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12AX7
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Ah, I've got some solutions that dark. 
My primary batch of liquor must have a lot of other stuff in it, though.. the meniscus is still see-through-able, and the color is deep purple, but
not much deeper in color than, say, a concentrated CuCl2 solution is green (considering purple is a darker color than green).
Tim
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mericad193724
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I am working on some KMnO4 now too...
I fused 20g NaOH and 20g MnO2 for 1/2 hour and added the green sodium manganate to 300ml of water and then added 25g KCl. I heated up the mix and
bubbled CO2 gas through the mix while it was very hot. I let it sit for 1 week so the auto oxidation happens and bubbled CO2 through it
again...ITS REALLY PURPLE!!!!
My question is can I filter the solution through paper filter paper, or will the KMnO4 oxidize the paper and I will loose a lot of my
product?
thanks
Mericad
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12AX7
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It reacts with paper. Matter of fact you can dab some MnO4 solution with paper and watch the color change as the purple neutralizes.
Oh, an addendum to this thread -- I decomposed the permanganate solution and crystallized it out. I got about 50g total NaSO4, NaCl and KCl from the
solution and a pile of guess what... maybe a few grams of brown crud. 
Tim
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mericad193724
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SOoo CLOSE!!!
I have been continuing my project of making KMnO4 and I was really close today, but failed!
I decantated my KMnO4 solution that was really dark and boiled it from 250ml to 50ml. I added 200ml 100% nail polish acetone to this and heated to
dissolve all the KMnO4; this was followed by a decantation.
This acetone solution was pretty dark and I boiled it down expecting to crystallize KMnO4 crystals at the end... I left and returned when the liquid
was down to about 75ml, but it was clear!!!! With a lot of black precipitate (MnO2).
I must have all decomposed into MnO2!!!!
What caused this???? I realized that the Acetone was denatured with Denatonium Benzoate, could the KMnO4 have oxidized it? The other culprit could
have been the earthenware piece of pottery I put in as a boiling stone. I don't think the KMnO4 changes the acetone itself.
Here are some pictures...
 The KMnO4 solution after standing for one week but before being decantated from all the MnO2
 The KMnO4 solution after bubbling CO2 into it twice.
 KMnO4 in acetone, slightly lighter color (should be ONLY KMnO4).
 The end result a clear solution with a good amount of black
precipitate.
What caused the decomposition, was it the Denatonium Benzoate? Boiling Stone Earthenware Pottery? Or acetone?
We are so close to making KMnO4 a practical synthesis!
I will retry the experiment if I can figure out my mistake.
Mericad
[Edited on 24-11-2006 by mericad193724]
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Aqua_Fortis_100%
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Really Sorry by disturbing this old thread again, but i think , i've noted a few things..
some days ago, i'm traveled the Frogfot page about dichromate synthesis and see the
reaction:
| Quote: | If first step of reaction is carried out without a base, dichromate will form directly, however, this will produce lots of toxic NOx. I believe
reaction will go as follows:
Cr2O3 + 2KNO3 --> K2Cr2O7 + 2NO
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so, the follow can exist (???):
MnO2 + KNO3 --melting--> KMnO4 + NO
when i see the possibility of such reaction, i'm turned very happy..
Although the very bad properties of the NO<sub>x</sub> to the health, many byproducts can be made easily, if anyone have the right stuff
on hand to control these unwanted toxic gases.
And If the person goes out throgh the NO (to oxidize it, all of the gas or partially to NO<sub>2</sub> the O2 supplied by, e.g. an OTC and cheap aquarium pump or another device),theoretically the amateur chemist can (i
think)obtain:
- nitric acid (extra O2 supplied and condensation, following by the freedom of the waste gas through a outside place or absorbing it with some proper
solution);
- nitrites (unfortunately, i have no idea how the person can adjust the O2 inlet , to form equimolar amounts of NO and NO<sub>2</sub> (NO
+ NO<sub>2</sub> <---> N<sub>2</sub>O<sub>3</sub> );
- "lead chamber" process, to catalysis the SO<sub>2</sub> oxidation and to obtain H<sub>2</sub>SO<sub>4</sub> or
maybe , hopefully , even oleum ;
- anything more interesting (???)
but after, thinking about, i see only a problem: i think which without proper equipment, the yield of KMnO4, originally desired, can be quite low,
since the manual stirring should be forbidden ( NO<sub>x</sub> = death
).. so, i'm planning also create a mini improvised eletric stirrer , such as mini-engines of toy car... IIRC should exist a thread lying here, so as
soon as possible, i will search.
what about this reaction, is possible ???
thanks
EDIT#2: the gas , just regenerating (big??) parts of the original nitrate decomposed by the reaction, just absorbing in an alcaline solution... (the
only problem can be the "suckback" desgraceful problem)
i can not see if is feasible scales up this.. MAYBE..
[Edited on 4-6-2007 by Aqua_Fortis_100%]
"The secret of freedom lies in educating people, whereas the secret of tyranny is in keeping them ignorant."
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12AX7
Post Harlot
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Similar thing happens with chlorate -- 2KClO3 + Cr2O3 = K2Cr2O7 + O2 + Cl2. I tried running it with O2-neutral stoichiometry (using KCl as a
potassium source) and got green remainder, even with the help of some additional KClO3.
Back on topic, MnO2 of course decomposes chlorate, so that's no good. One could try adding KClO3 or KNO3 to a molten KOH / MnO2 slurry, but that's
not far from the usual synthesis.
Tim
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Aqua_Fortis_100%
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thanks for the share, 12AXT.
I'm really interested in this and will try as soon as possible (still in the "MnO<sub>2</sub> recovery from battery").. the fact is which
here KMnO<sub>4</sub> is very expensive (10 100mg tablets (1g) = $$$$$ ) and the method using a base seems to me to be a little bitc* to
purify and clean the materials... and i will like to experiment new things..(but i will try also the "conventional" method, to see what good will be
the product. (using NaOH - KOH is something rare here  ))
another thing i probably will like in melting these stuffs without a base ,as i say ,is the possibility in make others good products at same time.
although ,another possible BIG problem i see is ,maybe, the KNO<sub>3</sub>/MnO<sub>2</sub> coming too hard to be stirred..
i'm remembering now when i tried a sodium nitrite syntesis with NaNO<sub>3</sub>/Ca(OH)<sub>2</sub>/graphite .. the stuff
(NaNO<sub>3</sub> beginning to melt, but when i progressively added
lime/graphite become to hardening and the stirring impossible to do.
( 2 NaNO<sub>3</sub> + Ca(OH)<sub>2</sub> + C ---> 2 NaNO<sub>2</sub> + CaCO<sub>3</sub> +
H<sub>2</sub>O )
so what device you used to stirr the thing releasing toxic Cl<sub>2</sub> (the reaction using chlorate you mentioned)???
what you sugest to begin?
Thanks again.
"The secret of freedom lies in educating people, whereas the secret of tyranny is in keeping them ignorant."
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12AX7
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Well, the dichromate synthesis starts off as fluidized powder, so enough gas is given off that it remains liquid. At a critical point, it stops
gassing and "combusts", turning orange. The potassium dichromate melts around red heat.
Tim
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Chemophiliac
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So, what are the properties of Na2MnO4 or K2MnO4? I assume it decomposes in warm water. Also, does it have perculiar magnetic properties?
Additionally, could someone tell me if my K2MnO4 synthesis method will work well? I would like someone with more knowledge then me to evaluate it.
Essentially, my synthesis of K2MnO4 could be written as following:
4 KOH + 2 MnO2 + O2 --> 2 K2MnO4 + 2 H2O
How could I make KMnO4 from this without having soluable components like KCl or K2SO4 left over?
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The_Davster
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Yeah, that will work, but not well, and probably only isolatable yield in some sort of industrial furnace. In practice oxygen can only react at the
surface of the melt, which is why something like KClO3 is added as it decomposes releasing oxygen throuought the mass oxidizing to manganate. I tried
it at one point without oxidizer and was left with only the surface oxidized. See the posts I made last year on the second page of this thread.
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12AX7
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You can't- think about it, you have excess K, it has to be paired with something.
Na2MnO4, as near as I can tell, is stable (I've had it up to red heat and it remains deep green), but hates water.
Ya know, after my experiences with chromate, I may have to try permanganate again. As I recall, I omitted any oxidizer -- it turns green on its own,
but so doesn't chromate. But there's a big difference between the drab yellow sort of color you get on the surface of a chromate fusion, as compared
to the throughly deep red you get from a pure potassium dichromate melt. Likewise, the drab, exceedingly dark green color may be so dark due to
Mn(IV) (MnO2 or manganites). I'll have to try it again with KClO3 (my only prodigious oxidizer...next to that 5lb jug of KMnO4...er yeah...anyway...)
and see what happens.
Ooh, and it's a source of potassium. Lemme see...
3 MnO2 + NaOH (shit, I don't have any more NaOH...I need to find some*) + KClO3 = 3 K2MnO4 + NaCl + 1/2 H2O, hmm that needs about 5 KOH and another
2.5 H2O to balance, doesn't it.
Tim
*Red Devil lye is off the shelves now. A little farther down the shelf I saw a big heaping bucket of Rooto Number 2, which claimed 86% NaOH or something. Any idea what the other 14% are?
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Aqua_Fortis_100%
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Guys, thanks a lot for the great amount of good info.. armed with this knowledge i will save LOTS of money!!! Permanganate is very good stuff for pyro
displays , and great fun things can be made.
I will probably try synthesise small amounts in different ways in this weekend if the time gets good.
unfortunatelly , i can't buy or get anything chromium based to try dichromates, because these things were forbidden by local law because of *somewhat*
carcinogenic nature... shi* state of burocracy!
any idea?
| Quote: | originally posted by 12AXT:
*Red Devil lye is off the shelves now. A little farther down the shelf I saw a big heaping bucket of Rooto Number 2, which claimed 86% NaOH or
something. Any idea what the other 14% are? |
sorry by this little off topic, but, isn’t the “Rooto” stuff a sulfuric acid based product ?(better yet question: are in the US (which i
assume you live) , ALL drain cleaners based on beautiful sulfuric acid ? )(UNFORTUNATELLY , here this stuff is forbidden..so the usual source is the infamous acid battery..)
although here this NaOH for drain cleaner purposes is readily avaliable.. some brands are 98% content
maybe the buffers of your rooto can be some usual : chlorides, quicklime and even (i see on the label of a generic brand on the shelves here) sodium
chlorate, etc,etc,etc. (The unknow chemicals in some products also up set me very much!!!)
[Edited on 6-6-2007 by Aqua_Fortis_100%]
"The secret of freedom lies in educating people, whereas the secret of tyranny is in keeping them ignorant."
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Chemophiliac
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Because this whole post is so long and confusing, could someone just sum up the whole reaction from MnO2 and K salts all the way to KMnO4 in one
reply? Thanks, much would be appreciated. What is my best bet for getting a high kield of KMnO4 from the original reactants. I want to make KMnO4 so I
can use it here for various lab procedures, like as an oxizing agent, for making exotic permanganates. KMnO4 is very effective in redox reactions so I
can get other metals up to high, sometimes unusually high (for a particular elelment- like Ag++) oxidation states, as my chem teacher once told me.
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The_Davster
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Walton's Inorganic Preparations
http://www.sciencemadness.org/library/index.html
Full synthesis is in that book.
(my DJVUviewer appears to be broken)
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12AX7
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Ok-
So, you need some source of manganese, obviously. MnSO4 and MnO2 are common fodder. In the former case, you'll want to precipitate some form of
"non-salt" manganese, like MnO2, which would be through a combination of base and oxidizer. You might go this route:
MnSO4 + Na2CO3 --> MnCO3(s) + Na2SO4(aq)
MnCO3 can be (should be, anyway!) good to roast in air to at least Mn2O3. It may oxidize to that or MnO2 with peroxide, but I don't know if the
decomposition of peroxide is more probable (does Mn(II) catalyse peroxides?).
Anyway, once you have a manganese oxide, you need to 1. oxidize it and 2. add lots of base. The typical reaction is:
2 KOH + 2 KNO3 + 2 MnO2 = 2 K2MnO4 + 2NO + H2O (Unbalanced: N can go from +5 to 0, while Mn goes from +4 to +7, so the stoichiometry is complicated
and I won't write it out.) You'll probably have an excess of base.
Finally, you need to make it into permanganate. This takes a dash of acid and oxidizer. You might use H2SO4, HCl, HOAc, H2CO3, etc., and atmospheric
O2 (essentially, ignore it) for the oxidizer. Do it hot so it gets nice and concentrated, then cool it near 0C to precipitate most of the KMnO4 (some
2.5g/100ml solubility!). You may also filter it to remove excess MnO2, though you'll probably need an excellent filter to do so.
Tim
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DerAlte
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A belated comment to "mericad193724" post above - does not acetone from 'nail polish remover' also contain ethyl acetate? KMnO4 oxidizes primary
alcohols to acids and secondary alcohols to ketones, if memory serves. (Organic chemists please correct if wrong). If ethyl acetate is present, isn't
it likely that KMnO4 will oxidize it to acetic acid? KMnO4 goes for double C=C bonds - or alkynes - with vigor. It doesn't usually attack a single
C-C band but can attack a C=O bond but usually leaves most ketones alone, and is a favorite for actually producing them.
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CRK
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Temperature
Is the temperature strictly kept below 10C to prevent a runaway reaction or does a high temperature lead to unwanted byproducts like dichloroacetone?
Edit: Sorry, I had two tabs open for science madness and realized I posted this comment on the wrong thread.
[Edited on 4-11-2014 by CRK]
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AJKOER
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Here is an interesting comment I happen to read in Atomistry (see http://oxygen.atomistry.com/chemical_preparation.html ) that appears to suggest a particular favorable temperature. To quote:
"When a mixture of manganese dioxide and sodium hydroxide is heated to dull redness in a current of air, sodium manganate is formed:
4NaOH + 2MnO2 + O2 = 2Na2MnO4 + 2H2O.
The absorption of oxygen begins at 240° C., the rate of absorption increasing with the temperature, the optimum temperature being 600° C. The
product, on treatment with steam at 450° C., evolves oxygen, sodium hydroxide and manganese dioxide being regenerated:
2Na2MnO4 + 2H2O = 4NaOH + 2MnO2 + O2.
The foregoing reactions were made the basis of a commercial method for the preparation of oxygen from the air, but, owing to the short life of the
solid phase, the process has not proved particularly successful. "
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Some speculation on alternate paths, starting with the cited reaction:
2Na2O2 + 2H2O = 4NaOH + O2
and noting that the products are in the first referenced equation above, upon substituting therein, we could speculate that:
2Na2O2 + 2H2O + 2MnO2 = 2Na2MnO4 + 2H2O
Or, an implied direct action of Sodium peroxide (which can be formed from the action of oxygen at around 300 C on Na2O, which can be created by
heating Na2CO3 to 851C) on MnO2, or at least in the presence of water vapor:
Na2O2 + MnO2 --H2O Vapor?--) Na2MnO4
[Edit] Apparently, not too speculative as I just found this cited one pot reaction on SM to quote DerAlte at http://www.sciencemadness.org/talk/viewthread.php?tid=8480&a... :
"With Na2CO3 instead of NaOH, one might get
Na2CO3 + MnO2 + NaNO3 --> Na2MnO4 + CO2 + NaNO2
There is a very large difference between Na2CO3 in solution – which is mildly alkaline – and dissolved in NaNO3. There are no OH- ions. The
presence of OH- seems essential to avoiding decomposition of magnates and also nitrates. In general the hydroxide must always be in excess of
stoichiometric.
Hence I am very surprised you managed to get oxidation at 800C. which is a temperature very noticeably cherry red in daylight, and also that you
managed it with sodium carbonate. Further, you probably had only somewhat impure Mn2O3 and not dioxide."
where the strongly heated Na2CO3 supplies the Na2O and the NaNO3 the required additional oxygen to form the Na2O2. Also, found another reference http://www.allreactions.com/index.php/group-1a/natrium/sodiu... citing my speculated reaction and even the required temperature, to quote:
" Na2O2 + MnO2 = Na2MnO4 (400—500° С) "
The obvious problem with this preparation is the over 800 C required temperature for the thermal decomposition of the Na2CO3 directly to Na2O.
However, ball milling the Na2CO3 and MnO2 may provide a path to a much lower required temperature (400-500 C) based on mechanochemical processing (see
https://www.google.com/url?sa=t&source=web&rct=j&... ). The authors claim on page 22:
"In contrast to the carbonate decomposition in the non-milled mixture (Fig. 6d, 0 h, 400–800 °C), occurring in several steps and in a broad
temperature range, which is characteristic for a physical mixture of Na2CO3 and Nb2O5 particles (Jenko, 2006), the mixture milled for only 1 hour
releases CO2 in a much narrower temperature range, i.e., 400–500 °C (Fig. 6d, 1 h). We attribute this effect to the smaller particle size after 1
hour of milling, which is known to decrease considerably the decomposition temperature of Na2CO3 in the Na2CO3–Nb2O5 mixture due to reduced
diffusion paths (Jenko, 2006). In comparison with the 1-hour milled sample, upon milling for 5 hours only small changes are observed in the shape of
the EGA(CO2) peak (Fig. 6d, 5 h, 400–500 °C)."
As a sidebar, per Atomistry http://sodium.atomistry.com/sodium_peroxide.html one must avoid MnO2 containing any Carbon (as would be the case in a dry cell battery) as "It
[Na2O2] is reduced to sodium [actually Sodium vapor per another source] by charcoal or carbides of the alkaline-earth-metals."
-----------------------------------------------------
Also, if one used NaO2 in place NaO, further and seemingly unsupported speculation:
NaO2 + MnO2 --??--) NaMnO4
and, even more interesting would be replacing the Sodium salts with their Potassium counterparts.
Unfortunately, per Wikipedia on Sodium superoxide (see http://en.m.wikipedia.org/wiki/NaO2 ), its preparation may be challenging, to quote:
"NaO2 is prepared by treating sodium peroxide with oxygen at high pressures:[1]
Na2O2 + O2 → 2 NaO2"
However, if one assume the the formation of NaO2 provides a possible pathway, making it in situ implies heating the mix with the addition of oxygen
under pressure. This could be performed by adding an extra amount of a dry salt that produces O2 on heating (like KClO3, but certainly not in the
presence of any carbon as it will sensitize the chlorate to explode) and sealing (but, with some pressure release mechanism like a cover on which a
weight is placed) the reaction chamber to pressurize the liberated oxygen (where I am assuming, this will not cause the heated KClO3, for example, to
explode, but I would institute safeguards assuming such a scenario for safety).
[Edited on 9-11-2014 by AJKOER]
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AJKOER
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Ok, I just found something I think is exciting. No need for Na2CO3, just NaNO2 as per this source http://books.google.com/books?id=2BpMo7HpXzIC&pg=PA150&a... pages 150 to 151, it decomposes to Na2O when heated in the open to allow venting
of the NOx to Na2O and even Na2O2 in a stream of inert gas (or air) at 330 C, but under 350 C at which point the Sodium peroxide decomposes back to
Na2O (see http://www.allreactions.com/index.php/group-1a/natrium/sodiu...), to quote:
" 2 Na2O + O2 = 2Na2O2 (250—350° С, р) "
Over heating would require one to reheat the mix at the indicated lower temperature range in the presence of oxygen.
-------------------------------------
Prior referenced success using a mix of Na2CO3 and NaNO3 may actually be largely due to the presence of NaNO3 as at 600 C the equilibrium reaction:
2 NaNO3 = 2 NaNO2 + O2
and the favorable pathways via Sodium nitrite, per above, on cooling to a lower temperature.
[Edited on 14-11-2014 by AJKOER]
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