore a seldom-practised topic.
Edit:- I tried out the technique myself with propylene glycol.
3g KMnO4 plus 3g cupric sulphate were ground together in a mortar.
2g propylene glycol were added dropwise to the mortar with mixing and grinding over a time interval of seven minutes. The mixture lost its purple
colour and turned a dull brown/black. The mortar warmed up a little and the smell of burnt sugar was apparent
When all of the glycol had been ground in the mixture had the consistency of a heavy paste that turned hard on cooling.
The reaction mixture was extracted with 3 x 20ml of DCM. All of the particulate matter filtered out easily, and on evaporation there remained 0.36 g
of a glycerol-like oil that had a slight fruity smell.
Altogether a disappointing yield. It is possible that I got pyruvic acid formed and that remained bound with the metal oxides. Maybe I should have
acidified before the DCM extraction.
Edit again... the product gave a solid orange precipitate with Brady's reagent (2,4-dinitrophenylhydrazine), a positive test for ketones/aldehydes.
[Edited on 8-4-2009 by Paddywhacker]
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Saerynide
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Hmmm.... If the CuSO4 played no part in the aqueous reaction at all, then where could it have gone? The mixture has no blue color at all, ever in the
process
Could it have precipitated out as an oxide and mixed in with the MnO2? Being red and black, copper oxides could easily blend in.
Also, with the mmol scale of the solvent-free oxidation, it would be hard for me to actually learn much unfortunately. Assuming it doesn't run away
on me again the second time, I still can't analyze the results - I'm so not about to ask the post-docs to NMR a sample of this sort for me
Edit:
Hmm... Maybe I will give the solvent-free method (no watery paste this time) and with 50/50 KMnO4/CuSO4 another try when I have time this week
[Edited on 4/8/2009 by Saerynide]
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Paddywhacker
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| Quote: Originally posted by Saerynide | Hmmm.... If the CuSO4 played no part in the aqueous reaction at all, then where could it have gone? The mixture has no blue color at all, ever in the
process
Could it have precipitated out as an oxide and mixed in with the MnO2? Being red and black, copper oxides could easily blend in.
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Yes, when the permanganate is reduced the solution becomes alkaline and that precipitates the copper as its oxide. So the copper sulphate is acting
as a buffer, preventing the mixture from becoming too alkaline.
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Saerynide
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Ohhh!!!! It all makes sense now  I was wondering why the lactone didn't
hydrolyze into K-oxybate in the solution due to the KOH that was produced. So the KOH is mopped up by the CuSO4
So.... if I do this in aqueous soln again, would it be better to just skip on the CuSO4 completely and let the KOH hydrolyze the lactone? But then,
maybe separating the K-oxybate from impurities might be harder as it'll all be in aqueous soln - perhaps boil down and recrystalize from EtOH?
[Edited on 4/8/2009 by Saerynide]
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497
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Saerynide I think you misunderstood the ratios when you did your tests. I think the paper meant to say (it was terribly worded!) that the
KMnO4:CuSO4*5H2O ratio is always 1:1 rather than the 1:1 ratio being between KMnO4 and the mixture of CuSO4*5H2O and Al2O3, like you
interpreted it. Apperently when the optional Al2O3 was added it was always 4 times the amount of CuSO4*5H2O, so the ratio is really 1:1:4
KMnO4:CuSO4*5H2O:Al2O3. That would make more sense...
Assuming 3 moles of substrate are oxidized by 4 moles of KMnO4, 2mmol of substrate would require 0.42g of KMnO4. So if they used a little excess, say
0.67g of KMnO4 and added enough of the 1:4 CuSO4*5H2O:Al2O3 mixture to make an equal amount of CuSO4*5H2O to KMnO4, the total happens to come to near
4g... That seems to be good evidence of my interpretation... I would bet your yield would increase if you did it like that.. and maybe microwave it
too.
I'm assuming the reaction goes as follows:
4KMnO4 + 3C4H8O + 2CuSO4 --> 3C4H6O2 + 2K2SO4 + 4MnO2 + 2CuO + 3H2O
According to the above equation 632g of KMnO4 is used and 499g CuSO4*5H2O is used. So it makes sense that the paper used a 1:1 ratio.
[Edited on 9-4-2009 by 497]
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Saerynide
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OHhhh! *bangs head on keyboard*
I swear that was the most grammatically confusing paper I've ever read!
After Paddywhacker explained the precipitation of the copper, I started to wonder why they didn't add a stoichiometric ratio of CuSO4...
And now, the pieces finally fit. The mystery of the ratios has been solved! Thanks 497!
So by using a 1:1 wt ratio in the paper and thus having the CuSO4 in a slight excess, equilibrium will also be pushed towards the lactone instead of
oxybate Now I'm really interested in giving the solvent-free method another
try! Just think about not having to filter that MnO2 sludge Unfortunately, I
will still have to make do without the Al2O3... It's too expensive and I can't justify buying it to my prof ($90+ for 500g!!! wtf??)
Hopefully, it won't catch fire on me! And this time, I'll make sure to find my pH strips and thermometer *before* I start the second part (one's own
hand makes a crappy pH meter ) I'll be sure to report back the results.
Thanks for all the help everyone
[Edited on 4/9/2009 by Saerynide]
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