Sciencemadness Discussion Board

Manganese Acetate...

evil_lurker - 4-8-2005 at 16:33

Ok I think I'm right on this, but I wanna make sure before I order my reagants.

Mn2+ (bare metal) will combine directly with glacial acetic acid to form MnAoc (II) correct?

What would the dioxide do?

Nerro - 4-8-2005 at 16:41

Do you have ANY idea what you're talking about?

evil_lurker - 4-8-2005 at 16:51

Quote:
Originally posted by Nerro
Do you have ANY idea what you're talking about?


I think I do, I'm not a chemistry expert and I have had no formal training, never even took high school chemistry.

Yes I know very stupid question.

I'm tihnking that the manganese would readily combine with the glacial acetic acid to form the desired product.

But from what I have read, some metals do not react very well with some acids, therefore the reason behind posting this question.

12AX7 - 4-8-2005 at 18:08

I'd think 20% or so in water would be better, the salt is probably hydrated (tetrahydrate for diacetate), so you'd just get junk instead of a nice solution, being that it wants to be hydrated. And/or it may not be too soluble in GAA (I have no idea how it fares as a solvent) anhydrous like that. And metal will want to release hydrogen, which may or may not be very good with GAA, being a weaker acid than HCl or H2SO4. It should dissolve pretty well though, being up there near zinc in reactivity. MnO2 will probably oxidize things before dissolving, at a glance I only saw Mn(2) and (3) acetate listed on Google. Might work with a reducing agent to distract its fury though.

If you DO have Mn metal on hand, I'll take it! Could use it for manganese aluminum and copper alloys, as well as cast iron and steel when I get to melting them. As I understand it, metal (or at least pure metal, not speigleisen) isn't common to come by.

Tim

evil_lurker - 4-8-2005 at 19:27

I noticed that the pyro site skylighter does have the metal powder for use as a burn rate modifier. Plus, its only a lil over $10 a pound US.

Anyhoos after some research and thinking, your right, Mn2+ does decompose water slowly to the hydroxide which should react with the Acetic Acid forming the Acetate salt, or so the theory goes. At least thats what Vinegar does to Sodium Hydroxide.

AFAIK, the salt is soluble in GAA.

bio2 - 4-8-2005 at 23:02

Mn elemental must be pretty pricey compared to the salts. Also might take a year to dissolve the shit! Also water is not wanted with the acetate as it's a real bitch to dry.

Best is to reflux GAA with the carbonate till saturated then crystallize and repeat until it's all dissolved.

MnO2 works also and the chloride can easily be converted if you have this readily available.

praseodym - 4-8-2005 at 23:34

Quote:
Originally posted by bio2
Also water is not wanted with the acetate as it's a real bitch to dry.

Cant the acetate be dried by CaO or K2CO3?

bio2 - 5-8-2005 at 20:09

Sure; it can be dried over many things in a vacuum dessicator. Depends on how long you want to wait to remove the water.

Manganese sulfate

chloric1 - 6-8-2005 at 16:36

I have seen Manganese sulfate sold as a gardening micronutrient for about $10 for 5 pounds. Would need purification though. This in combination with ammonium sulfate you could isolate electrolytic manganese. If you use a cathode of aluminum alloy of the 5000 series the manganese should come off easily.

Jome - 6-8-2005 at 17:15

Dissolve the Mn in hydrochloric acid, add Na2CO3, wash the manganese carbonate, add acetic acid to manganese carbonate!

praseodym - 7-8-2005 at 04:56

Well, it works... But wouldnt this reaction be rather slow?

Tsjerk - 7-8-2005 at 06:02

The reaction between the manganese carbonate and glacial acid is pretty slow indeed. You'll have to dissolve it in GAA (or another solvent), use the hydrated manganese carbonate, dehydrated doesn't dissolve (At least in GAA it doesn't, don't know about other solvents).
Then just reflux it at about 60 degrees.

12AX7 - 7-8-2005 at 07:01

Think double decomposition would be at all valuable, like the copper acetate method? CaAc2 + MnSO4 = CaSO4 + MnAc2.

Tim

(Humm, somehow I doubt the "actinide" anion exists. But you know what I mean ;) )

evil_lurker - 7-8-2005 at 19:43

I might just take some KMnO4 and react it with hexamine and proceed from there.

Found a source for it, that being the industrial supply company Grainger.

They sell 5 pounds of pure KMnO4 for around $35.:D

Shop around

chloric1 - 7-8-2005 at 19:48

My local hardware sells the same stuff for $17 for 5 pounds.

bio2 - 7-8-2005 at 21:37

.......I might just take some KMnO4 and react it with hexamine and proceed from there. .......

This is a pain in the ass compared to picking up the carbonate at the pottery supply and a jug of GAA. is the only thing else you need.

The Mn2 can be oxidized to the Mn3 at a carbon anode in GAA at 50-70deg.

gsd - 18-8-2005 at 20:38

Manganese Acetate is actually Manganese (II) Acetate - Tetrahydrate.
M.W. = 245
It contains 22.4 % Mn.

1) If you have access to Manganese Metal then you can very easily prepare it in a pure solution form my reaction of Metal with dilute AA.

Take 150 gm of metal add about 500 gm water and then slowly add 360 gm GAA with constant stirring. External heating is not required, the reaction is quite vigorous and exothermic.

In the end it is important to keep the Acid in slight excess.

Also the reaction MUST be conducted in open or under hood as large volume of Hydrogen gas is evolved.

After reaction is over just filter the solution to clear pink filtrate and evaporate the water to get nice pink crystals of Manganese Acetate.

2) AA will not react with MnO2 (In fact even H2SO4 also does not react with MnO2 directly) You will have to reduce the MnO2 first to MnO by igniting it with a reducing agent such as heavy oil. This process requires bit of skill to carry out on a small scale and resultant solution obtained after reaction of MnO with dilute AA also needs lot of work-up in order to get pure MA. (as Mn02 in ore form contains lot of impurities which must be removed)

3) If either Manganese Carbonate or Manganese Hydroxide is available then MA can be easily prepared by reacting it with dilute AA ( you will need good stirring and heating as well) and subsequent filtration - evaporation - crystallization of solution

evil_lurker - 18-8-2005 at 22:47

The other day I found a pottery supplier where I can get 10 pounds of the carbonate for less than $20. :D

Anyone got a suggestion for the AA?

I'd like to keep my costs on that below $15 per liter.

The_Davster - 18-8-2005 at 23:12

Vinigar?

Some dyeing suppliers sell 56% AA

Photography suppliers sell anywhere from 80 to 100% acetic acid.

[Edited on 19-8-2005 by rogue chemist]

Carbonate -> acetate replacement

BenZeen - 17-3-2010 at 02:47

Hi everyone
Ok, simple question, please dont flame me.
When converting manganese carbonate into manganese acetate is it essential to use glacial acetic acid, or will acetic acid perform the anion replacement reaction equally well?
thanks for any help :)

woelen - 17-3-2010 at 02:52

Aqueous acetic acid will do the job as well (probably even better), but you need to heat the liquid to get all of the MnCO3 dissolved in the aqueous solution of acetic acid. You also probably need excess acetic acid if you really want to have all MnCO3 converted to Mn(CH3COO)2. If you use exactly balanced amounts of MnCO3 and acetic acid, then you'll see that the last part of the reaction proceeds VERY VERY slowly, hence the need to use excess acid. What remains is a solution of Mn(CH3COO)2 in dilute acetic acid.

BenZeen - 17-3-2010 at 02:57

thanks Woelen

bbartlog - 17-3-2010 at 07:34

In fact, based on comments in the glacial acetic acid thread, it's entirely possible that GAA would *not* work well at all. One of the proposed tests for dryness is a lack of reaction when calcium carbonate (or was it some other carbonate?) is put in the acid. The acid being a weak one doesn't dissociate much, and even less when little water is present. I don't think you'd want to go higher than 70%.

peach - 6-12-2011 at 18:35

Manganese (II) sulphate (probably the monohydrate), stir bar, beaker
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@Waaaater, water of life, jesus gives us the water of life!@
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Sodium bicarbonate, use an excess
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Sulphate has dissolved
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Sulphate + bicarbonate --> foam
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Wait for the effervescing / fizzing / foaming to stop and then allow it to stir a while longer. Leave it for an hour or two (or overnight) if you want to be sure you've got all the sulphate converted, or give it a warm too. Manganese (II) carbonate is precipitated as an insoluble solid. Both sodium carbonate, bicarbonate and the sulphate are water soluble, so the solid Manganese (II) carbonate can easily come off with a coffee paper. It is a very faint pink. Your filtrate should be colourless. If you're worried about having not converted all of the sulphate, try adding some more bicarbonate to the filtrate and see if you get anymore manganese carbonate out. This would be more of a concern if you'd had to put a lot of effort in getting the manganese cleaned up from battery paste or pottery grade.
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Allow it to drain until it's no longer dripping, then dump it into a flask. If you have well precipitated the carbonate, you can calculate the rough amount of carbonate you have here from the amount of sulphate that went in. You now cover it with a slight excess of acetic. I'm using 98%.

This conversion could also be done in a beaker. The reflux temperature is somewhere just over 100C. As soon as it starts getting close, it'll be fizzing away. Leave it to sit for an hour near reflux and the opacity, caused by the carbonate floating around in there, will disappear; you'll end up with a transparent (slightly slutty) pink solution. Again, leave it to go a while longer to ensure it's all converted. Stirring isn't necessary.

I started with about 30g of sulphate and that is a 100ml flask, and (near / at reflux) it was foaming it's way up the condenser. Use a 250ml or leave it below the reflux for longer (less foam produced when it's not boiling).
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Hot hot hot!!!
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Put it under the cold tap for two minutes and the entire contents solidified. The tap is at about 10C, which is below the MP for the acetic.
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I gave it a warm under the hot tap until almost all of it had gone back to a liquid, then left it to cool to RT naturally.
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Lots of solid back again.
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Some of the remaining acetic / moisture.
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I decided to drain that off, to be more sure of the moisture content / mass etc. Bubble gum pink has been reobtained.
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Leaving the stir bar in there proved useful upon removing the solid. Should have poured this out into a dish really.
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Sucked dry, candy floss pink. A soft mush.
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Back in the flask, add some more acetic.
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Weighing out a corresponding amount of permanganate.
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The 2 acetate beginning to melt into the acetic, which is coming close to it's reflux temperature
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Great purple! Adding the permanganate over 20 mins.
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The acetate immediately begins turning a dark brown.
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Too late matey! Train's left the platform!
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Ten minutes in....
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The flask looks like this..., heating continues for another 20 minutes after the addition.
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@Waaaatar, water of@ RECRYSTALLIZATION! Poured into the flask, given a shake, then...
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Awwww cumon! This is the one that should have stayed in the flask. The 2 acetate was all lumpy solid stuck in there. This is more like dust. The 2 acetate should be a dish or beaker when it cools, this.... leave it in a beaker or flask so it can have a swirl on the way out.
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COMMENCE AGAIN WITH THE SUCKING!
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Filtrate is colourless, which is nice.
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I just cleaned that funnel... coffee filter next time me thinks.
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Left to sit on top of the radiator (45C) for 24h. Very, very dark brown Manganese (III) acetate.
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Formulae

MnSO4 + NaHCo3 = MnCo3 + NaHSo4

Mn3O4 + 2CH3COOH → Mn(CH3COO)2 + Mn2O3 + H2O

4 Mn(OAc)2 + 5 HOAc + KMnO4 → 4 Mn(OAc)3 + KOAc + MnO2

Other manganese sources

You can start from the chloride if you like, or the nitrate.

Something interesting about the nitrate is that it can also exist as the tetrahydrate, is well soluble in water, melts at 37C and boils at, guess what! 100C ;)

Can I steal your photos for my own forum / website / christmas cards?

Steal away!

Just don't go claiming copyright on them or using them in your science fair project as your own.

[Edited on 7-12-2011 by peach]

[Edited on 4-18-2015 by Polverone]

ldanielrosa - 8-12-2011 at 02:48

Those pictures are beautiful. You're my hero, Peach- when I grow up I wanna be just like you!

That bit about the BP of Mn(NO3)2 got by me the first two times I tried to synthesize the stuff (by metathesis), so I only got manganese oxide precipitate forming in nitrate solution when I heated it to accelerate evaporation.

On the upside, you give my new hope that my attempt at Mn (II) acetate which I haven't yet dumped may be worth more effort.

mnso4 industrial route

learner1112 - 24-1-2015 at 22:53

i am trying to figure out an economical industrial route of processing mnso4 from natural ore. essentially mno2. the first process is to burn sulphur and inject the so2 formed into the crushed ore and water solution. the slurry thus obtained is kept at ph4-4.5 by adding lime. after the reaction the slurry is filtered and the liquid which is pink in colour is obtained. now the problem is how to seperate the mnso4 present in the solution. can anyone guide me, as when i try to heat the solution its ph goes down and it becomes acidic with evolution of so2 gas and probably the mnso4 is converted baqck to mno2.

Manganese Carbonate

acetatecorp - 21-4-2015 at 16:06

Thanks for the detailed procedure Peach, I followed your instructions and got the same fabulous result. Just one question about the Manganese carbonate:

It works great via the double displacement of the Manganese Sulphate and the Sodium Bicarbonate, but when done with Manganese Sulphate + Sodium Carbonate I get a fluffy brown precipitate that dries to a light brown powder with a carbonate feel. I've researched and looked up many photos of Manganese carbonate for sale and many of these are in fact brown. On other parts of the net the colour varies from white to light pink.

I've gone over the reaction equations also and I'm stumped as to why I get two very different results. Also, when making the acetate (II) from this brown powder & AA, the reaction does not work and produces a small amount of dark brown precipitate.

acetatecorp - 21-4-2015 at 16:10

Sorry, this is my first post on here and my question probably wasnt clear:

Does anyone know why there is such a huge discrepancy between trying to make the carbonate from Sodium Carboante VS. Sodium Bicarbonate?

blogfast25 - 21-4-2015 at 16:54

Quote: Originally posted by acetatecorp  
Sorry, this is my first post on here and my question probably wasnt clear:

Does anyone know why there is such a huge discrepancy between trying to make the carbonate from Sodium Carboante VS. Sodium Bicarbonate?


There should be no discrepancy at all, assuming similar purities of the sodium carbonate and bicarbonate. Using carbonate will cause no CO<sub>2</sub> fizz, of course.

Technical grade MnCO<sub>3</sub> varies in colour from white with a pink tinge (very pure) to beige to beige/brown (quite impure). The contamination is almost always due to iron(III) oxide. Mn and Fe are often found together and are not so easy to separate. They will precipitate together using carbonate/bicarbonate, the iron as Fe(OH)<sub>3</sub>.

[Edited on 22-4-2015 by blogfast25]

UC235 - 21-4-2015 at 17:29

On leaving some freshly prepared, moist manganese carbonate outside a few years ago it became a light brown from a pink-tinged white. I assumed that this was oxidation to MnO2, so the brown color of a commercial sample may not be entirely due to iron contamination.

acetatecorp - 21-4-2015 at 22:01

Thanks @blogfast25. I used cheap washing soda so probably very impure. I'll try getting AR grade sodium carbonate and test again or dehydrate some baking soda.

blogfast25 - 22-4-2015 at 08:32

Quote: Originally posted by UC235  
On leaving some freshly prepared, moist manganese carbonate outside a few years ago it became a light brown from a pink-tinged white. I assumed that this was oxidation to MnO2, so the brown color of a commercial sample may not be entirely due to iron contamination.


The samples that weren't very white that I've analysed all tested positive for Fe(III).

Of course moisture is a vector for air oxygen, so some oxidation to MnO2 is a possibility. Mn(II) carbonate has a general 'reputation' for being stable though.

Quote: Originally posted by acetatecorp  
Thanks @blogfast25. I used cheap washing soda so probably very impure. I'll try getting AR grade sodium carbonate and test again or dehydrate some baking soda.


Or make a hot, saturated washing soda solution, hot filter carefully (sometimes it contains a bit of anti-caking MgO) and allow filtrate to cool and chill. Collect quite pure Na2CO3.10H2O. Repeat for super purity, if needed. The decahydrate isn't very stable though (loses water) and for stoichiometric work it's best dehydrated first.

Baking soda sometimes goes brown on heating because of rice powder as anti-caking agent. It's a test of purity: if it browns on heating it's not very pure.

[Edited on 22-4-2015 by blogfast25]