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Organikum
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zincdust
For a new way of hexamine to methylamine conversion I would need some zincdust.
(to be true , the patent is over a hundred year old and I need a lot of zincdust... )
I have unlimited amounts of zincoxide (ZnO2) available so this may be my starting compound. I know that it can be done electrolytically by making the
sulfide by means of conc. H2SO4 what is also the electrolyte.
Al and Pb for cathode and anode, 3,1V to 3,8V cell-voltage and about 300A/squaremeter up to 1000A/squaremeter for current. Addition of gelatine helps
to minimize corrosion at the anode.
Again a industrial process. Can be done on every scale I am sure.
But my question relates to something else: I read that carbide is usable to convert metaloxides to the pure metal. As I have also carbide available I
would be interested how this practically can be done, if it is possible at all with zinc.
Anybody in the know?
How is such a carbide/metaloxide reaction done?
Any howtos, hints......?
ORG
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madscientist
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It would be a fuel/oxidizer reaction, as in:
3ZnO + CaC<sub>2</sub> ----> CaO + 2CO + 3Zn
I weep at the sight of flaming acetic anhydride.
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KABOOOM(pyrojustforfun)
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I think the reaction is something like this:
C6H12N4 + 6H2O => 6CH2O + 4NH3
2CH2O + NH3 => CH3NH2 + HCOOH
HCOOH + NH3 => H2N-C=O(H)
and when heated in HCl solution methylamine chloride crystals remain but other byproducts evaporate away. if u use 2mol formaldehyde and 1 mol
hexamine the method will be very similar to the traditional method that uses 2 mol CH2O per NH3
(I'm confused what zinc is supposed to do)
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Organikum
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In the methylamine synthesis this is going on after hexamine split into formaldehyde and ammoniumchloride:
the formaldehyde is carbonylgroup and reducing agent, good trick but yields are 50% or less by nature of this reaction.
And thats what should happen with zincdust:
C6H12N4 + 4 H2O -- Zn dust--> 4 CH3NH2 + 2 CO2
So says patent DE73812 from 1893 and there is no reason to doubt it as the Leuckard reaction with Zn/HCl is quite common.
Probably a mix of first and second one will occur, but it´s worth a try in my eyes.
But my question was on the carbide reduction of ZnO!
madscientist might you help me on the reaction conditions? What solvent if any needed at all? How would you try this? A hint for a metaloxide
reduction similar would be suffficient, I just don´t like this "surprised surprised" feeling after the fire is out.
ORG 
btw: is "Aethylaldehyd" (old german) acetaldehyde as I guess?
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madscientist
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I would finely powder your ZnO and CaC<sub>2</sub>, mix as intimately as possible, and see if the mixture can be ignited. If it can't
be ignited, try heating over a propane flame; and if that doesn't work, put it in a steel can and toss it in a charcoal fire. One of those
methods has to work.
I weep at the sight of flaming acetic anhydride.
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Organikum
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thanks madscientist. I will try and report the results.
btw, this sounds as it might be worth to try it in a microwave. But first it will be done as advised.
ORG
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Organikum
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carbide or Al
The reduction of ZnO2 with carbide seems to work also it is a quite hot and fast reaction. The problem is the workup. I see no way to get reasonable
clean zinc out of the leftover mess, not to speak of zincdust.
Before I try the electrolytic method as told I will have a look in this I found in another thread here on the board:
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2AlCl3 (aq) + 3Mg (s) -> 2Al (s) + 3MgCl2 (aq)
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I believe that will fail in practice. Al is too reactive to form in aqueous media, either by displacement with more reactive metals or electrolysis.
Note, however, that you can make zinc powder this way, starting with zinc chloride and aluminum "
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wrote Polverone.
Sounds a much more feasible way to me.
Comments welcome.
PS: Just realized this being my 100 post here!
So let it be Sex & Drugs & Rockn´Roll tonight!
(as legal as any possible is understood....)
[Edited on 13-4-2003 by Organikum]
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Organikum
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Al foil is no good source for aluminium....
I tried ZnO2 -> ZnCl2 -> Zn dust, by simple making the zincchloride from zincoxide via HCl and dehalogenation with aluminium.
Polverone has told this working and also added two points:
Point one was, he stated the reaction yould need some Hcl to kick in, the second point was, that the Al-foil caused the Zn not tp precipate as powder
but as parts resembling the used Al foil as it looked.
I didn´t use additional HCl as this seemed to me unsporty. I used the fair and facile MICROWAVE. Worked perfect. Two minutes on full power and it was running almost too fast and hot. (I saw it to late kicking in as
a plasticbag attached as gas and acidcatcher got in the way and hindered my sight).
Recommended. Both. Microwave and plasticbag.
Second:
DON`t USE ALU-FOIL IF YOU WON´T SPOIL YOUR REACTION!!!
I started with Al-sheets I had by hand and everthing worked perfect. After these had been spent I used Al-foil and all was shit at once. There is a
certain small but annoying amount of plastic on the foil, making this stick together, hindering the rection to breath and more shit.
NO PROBLEMS WITH SHEETS. The foil - catastrophe.
A picture of the mess after foil:
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Polverone
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Microwaves, huzzah!
I am glad that you were able to get the reaction going in the microwave. I'm sorry that the use of aluminum foil didn't work for you... but
mine did not have plastic in it.
Still, I am curious if you would elaborate on "everything worked perfect." You obtained reasonable quantities of usable, finely divided
zinc? If so, that is good to hear! I had assumed that larger chunks of aluminum wouldn't work as well as foil, but now I may have to try sheets
myself.
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Organikum
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I bet every Al foil with a a shiny surface is kind of polymere bonded/protected. How would it come that it doesn´t oxidise on one side?
And it is as you described - the foils structure survives the dissolving of the Al - this must be something from the shadowworld (shivver...) or some
coating/polymere.
The Al sheet dissolved flawless, no problems. With the foil it got messy as the gasbubbels are hindered to escape and the mess goes up like bread in
the oven.
Zincoxide was dissolved in HCl until no more gas evolved when more zincoxide was added and solvation took only place if heated. (over several days,
just en passant....)
To this solution of zincchloride first Al sheet was added and later foil as described.
Kickstart by microwave - without microwave irridation there was no reaction visible also not under heating on a hotplate for some minutes.
There is a good amount of gas evolved when the rection kicks in - the use of a plasticbag for holding this back was a very good idea - I would
recommend this to everyone - makes sense is easy and offers significant advantages.
New zincchloride is in "en passant" position - in the next days this will get retried with proper measurement and stochiometric
calculations.
This was just a proof of principle (microwave kickstarting and Al-sheet). Instead of sheet Al wire will be used (electrocablewire, high purity and in
endless amounts available for me ), there is no doubt for me that this will
work even better as sheets.
Considerations:
The dust is of such a fine form, that it might get difficult to separate it by plain settlement, baking together and the carryover of zincchloride
over all a fucking mess this might get. I look now for a second solvent, heavier as water, inert to the reaction inmiscible with water and
zincchloride and aluminiumchloride. By counterstreaming the (post)reactionmix through this solvent the zincdust should be washed out and be
collectable at the bottom in a clean and usable form.
Comments?
addon:
the first picture is beautiful, a piece of art, isn´t it?
[Edited on 1-5-2003 by Organikum]
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Polverone
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Oh, that first picture is indeed lovely. As to the zinc isolation, the idea of using a heavier solvent (pick your favorite halogenated liquid?) to
separate the metal dust from the aqueous bits sounds like a good possibility. One thing I noticed when I did my experimentation, those months ago: the
liquid can become very thick and sticky with ZnCl2/AlCl3 as water evaporates, and it was difficult to remove from the zinc. Did you experience any of
these problems?
I don't know exactly why aluminum foil retains its shape as it is replaced with zinc, while larger pieces of aluminum do not. I think we can
safely assume that law enforcement agencies or water sprites are causing it.
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Organikum
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Precipated Zn as dust and sedimented
A pic of the sedimented (it is not very hard baken together, only slight modifications will be necessary)
More is very slowly in sedimentation now, but mixed with tiny foil residues. I wanna guess this opens the road to easy Zn catalyzed reactions.
At least for me.
Gentlemen, start your engines....
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Polverone
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very nice
My zinc dust supply will probably last me for years, but your example is inspiring. I now want to see just what sort of nice zinc dust I can make at
home. Fine metallic powders are equally fun for the organic chemist and pyromaniac alike.
Which reminds me, now that I think of it: one of the low points of my earlier experimentation was when I set a pyrex dish with the damp porous zinc
foil on the stove to dry, only to ignore it too long and find a small but merry metal fire when I returned. And wouldn't you know that the dish
broke when I threw it in the sink... I wouldn't normally work in a food preparation area but this was while at parents' home on a weekend.
I find the characteristic appearance of burning zinc to be lovely, one of the nicest of burning metals, but I hope that you have no occasion to
encounter it by accident.
I also wish you the best of luck in your mysterious zinc-powder-needing experiments.
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a_bab
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I also got a nasy burn when I lit a very thin Zn foil. It catches fire just like magnesium; the issue is that if the foil is too thick it'll melt
rather than catch fire. The flame is violet in colour (very nice, almost like K but more shiny)
Zn dust can also be obtained from Zn lumps, if you heat these lumps at about 200 degrees and then smash with a hammer. This will turn the lumps into
dust as Zn breaks just like glass at 200 degrees C.
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Organikum
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the lumps are new
to me at least.
Thanks a_bab!
I didn´t wanted to dry the zinc dust anyways as I have the feeling that drying would make it loose activity. I want to store the dust in liquid
(degassed) until it gets used. Makes in my imagination everything easier - at least it makes it easier to imagine how to proceed furtheron for me.....
Yep, dust and explosion are relatives. I saw once the result of a flourdust explosion in a smaller mill. Not bad.
And of course the famous selfsinking first overheavy warships with full armouring, which tended to ignite the dust in the coal-bunkers with even more
impressive results....
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a_bab
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You're welcome Organikum
Another way to get Zn dust is to boil Zn and to condense the vapours. That's the industrial process actually. It shouldn't be that hard to
set up a device assuming that you really need it
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Organikum
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I doubt that you get dust by condensing zinc - grinding or milling will still be necessary I guess, whereby your excellent information on the
brittleness of Zn at 200°C calls for milling at this temperature for easy dust production.
Dust in one step from the molten state can be achieved by dropping the melt through the center of a sonotrode (ultrasound) in form of a ring and in a
water (or other liquid) bassin below. Works for all metals.
Ultrasound is as fascinating as powerful sonotrodes are expensive......
addon on Al-foil:
Reynolds foil is made of 98,5% Al alloy I found out, which contains also Fe and Si. Al sheet as used by me is 99,5% Al after specification. I still
postulate that Al wire from electrocables will show as superior. 99,99% Al, what could one demand more?
[Edited on 2-5-2003 by Organikum]
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Organikum
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I stopped my approaches on producing zincdust this way after I stumbled over some Zn primer for rust protection which contains about 70% zincdust
whats quite easy to wash out with xylene. And the stuff is cheap.
Lazyness is a hard to beat.
I had some tries with the zinc produced this way for the methylamine mentioned at start of the thread. It worked, not perfect but it´s hard to say if
the zinc is to blame for - now with the bought zinc and some experience the process works like a charm. Keeping the reaction cold and time - adding
the zincdust slowly - thats the key the rest is pipifax. 24 to 36 hours - to build an automatic "zincdustdispenser" is favorable
I meanwhile read something on the properties of zinc and aluminium which irrates me. It was told Zn is nobler under basic conditions but Al is nobler
under acidic ones. Anyone knows more on this? And how did I get Zn this way - it was Zn and not Al I am sure. (mostly Zn at least)
For the fun I will try the methylamine reaction with aluminiumsheet/granules instead of zincdust.
We will see.
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Marvin
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I have doubts about zinc being brittle at elevated temperatures. This would be an unusual metal if it did. A quick check of an online reference
about zinc states thats its brittle at room temp, but malliable at 100-150C. This is more inline with what we would expect. Maybe a_bab your
reference is confusing 200C with -200C?
I'm not entirly sure what more or less nobel means, but if we assume its just about lack of reactivity, then that is explained mainly by the
oxides. Both oxides are amphoteric, but zinc oxide dissolves quickly in acid but rather slowly in alkali, and aluminium oxide is the oppasite. This
is mainly what affects the rate at which the metals dissolve in acid/base.
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Organikum
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MERCK index
It is in the MERCK: Zinc becomes malleable at 100°-150°C and brittle and pulverizable at 210°C.
Perhaps a confusion with tin? This is named to be brittle at 200°C but malleable and pulverizable with ease at room temperature. It crumbles to grey
amorphous powder at -40°C.
This correlates with my all-day experience very well.
I will look for whereI read this on the Al and Zn properties and post it more exactly. Must be on my harddisk somewhere.......
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Marvin
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No confusion I think, I'm simply wrong.
Ive checked Mellor and it states that zinc can easily be crushed in an iron pestle/mortar at 205C. It goes on to say this is due to a change in
allotropic state at 170C. Its changes in allotropic state that explain the odd behavior of tin, but we expect this in tin.
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Organikum
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ehem
I was probably quite stupid as it seems zincdust can be easily made from ZnO by converting the ZnO to zincsulfate by H2SO4 (battery acid) and then
converting the sulfate to the metal by aluminium foil and some NaCl (table salt) added.
I will try and post some pictures soon.
ORG
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KABOOOM(pyrojustforfun)
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what does the NaCl do here???
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Organikum
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nothing
It doesnt work as it seems.
I hoped it would work similar to.
CuSO4 + Al - NaCl -> AlSO4 + Cu
which works fine.
But I was wrong.
ORG
(NaCl because of (CuCl4) 2-)
[Edited on 13-1-2004 by Organikum]
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theh0ser
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zinc
where can i get zinc without going to a supplier
-------------------------------------
READ THE THREAD FOR GOD'S SAKE!
[Edited on 15-2-2004 by vulture]
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