> chemistry > oxydants > making-high-conc-permanganate-by-manganese-electrolysis-scrap-science

A Simple Synthesis Of Permanganate

Scrap Science - 2020-11-18

We do our best to follow a 100 year old paper describing the synthesis of permanganate from manganese metal.

DOI of the paper: 10.1021/ie50141a012

Link to the video where we make manganese metal: https://youtu.be/wBWba_anewQ

The setup is very simple, using a separated electrolytic cell (with a clay pot diaphragm) and a 25% potassium carbonate electrolyte, we use a manganese anode to make permanganate at a high efficiency. In doing this, we were able to make approximately 1.5g of potassium permanganate as a 0.21M solution. Sadly, we don't manage to crystallise any pure permanganate from solution.

This electrolytic method offers some serious advantages over most other permanganate syntheses in that it offers a high efficiency and is capable of generating a highly concentrated solution (possibly getting close to saturation). It also doesn't require aggressive oxidisers or high temperatures. The only major downfall of this pathway is the fact that it uses manganese (or ferromanganese) metal as a starting material, which is a little difficult to get hold of. In the future, I'll definitely be revisiting this by attempting to make a manganese electrode from manganese sulfate (a much more available compound) and using that as the manganese source for the electrolysis stage.

This video is basically just a proof of concept for the process, so I haven't attempted to calculate the yield or efficiency of the reaction. Again, this is definitely something I'll revisit in the future with a bit more of a controlled setup, so stay tuned!

Daniel Matthews - 2020-11-18

This paper? https://libgen.lc/scimag/ads.php?doi=10.1021/ie50141a012 and would tracking the mass loss in your manganese electrode, next time, be informative?

Scrap Science - 2020-11-18

Yep, that's the one. I meant to put the DOI in the description but completely forgot.
And yes, measuring the mass difference of the manganese was actually part of the plan for this video, but again, I forgot to make an initial measurement. When I revisit this I'll be taking everything a little more seriously in terms of calculating yield and efficiency, so hopefully I won't forget again.

Daniel Matthews - 2020-11-18

@Scrap Science Great I look forward to seeing the next video, there isn't a lot of people doing electrochemistry on YT.

elektronik zımbırtılar - 2020-11-18

@Scrap Science can you pin this comment so people can find it easly

Scrap Science - 2020-11-18

@elektronik zımbırtılar Good idea, it should also show up in the description now too

Telectronics - 2020-11-18

@Scrap Science Yes I don´t know any other video making permanganates with electricity. Love your results and don´t be sad about the crystals I have seen a lot people who could not get crystals from it. Seems like it´s not an easy task for me. Maybe you have to oversaturate it with the production of a lot more over the time and just filter it.

davagain - 2020-11-18

Without seeing the date of the paper, I got a pretty good ballpark when you held up a page and I read a reference to Bakelite.

Kemster - 2020-12-10

Great process it seems like evaporating in a large wide glass dish would help. I'm wondering if using Bismuth and manganese as an anode would help. This chemical is so tricky it even reacts with filter paper which using glass wool is the only way

Greg Brown - 2020-11-18

I love your videos so much man keep it up I'm always looking forward to the next one!
I'm super interested in chemistry and learning new ways to make things
honestly I'm really surprised your channel isn't bigger than what it is but it definitely has the potential to grow huge

ElectricMudPuppy - 2020-11-25

As far as crystallization goes temp changes are a problem. You gotta dry it. I leave it open to the air in a dry place for weeks and it will grow crystals. Crystals don’t like to grow fast

Derek Beech - 2021-01-17

Is the permanganate in a high enough concentration to react with glycerin? Would give you a good idea of how well you did 💡😁👍

slamon ̇ ̇ - 2020-11-18

You sound more confident in this video, good job!
Also, have you ever thought of using magnetite as an anode in a chlorate cell? I've seen some posts on sciencemadness.org where a user was able to make a layer of magnetite on a piece of iron and use it for chlorate production. Apparently it didn't corrode a great deal. This could be a good source of cheap chlorate anodes.

Scrap Science - 2020-11-19

A magnetite anode looks very interesting, though it apparently involves reacting a 500C iron coating with steam in order to make a conductive layer, which is disappointingly outside my capabilities at this stage. I'll definitely keep this in mind for the future though, yet another reason for me to buy a proper furnace :)

Gerard Geer - 2020-12-02

Gday mate! New follower to your channel, love your work. I've been messing with home chem for a couple years now (mostly simple synthesis for crystal growing) and have had no luck whatsoever getting permanganate crystals to grow nicely, even through recrystallisation from pure crystals. Its an absolute nightmare of a chemical to crystallise from my (albeit small) attempts.
That aside, its awesome to see a cool synthesis method! I've been meaning to get more creative with electrolysis and you're giving me mad inspiration.
Keep up the awesome work!!

Zulqarnayeen Schaftler - 2020-11-18

is 'very tricky ''business''' lol cool video :))

Full Modern Alchemist - 2020-11-19

I was really rooting for you that you'd be able to separate the permanganate, sorry it didn't work out. I did a synthesis of this once but it was one of the high temperature variants. I had basically the same result. Lots of dark purple reactive solutions but no solid. I tried slow evaporation as well and that didn't work either. I just got a sludge of manganese dioxide and potassium hydroxide. If I revisit this and figure anything out you can be sure that I'll let you know.

Also - 2020-11-19

I read on wiki that pyrolysis of zinc acetate can give acetic anhydride, maybe you should try it?

Paweł Baranowski - 2020-11-19

Can you make HCl from NaCl (without acids) in next video?

mfsamuel - 2021-01-13

I think cycles of evaporation to a super saturation state, followed by cooling would have resulted in better crystals. Heat destroys permanganate crystals.

William Latinette - 2020-11-19

I really enjoy your videos. As a suggestion, could you please find some better illumination for your experiments? LED lights are so bright and cheap I'm disappointed that at times we can't really adequately SEE the results of your considerable work. Keep it up!

TreHazen F - 2020-11-18

Missed ya :3

Israel Burkett - 2020-11-26

If you freeze the solution you could pull a vacuum on it to sublime the water?

Edward Science Innovations - 2020-11-18

now all i need is manganese metal, the easiest way i can do is thermite reaction hope thisll work

Scrap Science - 2020-11-19

Yep, if you've got the ability to set up a thermite reaction, that's pretty much the ideal first step, hope it goes well!

MushRoom - 2020-11-18

Love your channel!

No Trace - 2021-02-27

Give this man a doctor title

XvAvX - 2020-11-18

Maybe you could put them in a desiccator and get the desired results.

GENIUS DUDE - 2020-11-18

Long time no see

Jer Cos - 2020-11-18

I'd expect your bisulfite titration values to be affected by other alkali impurities, and color+turbidity to actually be more accurate for permaganate content with a less eyeball-based measurement (cell phone camera light level sensors come to mind for a hack maybe). Recycling the electrolyte got the cell running, but topping off with potassium carbonate solution might have kept the product cleaner. Fantastic work regardless, it's amazing what can be accomplished with humble but pure materials, a little electricity, and a lot of persistence.

6alecapristrudel - 2020-11-18

Huh, I thought there would be much more MnO2 junk in there.

Scrap Science - 2020-11-18

My thoughts exactly. I did end up filtering the solution after extracting it from the cell and it turned out that there was a gram or so of MnO2 (or something?) that had formed. Still much less than I was expecting though.

Roy Wang - 2020-11-25

@Scrap Science i guess that's mainly from the time when your anode compartment got too acidic / depleted of potassium, before you transfer anything solution back from the cathode

SalamalCamel - 2020-11-18

Should have used the titration station that you made in that old video I reckon

Scrap Science - 2020-11-18

That's very true. If only I had it with me. Might have to do some testing first to see whether permanganate will stain the acrylic though

Paul Frankenstein - 2020-11-18

Can you try the Synthesis of Formalin by electrolysis?

Scrap Science - 2020-11-18

I'd prefer to steer clear of any volatile carcinogens at this stage I'm afraid. But that's definitely an idea for the future, doesn't look too difficult either so hopefully I'll get around to it eventually.

Paul Frankenstein - 2020-11-19

@Scrap Science I think it needs platinum electrodes but not sure at all.
There isn't any video on YouTube so you'd be the first one.

Koukou Zee - 2020-11-18

What if you used a welder with carbon rods to melt your homemade manganese into a smol chunk
And make it 100% homemade permangante

Scrap Science - 2020-11-18

If I were to make a bit more manganese it would definitely be feasible to melt it into a small electrode, but with the quantity I have it would be likely to simply oxidise away. I also don't have a welder at this stage and my furnace can't reach the right temperatures, so my efforts are currently going towards making the homemade manganese into a big chunk from the beginning.

XvAvX - 2020-11-18

Can you use the pure manganese metal for the electrode in a chlorate cell?

Scrap Science - 2020-11-18

That's an interesting idea. Maybe the surface would be oxidised to MnO2 under the chlorate cell conditions and simply run as a usable anode indefinitely. It seems a little too good to be true but definitely something worth investigating at some point.

Pyromaniac Attack - 2020-11-19

Hi there. As someone who's attempted permangenates before I know how tricky the actual extraction is. My suggestion is to pay attention to PH when boiling down your solution. Permangenates break down at a Ph of around 10 back into mangenate, so keeping the ph neutral is quite important as it will rise with the removal of water. Also, permanganic acid is pretty unstable and will break down during the boiling of the soloution.

Scrap Science - 2020-11-19

Thanks for the tip! I probably should have put a lot more effort towards neutralisation when I was trying to crystallise the permanganate. I did do my best to acidify with bicarbonate but didn’t realise how sensitive the pH adjustment actually was.
Next time I’ll be prepared to do it properly.

TeslaFactory - 2020-11-18

What's the power supply you're using? If it's DIY, could you share some links?

Scrap Science - 2020-11-18

I basically just use an old PC power supply hooked up to a dirt cheap buck converter from ebay. I have a video on setting up the PC power supply here:
(Beware, that video is pretty old now and is likely to be pretty bad)
The cheapest buck converter I could find (the one I'm using) was here: http://www.ebay.com.au/itm/192007593319

TeslaFactory - 2020-11-19

@Scrap Science thanks! Good to see I'm not the only one doing electrochemistry down under :)

Colter Denison - 2020-11-20

Hi. I love your videos. I do have an idea for making a possibly better membrane for your experiments. I haven't tried it yet but it should work.
1. Grind some salt (table salt, rock salt, etc) into as fine a powder as possible. The finer the better. (Best to use a ball mill for the finest particles).
2. Take some HDPE plastic from either a milk jug or a shopping bag and melt it in a small pan over a hot plate. Make sure that you use enough plastic to make a thin sheet and that you put the hot plate on a low heat, just enough to melt it.
3. When melted add the salt powder into the plastic and stir it with a spoon or stick until both components are mixed thoroughly.
4. Make sure that you spread out the plastic/salt mixture as thinly as possible. Turn off the hot plate and take the pan off and let the mix cool.
5. Take off the plastic/salt film and then soak it in hot water to dissolve the salt away. Repeat this step several times to ensure that all the salt has been dissolved out of the plastic.
This will make a porous film that will hopefully be better than using a clay pot as a diaphragm since this is thinner, allowing for both more electrical current and ions to flow through. You can probably make it even better if you add a small amount of graphite powder to make it more electrically conductive. I hope this idea helps you with your experiments. Cheers.

Scrap Science - 2020-11-21

I've given this type of setup a go a few times in the past (with different plastics like hot glue or HDPE), and I'm afraid the plastics pretty much invariably coat the salt particles (or anything else I'm trying to encase) in a waterproof film such that the salt can't be dissolved out of the structure.
I dunno, maybe I'm doing something wrong. Do you have any ideas on how the salt particles could be 'exposed' in the structure for proper dissolution?

Colter Denison - 2020-11-21

@Scrap Science Maybe you could try to scrape the surface of both sides of the membrane with some grades of sandpaper, each time do so lightly, this would thin out the membrane further but don't thin it out too much. First with some course grade, then with some fine, and lastly with some ultrafine which you can probably get off the internet. Make sure that you rub each side lightly, especially with the course grades as to not create large holes in the membrane. Then I would wash it in pure water to Also, it might take a bit longer if the membrane is mixed with graphite (since it is a lubricant) but to increase electrical conductivity. I'd give it a shot. If not, then you could also try to thin a piece of clay pot with a sand blaster or something. Just make sure to wash the clay piece out really well to get the dust out of the pores.

SalamalCamel - 2020-11-18

is that a new boost converter?

Scrap Science - 2020-11-18

Nah, same buck converter I've been using for a little while, it probably hasn't shown up all that often in the last few videos though. I upgraded from the stupid carboard box power supply a few months ago.

jaih12 - 2020-11-18

How well does a clay pot work as a separator, compared to other methods, lambskin condoms, gelatin etc?

Edward Science Innovations - 2020-11-18

really good, doesnt react, it holds liquids but allows ions to pass, and no contamination

jaih12 - 2020-11-18

@Edward Science Innovations even over the course of days? I always figured since terracotta is porous, and water molecules can squeak through, it would be similar for other solvents, acids... etc

Scrap Science - 2020-11-18

Yep, a clay pot seems to hold up incredibly well despite the oxidising strength of the permanganate, especially in this non-acidic environment (in acidic solution, it seems the pots are somewhat less inert). Any kind of organic based separators would quickly be destroyed by the permanganate I'd imagine. It does (very slowly) let the solutions seep through the barrier but due to the electrostatic attraction of the ions to their respective electrodes (for example, permanganate is attracted to the anode), this effect is conveniently minimised.
There are other options for a separator too, porous alumina and maybe some kind of fibreglass matting would likely perform even better than a clay pot, but given how cheap the pots are, how large their surface area is and how well they work, I think they're pretty much ideal.