Author Topic: manganese (III) acetate  (Read 2045 times)

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paccman

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manganese (III) acetate
« on: October 31, 2004, 02:47:00 AM »
swip was reading the below, but swip is not verry clear on the process, can anyone clarify or have a clear wirte-up.

how much h2o?
how much hcl?
what is (sonl.)?


15 g KMnO4 was dissolved in some hot water and combined w/a soln of 15 g hexamine. Nothing happened. Then conc HCl was added in portions w/swirling until mixtr acidic. As he did it, the mxtr gradually turned completely clear and the stench of formaldehyde became almost unbearable . Then SWIM put the soln in a 5 liter jar and mixed it w/a molar excess of saturated NaHCO3 (you can calculate it if you want - SWIM just took a large xcess). White precipitate (MnCO3) forms. The jar was filled w/water to wash it. DO NOT use NaOH for precip'ing manganese - Mn(OH)2 instantly oxidizes when exposed to air, and the carbonate is pretty stable.

When all settled, the water was decanted into another jar (to collect the still remaining suspended MnCO3 later) and the precip't washed in the same manner once again, MnCO3 in the other jar washed later too. Then all combined, water decanted off, precip't vac. filtered - do not dry it - there's no need for that, and it will oxidize somewhat during drying. Just scrape it off the filter and dump into some GAA. Now, guess what, there was no fizzling and bubbling at this stage as SWIM expected, in fact, to dissolve all the MnCO3 it took a 2 hour reflux. At this stage the soln was a pleasant pink color, just as it should have been.

The GAA was boiled off overnight at 130°C in an oil bath and when SWIM woke up he found that the bottom of the flask was covered w/some white (not pink) crystals - well, he thought, that must be unhydrous Mn(OAc)2 (the pink stuff is a tetrahydrate) - and so it turned out to be. SWIM dosn't remember the exact weight (21 g?) but the yield was quantative.

Now SWIM went on to dissolving his salt in GAA, 250 ml (SWIM thought you'd have to 1st evap. GAA and then dissolve in it again as the former one has water in it - but he was wrong as you'll see. Well, he needed to weigh it anyway. Just skip this evap'n/dissolution step, it's probably not needed) - the shit doesn't dissolve! even w/reflux! Probably, SWIM thought, the unhydrous stuff doesn't, so he added a theoretical amount of water, well, a little more in fact, about 7 ml to the mxtr and w/some boiling most of it went in the soln, some was still left at the bottom - it was OK, as it turned.

To this boiling soln SWIM added about 5,4 g (~1/4 molar equivalent) of KMnO4, in, say, 6 portions. During and after each addition the mixture was vigorously stirred with a glass rod. The KMnO4 must be prior to that ground as fine as possible - it's not hard at all. The mixture turned dark and opaque. Boiling was continued for some 10 min, then the flask put into the fridge (16°C) and 3 ml water added to it to induce crystallization. The walls of the flask were periodically furiously scratched (on the inside) with a glass rod and after like 10 hours - voila! - a heavy crop of dark brown, as they should be, crystals precipitated. (If it doesn't, you can add 3 ml more water to it and w/some scratching it'll happen in an hour).

The mixture was filtered, the mother liquor still very dark (put 3 ml water into it and let stand for a week - all of your prouct will crystallize and the liquor will turn colorless, this time the crystals will be not dark brown, but of rust/cinnamon powder color, just like the dry stuff), crystals sucked as dry as possible and dried for ~3 days in a dessiccator over CaO. Dry Mn(AcO)3 is a very, very fine rust colored powder, it's unbelieveable how much it increases in volume comparing to the initial KMnO4! Still the weight is consistent - SWIM got about 22 g from the 1st crop, and the 2nd one is still in the flask, probably will be ~5-7 g - the original article states the yield of 85%, fits w/SWIM's result perfectly.

bio

  • Guest
manganese (III) acetate
« Reply #1 on: October 31, 2004, 08:07:00 PM »
The carbonate is really easier to find than the permanganate and also way cheaper. So just start from carbonate or dioxide. I found it was best to simply boil the carbonate with acetic acid until saturated, then add fresh and continue until most all was converted to the Mn2.

 See the many patents listed in the Mn3 thread. US4356317 shows the recycling insitu of the Mn2 to Mn3AcOH. It is also very easy to make the 3 from the 2 electroliticly with only more of the acid which is also used as the solvent.

paccman

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dimethylbenzene (xylene) substitute for benzene
« Reply #2 on: November 01, 2004, 04:24:00 AM »
in the above, swip wonders if dimethylbenzene can be substituted for benzene. benzene where swip resides is extremely hard to acquire without arising suspiscion. swip also wonders if anything eles and be used in place of benzene.. thnx

Rhodium

  • Guest
Results of benzene substitution
« Reply #3 on: November 01, 2004, 10:30:00 AM »

paccman

  • Guest
if swip substituted dimethylbenzene (xylene)...
« Reply #4 on: November 10, 2004, 02:42:00 AM »
if swip substituted dimethylbenzene (xylene) for benzene,what will be the end product? would that product work in the synth.


Rhodium

  • Guest
You would get (inactive) dimethylamphetamine.
« Reply #5 on: November 10, 2004, 10:53:00 AM »
You would get (inactive) dimethylamphetamine.


paccman

  • Guest
so what is (inactive) dimethylamphetamine?
« Reply #6 on: November 11, 2004, 01:00:00 AM »