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runlabrun
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thf oxidation
Just a question about the various oxidation pathways for thf, producing gbl.
Sodium bromate:
Reagent: NaBrO3, NaHSO3
Solvent: H2O
Time: 16.25 hours
Temperature: 20 C
Yield 68%
Ref. 1 6148927; Journal; Sakaguchi, Satoshi; Kikuchi, Daisuke; Ishii, Yasutaka; BCSJA8; Bull.Chem.Soc.Jpn.; EN; 70; 10; 1997; 2561 - 2566;
or -->
Reagent: aqueous sodium bromate
Catalyst: 47% hydrobromic acid
Solvent: CH2Cl2
Time: 5 hours
Temperature: 35 C
Yield 67%
Ref. 1 5934286; Journal; Kajigaeshi, Shoji; Nakagawa, Takashi; Nagasaki, Noritaka; Yamasaki, Hiromochi; Fujisaki, Shizuo; BCSJA8; Bull.Chem.Soc.Jpn.;
EN; 59; 3; 1986; 747-750;
But also what about :
Reagent: Mn2O7
Solvent: CCl4, acetone
Temperature: -45 C
Yield 86%
Ref. 1 5689808; Journal; Troemel, Martin; Russ, Manuel; ANCEAD; Angew.Chem.; GE; 99; 10; 1987; 1037-1038;
or -->
Reagent: ZnCr2O7*3H2O
Solvent: CH2Cl2
Time: 1 hour
Ambient temperature
Yield 70%
Ref. 1 5572812; Journal; Firouzabadi, H.; Sardarian, A. R.; Moosavipour, H.; Afshari, G. M.; SYNTBF; Synthesis; EN; 4; 1986; 285-288;
Does anyone have any comments on these methods?
How could Mn2O7 be prepared? from MnO2?? KMnO4? keeping it OTC....
Zinc dichromate wouldnt be to hard to make, adjust the normal dichromate synth method to replace KOH with Zn(OH)2 and this would produce the desired
reagent.
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runlabrun
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lapse of memory....
2KMnO4 + 2H+ --> 2K+ + Mn2O7 + H2O
So...
2KMnO4 + H2SO4 --> K2SO4 + Mn2O7 + H2O
How could you seperate Mn2O7 from the post rxn mixture?
-rlr
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BromicAcid
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There is some information on Mn2O7 avalible in another thread here that you should read prior to attempts to use it in synthesis. It is essentially a covalent compound and is therefore not too soluble in the
aqueous phase, a layer of it usually separates out. I would hardly consider this OTC though, it requires carbon tet which I've had a hell of a
time trying to track down.
As for making ZnCr2O7, zinc hydroxide will not work as a replacement for potassium hydroxide, the properties of these two hydroxides are distinctly
different and this substitution would be next to impossible. Zinc dichromate appears to be very soluble in cold water and decomposes in hot so that
represents some prepratory problems. Mixing CrO3 with Zn(OH)2 may work in the presence of water. CrO3 readily made if you could pull off the
dichormate synthesis in the first place with KOH provided you have acess to H2SO4.
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skippy
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THF + TCCA
Here's something from the usenet:
"
Juenge and Beal, in Tetrahedron Letters No. 55 pp 5819-
5820 (1968) described a method of oxidizing ethers to esters in one step.
They used trichloroisocyanuric acid (which (conveniently enough) is in some
swimming-pool chlorination chemicals) in a 3 molar excess of water to
oxidize a variety of ethers to the corresponding ester. Conditions were
3 degrees C, and a reaction time of 3 - 20 hours, depending on the specific
ether
"
I've read the paper mentioned and, sadly, it is no more in depth than the above quotation 
Anybody have any thoughts on this method? The ethers oxidized in the paper were all non-cyclic, but maybe its worth a shot.
PS I found PVC glue at the home depot that contains only THF and polyester resin. Should be easy to separate. The price was around 10$ cdn for a
little less than half a litre.
[Edited on 5-1-2005 by skippy]
[Edited on 5-1-2005 by skippy]
[Edited on 5-1-2005 by skippy]
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runlabrun
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Bromic:
I was thinking CCl4 wouldnt be to hard from the information in your thread on it. Calcium cyanamide from urea and calcium carbonate heating, and
reaction with HCl:
CaCN2 + HCl(g) ---> CaCl2 + CCl4(g) + 2NH3
The OTC dichromate synthesis is easy to complete, i have used it many times, although not a very cost effective route... And access to conc H2SO4 is
no problem whatsoever...
And thanks im reading the Mn2O7 thread now, i didnt seem to find it when i was searching here..... whoops!
Skippy:
Interesting method, anyone heard of it?
Worth a shot yeah but THF resources are thin unless you work in the lab, someone with easier access might want to try it...
-rlr
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Mephisto
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Skippy's method works also with the 1,4-butandiole, but I doubt that it is easier to get for you.
1,4-butandiole + TCCA to find in:
Synth. Commun., 25(5), 719-724 (1995) - Convenient Synthesis of Lactones by the Reaction of Diols with N-Haloamides
Syn. Commun., 33(12), 2003-2009 (2003) - The Oxidation of Primary Alcohols to Methyl Esters and Diols to Lactones Using Trichloroisocyanuric Acid
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runlabrun
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Ok, ive read the Mn2O7 thread and looked around a bit in my resources and texts.... i think i understand... i think.... 
If conc sulphuric acid is added to a sep funnel and KMnO4 is added Mn2O7 will be formed as per the reaction mentioned above... would this be soluble
in sulphuric acid or layer? The layer would be on the bottom right? 2.4g/mL for Mn2O7 compared to 1.8g/mL for H2SO4.
You could then add the Mn2O7 quickly to a distillation flask containing THF in CCl4/Acetone sitting in a dry ice bath (sublimating CO2 is -57oC the
temp differece wouldnt matter would it?).
1- Does Mn2O7 detonate with CCl4?
2- In this proceedure were mixing acetone and Mn2O7.... boom? or does the CCl4 prevent this from happening?
3- CCl4 and Mn2O7 at these temps would be solids... would the rapid freezing of Mn2O7 from the room temp reaction cause it to detonate? or i could
slowly cool the Mn2O7 and CCl4 in the flask in the dry ice bath and add the Acetone/THF mixture....
The details provide no times for the reaction, also no amounts are noted.... would it be:
2THF + Mn2O7 --> 2GBL + 2MnO2 + H2O ??
How much of each solvent?
So once this is complete the MnO2 can be filtered out of the mixture and GBL distilled to relative purity.
Sound reasonable? or a pipe dream?
-rlr
[Edited on 6-1-2005 by runlabrun]
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cyclonite4
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skippy, there is some info in the THF thread about extracttion of THF from PVC pipe glue: http://www.sciencemadness.org/talk/viewthread.php?tid=2437
\"It is dangerous to be right, when your government is wrong.\" - Voltaire
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runlabrun
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Thanks for the link.
I had already read the thread for the pvc solvent information however what i did just notice was the orgsyn link to 2-Furaldehyde.....
Could we go 2-Furaldehyde --> GBL if so by what reagent? the furfural would have to be saturated to get rid of the double bonded carbons and the
aldehyde oxidised to form the lactone.
-rlr
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skippy
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Ok, the glue I was talking about earlier is called Oatey X-15 Bonding adhesive "for PVC sheeting". "CONTAINS: tetrahydrofuran,
Polyester resin."
It comes in a blue pint can, and I found it at the home depot. I'll let you know how the separation goes
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skippy
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THF distillation
I washed the glue several times with about an equal volumes of water. The glue turned into a ball of putty floating in the water with the washing.
The putty was discarded and the wash water distilled. The distillate's SG was measured to be around 0.88 or so, which matches with THF's
density. I stopped the distillation early and spilled some condensate and still managed to get 200 mL of THF from half litre of glue.
[Edited on 27-1-2005 by skippy]
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mick
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I used to separate organolithium stuff from the THF organics by adding water to quench the reaction and then saturating with salt. Extract and then
dry with anhydrous MgSO4. The THF was distilled off under vacum. I never noticed condensation and the samples seemed to be dry.
mick
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skippy
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Well, I've done two micro reactions and have learned that the TCCA should be added gradually. First test tube reaction: I added all of the TCCA
in one minute, the TCCA had been powdered. Within less than a minute yellow chlorine gas was pouring out of the test tube and the THF and water were
boiling out! I thought the problem was the powdering so I tried again with a single mini puck of TCCA and the reaction didn't start heating up
until after 40 minutes or so. This time the reaction didn't boil over and only got up to around 40 C, so in the morning I took the post reaction
mixture and evaporated it in a dish and was left with a rubber tasting goop. Interesting
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newboy
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Ive got 20 ltrs of THF and im in the process of getting potassium bromide can someone help me with the next steps
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SecretSquirrel
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You need potassium bromate for oxidation, but massive production of drug precursors is against forum rules, so I think you're on your own.
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spanner
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I ran across this information hope it help someone but i have a couple of questions related to it if anyone can help me
http://www.designer-drugs.com/pte/12.162.180.114/dcd/pdf/thf...
As i understand the process, the Ether is oxidized to the coressponding Ester Using NaBrO3 and NaHSO3, but it is not the actual reactants that
directly oxidize the Ether, A redox is set up between the NaBrO3 and NaHSO3 were one of the resulting products are Br anions which do the actual
oxidization of the ether.A chain reaction of BrO3 and Br is set up and as the reaction progresses it gets faster and self sustaining till the reaction
completes itself.
My question is could the oxidization take place simply by using NaBr or would it need something else to push the reaction forward.
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Nicodem
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| Quote: | Originally posted by spanner
As i understand the process, the Ether is oxidized to the coressponding Ester Using NaBrO3 and NaHSO3 |
According to the general procedure of the paper you linked the ethers get oxidized by HBrO3 formed in situ from KBrO3 and KHSO4 as acid. The
reaction requires an induction period due to autocatalysis (since one of the products, Br2, is also a catalyst for the oxidation). NaHSO3 has no role
whatsoever in the reaction as described in the general procedure (except for its use in the postreaction quenching of the oxidative species, but that
is after the reaction itself).
| Quote: | | My question is could the oxidization take place simply by using NaBr or would it need something else to push the reaction forward.
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NaBr can not oxidize anything since the bromide anions are already at the lowest chemically allowable oxidation state. The bromide anion can utmost
act as a reducent but never as oxidant.
[Edited on 20-12-2006 by Nicodem]
…there is a human touch of the cultist “believer” in every theorist that he must struggle against as being
unworthy of the scientist. Some of the greatest men of science have publicly repudiated a theory which earlier they hotly defended. In this lies their
scientific temper, not in the scientific defense of the theory. - Weston La Barre (Ghost Dance, 1972)
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spanner
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thanks nicodem that help to clear things up a bit
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spanner
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Can the Br be recovered after the reaction is completed
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Nicodem
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Recovered as what? You can not recover it as KBrO3 because it gets used during the reaction.
Recovering it as KBr would be a bit too much work for such a cheap chemical. Similarly oxidizing the left over solid from the distillation would give
Br2 which is a bit too hazardous to isolate for being worth the effort. In any case, if you would want to recycle it to KBrO3, then it would be a bit
stupid to use KBrO3 for the oxidation in the first place, since you would need electrolysis for the reoxidation of KBr. Therefore it would be much
simpler and cleaner to form gamma-butyrolactone from tetrahydrofuran/H2O in the presence of a small amount of Br2 or HBr by electrolysis instead.
…there is a human touch of the cultist “believer” in every theorist that he must struggle against as being
unworthy of the scientist. Some of the greatest men of science have publicly repudiated a theory which earlier they hotly defended. In this lies their
scientific temper, not in the scientific defense of the theory. - Weston La Barre (Ghost Dance, 1972)
Read the The ScienceMadness Guidelines!
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kmno4
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Pffff....
It is so dusty in here
Using NaBrO3 in oxidation of ethers is interesting in itself.
I am wondering about much cheaper K/NaClO3 as replacement for bromate.
BTW>
According to the first given reference, NaHSO3 can be a real reagent for such reaction.
Bull.Chem.Soc.Jpn.,1997, 2561 - 2566 in attachment
Oxidation of Diols and Ethers by NaBrO3/NaHSO3 Reagent
Attachment: asd.pdf (221kB)
This file has been downloaded 4514 times
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Nicodem
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That paper is quite interesting as it describes a simple method for synthesis of bromohydrines without using N-bromosuccinimide or other such
reagents. Surely an interesting method for BrO<sub>2</sub><sup>-</sup> in situ formation (bromites are rarely
commercially available if at all).
However, for the oxidation of ethers the reaction stoichiometry is not as good as in the earlier mentioned Tetrahedron, 56 (2000)
1905–1910, and thus less ester is obtained per mol of KBrO3. On the other hand the reaction is probably much smother to upscale and should be less
prone to runaways when compared to the Tetrahedron one which relays on an induction period (due to HBrO3 itself not being as efficient in
oxidizing the alpha-position of ethers as Br2, HOBr and similar later forming species are).
Probably you would encounter the same problem using chlorates. They themselves are probably much less reactive toward ethers when compared to Cl(I)
and Cl(III) species, so an induction period might be necessary to form enough reduced Cl species (or alternatively you might add a drop of HCl at the
beginning to start the autocatalytic cascade right away). However, alpha oxidation of ethers with Cl2, hypochlorites, TCCA and the like are generally
much messier than using comparable bromine based oxidants. All kind of nasty compounds can form and if your product is a liquid you might find it hard
to purify it even with a good distillation column.
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Methyl.Magic
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Don't forget that lactones are easily synthetised by deshydrogenating diols.
Have anyone ever tried to hydrate cyclic ethers to diols ??
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Nicodem
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I don't know if it is possible, but the last time it was discussed I could provide no one step method to transform cyclic ethers like THF into
terminal diols:
http://sciencemadness.org/talk/viewthread.php?tid=7765&p...
(though it's not like I searched the literature thoroughly enough to be sure of not having missed something simple)
…there is a human touch of the cultist “believer” in every theorist that he must struggle against as being
unworthy of the scientist. Some of the greatest men of science have publicly repudiated a theory which earlier they hotly defended. In this lies their
scientific temper, not in the scientific defense of the theory. - Weston La Barre (Ghost Dance, 1972)
Read the The ScienceMadness Guidelines!
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sonogashira
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I don't know if this has been mentioned before but since I came across the information I thought I would share:
THF oxidation to GBL with Ca(OCl)2 (63%) - Chem. Eur. J. 2007 13, 167-177 (Experimental on page 173 for preparing hexadeuterio analog
of GBL)
and same reagents with 68% yield - Tet. Lett. Vol. 23, No. 1 pp. 35-38 (1982)
Would attach the papers but i'm having trouble with that for some reason.
I haven't tried either of the procedures since GBL is legal in my country. Best of luck!
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