MAA Electro Oxidation Cells

MiNdBaBY · Sat Sep 10, 2005 7:33 am

MiNd has decided to share and post some detail notes on the electro oxidation cell topic as no one else really has to MiNds knowledge. This is NOT a detailed writeup on how to construct one of these cells, but rather a touch on some important key factors of such. As usual, MiNd really doesn't care nor seeks any input on such, Mind is just choosing to share some of his personal research as he knows it will be of great value to the few whom choose to use it.

As well, Mind has spent maybe one hour in the past month on the forums, and that pattern will not change from here on out, so please do not get too upset if any pm's go unawnsered for weeks or months..

here is a cut & paste of minds' maa research notes as of lately, along with two pics of the cell MiNd references in the typing. The manganese was high dollar LR grade (500g costing $40), while the ammonium sulfate was OTC as a garden chemical costing $5 for a 20lb bag, and the H2SO4 being lab tech grade costing $20 per gallon.

Research notes on electro oxidation cell (file: maa research.txt)

Cell consists of an Ammonium Sulfate and Manganese Sulfate
Take a predetermined amount of Manganese Sulfate (i.e. 500g) and multiple that by .46% for the amount of ammonium sulfate needed.

For 500g of Manganese you will use 230g of Ammonium sulfate.

finely grind/powderize both reagents, and place into a glass or poly beaker or bucket.

Starting from tech grade sulfuric acid (tech grade is 66% purity),

add enough sulfuric to dissolve and cover the reagents, then using a computer power supply for the +12vdc supply, attach a digital amp meter in line.

You'll notice little if any current being drawn by the cell as a result of too high of a acidity content. Pour in distilled water and stir until the current draw goes up to 9 amps, you'll also notice heavy bubbling and red MAA at the positive electrode.

Myself, in my experimental research started a new cell, with a half kg of Manganese and a quater kg of Ammonium, in an appx 3liter beaker inside of a pyrex glass bowl (incase of breakage). After all reagents and liquids added, the beaker was only just past HALF FULL with the two Lead based electrodes inserted.

This new cell, was powered by two computer power supplies, in parrallel, providing a total of appx 20 amps to the cell. The cell was considerably exothermic with extreme heat being produced besides lots of 'bubbling'. The temperature taken after 2 hours of cell operation was 125C before one power supply was turned off in order to reduce the heat of the rxn as in my opinion it was getting out of hand, with regards to the heat being generated..

As well, the glass beaker, actually being an otc pickle jar, placed inside a Pyrex glass bowl in case the jar broke, the bowl also providing a means of a cooling bath if ever necessary. But the glass beaker had not previously been tested with regards to it's temperature capability's. (In the case of acetylaldehyde production, cooling bath is necessary)

So ultimately, it is my opinion that 20amps not be exceeded per one kg total of reagents. And utilizing upto 20amps, very inexpensively provided via two computer power supplies, will fully generate or regenerate the electro based +3 state managanese oxidant compound within 3-4 hours max, very very nice..

Addendum: During the 30-45mins while I was typing this, after which, I went back to check on the cell which was only being supplied by one power supply, I found the cell completely generated and the power supply shut off. What this means is that when the cell is finished regenerating it will short out the power supply and no longer draw current. With computer power supplys which are electronic switching based, they will short circuit and auto shut off to prevent damage to the supply. The temp was taken again at this point, and measured at 115C.

It should be noted that if you are using the cell for toluene to benzaldehyde production, that Toluenes bp at appx 105-109C (somewhere around there off the top of my head), that the cell will reach a temp (with 20amps current) in which the toluene will reach its BP and boil off should there remain any toluene, assuming you use tolly for extraction of the Benzaldehyde which is highly suggested, as any excess will only result in additional benzaldehyde being produced as well as any excess of toluene remaining will easily be boiled off, toluene is the preferential solvent for benzaldehyde extraction.

Additionally, I also theorize that this oxidant would produce methcathinone from pseudo(ephedrine), but this theory has yet to be tested as well as my theory that this compound will bond benzene to acetone or similar benzene based rxn in order to produce p2p, again yet to be tried first hand by MiNd.

This whole continuing project produces an interesting question in my mind, and that is whether or not currently exists an electro based regenerable reduction compound/cell? The implications of such need not be mentioned, but would be spectacular.

MiNdBaBY · Sat Sep 10, 2005 8:16 am

P.S.

MiNd forgot to mention/note that with such high temps, the h2o/water portion of the cell was boiling away which resulted in the cell's acidity level only increasing. This is bad, and though the h2o is easily replaced, it's bad form to have such boiling away!

So if one chooses like MiNd to push it to the envelope, in regards to the amperage (current) supplied to the cell, one will either need to provide a cooling bath in order to prevent/decrease the boiling of the cell's h2o content, or reduce the current flow from the 20 amp envelope pushed by MiNd to a level at which does not produce temps in excess of 95C in order to avoid boiling off any h2o content of the cell, otherwise plan on replacing the cells h2o content after each run, which realistically isn't much of an issue.. Essentially in addition to extracting your end (oxidized) product you also plan on replacing the cells h2o, big whoopdy doo..

bio · Working Bee

........this compound will bond benzene to acetone or similar benzene based rxn in order to produce p2p, again yet to be tried first hand by MiNd.............

Mn3Acetate will do this and can be made and regenerated insitu (the cell). Also only about 1/20 of the oxidant is needed initially due to the continuos regen. There are patents on this.

For cooling try a piece of lead pipe and circulate water though it or just hang an inert cooling coil in the cell. This will work much better than a bath. Also fit a reflux condensor if you want to run hot.

MiNdBaBY · Sun Sep 11, 2005 3:49 am

bio:

Excellent tips on cooling, one of MiNds previous and relatively easy methods was take glass tubing, heat with a torch, and wrap/coil it around a wooden dowel, creating a coil of glass tubing which is run a continuous supply of cool (tap) water, but utilizing this method allows a coil to be custom made and sized to the particular reaction vessel.

In particular to these electro cells, MiNd regularly uses an extremely large cell which is a 3gal (or 5gal) HDPE bucket, with holes drilled in the side which allows for thread rod to be inserted thru and nut's attached holding the electrodes on the inside of the bucket, while nuts allow for attachment of the 'wire' on the exterior of the bucket. These poly vessels work well, but in this particular case, MiNd was curious as to curent density's and just how much it could be pushed.

MiNd had previously showed pictures of such, including the use of overhead stirring for these rxns.

On the topic of the acetate, which is pretty spendy and less common than the reagents for production of MAA, provides for an oxidant alternative [MAA] to the Acetate agent.

As for cooling, ultimately, the cooling of an MAA cell isn't necessary or an issue with a small current flow. But MiNd was trying to 'speed up' the rxn times from his overnight (appx one day) rxn rate to date. MiNd did succeed in such, entirely regenerating a 3/4kg cell in under 3 hours (was not precisely timed), which is pretty impressive, especially from cheap and readily available power supply's.

More realistically, it'd probably be wiser (for most) to just use less current and be content with a 12-24 hour regeneration period, which is well within reason.

One of these cells in the 3gal PE vessel, easily produces a half kg of product a day.

MiNd will mention Ethanal, and that the production of such, will require cell cooling as an necessity, unless you wanna lose your precious ethanal.

In reference to bio's suggestion of attaching a reflux condensor, this in theory is correct and correct in procedure when it comes to lab glass setups, however when it comes to these cells, it is nothing but a larger inconvience to try and fit/attach a reflux condensor (whether diy built from glass tubing in pvc such as minds condensors designs or conventional lab condensor), as the cell vessel is REALLY not air tight nor designed for attachment of a condensor... Think of a beaker, and how easily are you gonna attach a condensor? Not easily, it is better to take the route of rxn cooling to deal with the problem.

With ethanal its bp is twenty something C off the top of my head, and I can assure you, requires cooling, but the maa cell is the most convienant and inexpensive route to ethanal!

As for those whom decide to use the large 3 or 5gal vessels being pe buckets for the cell, these obviously don't allow for any feasible way to attach a condensor but do have ample space to work with sometype of submerged cooling apparatus. MiNd suggests sticking with glass and is easily made from glass tubing, though other options such as a U shaped piece of lead pipe [as bio suggested] would suffice as well, would xfr heat sufficiently, and not be prone to breakage.

Ultimately, Minds original post was soley to 'suggest' the use of computer power supplies (despite MiNd having mentioned such in the past) for the powering of these cells.. Inexpensive, common, and excellent performing they bee..

bio · Working Bee

Yea, really nice little setup you've got there!

The lead pipe can of course be used as an electrode as well as a heat exchanger. The patent I used as a guide for the electro Mn3 Acetate/Bz/Me2CO reaction ran at 70deg or reflux temp. It was found that temps below about 60 caused the muck to be unstirrable magnetically and overhad stirring would work but the goo was just to thick to function as an electrolyte.

The closer the electrodes the less resistance, therefor less heat is generated. The patent used 12mm but I settled on about 25mm for various reasons with the anode in a car battery bag. This really makes a big difference in the voltage required to reach the desired current density. I suppose that, without reliable info on max current density, as long as the yield doesn't suffer it's not too much. Rather simplistic but practical.

....On the topic of the acetate, which is pretty spendy and less common than the reagents for production of MAA, provides for an oxidant alternative [MAA] to the Acetate agent. ..........

Yep, costly stuff but easily made insitu from MnO2 or by refluxing the carbonate with GAA then throwing the Mn2 into the cell to be converted.

If making acetaldehyde some serious cooling would be needed. Air tight bucket lids are available and a heavy long neck of a HDPE or PP bottle can be cut off and attached to the lid. With a little judicious trimming with a sharp knife along with a roll of teflon tape a nice tight seal can be made to a male 24/40 joint..

MiNdBaBY · Mon Sep 12, 2005 2:50 am

bio, besides lol right, I'm very impressed with your impressive [to MiNd] level of diy (do it yourself) creativity.. Two thumbs up to you bio!

On other topics, your suggestion [quoted below] of using lead pipe as both an electrode AND cooling apparatus is pretty good idea and might be preferrable for some chemists out there.

....The lead pipe can of course be used as an electrode as well as a heat exchanger...

Regarding this good suggestion, MiNd would add that RUBBER leg ends/caps from the hardware store of various sizes then drilled out with a regular cordless drill and bit, are gods' gift to mankind, more accurately, to chemists.. These rubber stoppers allow for fitting various glassware (especially condensors) to any type of other glass vessel, besides working for plastic as well..

MiNd highly suggests sticking with rubber! It'd make such an design as bio suggests with regards to connecting a condensor (diy glass tubing in pvc pipe OR lab condensor) to a plastic poly bucket MUCH MUCH easier to get an air tight seal/fit than trying to size a hole in the plastic to adequately fit the glass and seal with just teflon.. lol, ya haven't tried such yet huh bio? But your damn good with your creative mind.. You definately can keep up if not surpass me.. Makes me wonder, are we related??? long lost brother or something.. Okay, I apologize for the humor if it offends you at all.

...With a little judicious trimming with a sharp knife along with a roll of teflon tape a nice tight seal can be made to a male 24/40 joint..

bio · Working Bee

Those rubber leg/stoppers are real handy but the hydrocarbons especially the aromatics ruin them fast. Down here I have a hard time finding them in the hard neoprene it's usually too soft. Boiling in some lye conditions them. Wrapped with the beloved teflon tape they last a while then I just rewrap the little suckers.

............ get an air tight seal/fit than trying to size a hole in the plastic to adequately fit the glass and seal with just teflon.. lol, ya haven't tried such yet huh bio?...........

No, not that way. The male joint is pushed into a 21/35 plastic (HDPE) bottle neck. Softening in boiling water needed here. The bottles are only 48mm so the shoulders can be flattened and welded to the bucket. A bulkhead fitting is maybe easier just make sure the gasket and plastic are compatible with the reactants/solvents. Also it helps to reinforce the lid where the hole is drilled with another piece of flat circular plastic like a jar lid or pieces cut out from another bucket lid.

MiNdBaBY · Mon Sep 12, 2005 11:20 am

"Those rubber leg/stoppers are real handy but the hydrocarbons especially the aromatics ruin them fast."
Not so in my experience thus far, they last awhile, at least the rubber stoppers I use and/or leg caps..

As for NaOH conditions, lol, again they work for a good while in my experience, but wrapping in teflon as you suggest is an excellent reccommendation..

bio, have you ever been able to obtain or find any sort of spray on/adhesive teflon material? I know, myself, I have tried to find/source such, and have been unnsucessful to date.. Kind of after a teflon spray on adhesive similar to the 3M spray on adhesive I use for other projects not to mention in the chemistry forums.

but overall, fuck, bio!! You've got me trippin on just how experienced and/or your diy mind'set that you possess! You continue to beyond impress me, and that is hard to do! You've peaked my interest now! Wanna go head to head on any specific project?? lol

I've got appx one week until I leave this half of the world, and I'm up for a challenge.. lol

I love your mention of softening in boiling water, roflmao, this brings to mind my often used method of boiling a glass of water in the microwave oven in order to soften some PE tubing in order to force into it some larger glass tubing (often an glass eye dropper)..

Well, should my posting ever cease, I give three thumbs up to you bio!!
You're definately one of us, good'ol'boys!

bio · Working Bee

No adhesive AFAIK but it can be used as hot glue although the gun would be pretty fancy me thinks.

Haven't tried it yet but the Teflon S is the only real DIY coating/paint as it's one coat and cured at home oven temps. So as long as you have an oven large enough to fit the piece in Teflon coated pipe or parts can be made in the comfort of your own home! I suppose it can be sprayed.

All the tech stuff is here at where else but Teflon.com

http://www.dupont.com/teflon/coatings/basic_types.html

MiNdBaBY · Mon Sep 12, 2005 12:11 pm

bio:

rofl,
As for ovens, I've pioneered high temp ovens though your probably unfamiliar with such and the very little I've shared online never was caught on by any..

In english I've pioneered besides being the theorist behind such, the modification of existing counter top toaster ovens or conventional standard household ovens for use as extremely high temp lab ovens for upto 1000C temps..

This thread is NOT the place for such, and I've shared publicly about as much as I'm about to, including my pioneering of methylamine and amphetamine/mda/mdama production utilizing such.. I'm just NOT sharing publicly any more than I have previously.

bio, if you request, and have earned such, I' willl forward pictures and explain such in PM's/emails.

but as for the diy teflon spray on coat's, this is something I've been desiring to do/experiment with, for sometime now, and never gotten around to as teflon spray on adhesive is not readily available to me, at least OTC, thus my lack of emphatically experimenting with such.

greenyppols · Thu Sep 15, 2005 2:29 am

Hi. I've built one of these cells from info gathered at another site.. I ended up with about 2500ml total in a 5000ml beaker

I seem to have a foaming problem. I did see some red coming off the anode before it was engulfed in about 1cm of foam...

I had it at 5 amps for an hour, but foam kept rising..(I have a 25amp rectifier)
I may simply need stronger stirring, but I dont know...

This is how I made the maa:
732.42g MnSO4 H20 (I had 750g, so I dumped it all in)..was very fine powder
308.32g (NH4)2SO4
800g h20
1925g H2SO4

Separated the precipate on the bottom of a 5000ml beaker..put the xtra oxidant in jars for future use..some quite a few bits were left on bottom of beaker...

Any ideas? Is the foam normal? It didnt go away, I scooped it out as it was rising then thought I'd better stop before messing up...