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moxsnixs
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yeah I know but Im in another country and customs dont like chems. And although it was interesting to do,if I was to need it again I'll drive the 3hrs
one way and buy it.The trouble is the beautiful women there........can't leave till I get one 
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moxsnixs
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Could ammonium chloride be used instead of the sulphate ?
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12AX7
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Chloride is oxidized by Mn(III) or (IV).
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moxsnixs
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For the washing of the extracted benz. is it DH2O only? thanks
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Hilski
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| Quote: | | For the washing of the extracted benz. is it DH2O only? thanks |
I have used both plain DH2O as well as a saturated NaHCO3 solution to wash the benzaldehyde/toluene mixture. This is done to remove as much acid and
other byproducts as possible to reduce the amount of red tar produced during distillation. I haven't noticed much difference in the results between
water or NaHCO3. Once I get the up-scaled MnSO4(IV) cell going, I think I may try using steam distillation to get the product out instead of doing
extractions.
\"They that can give up essential liberty
to obtain a little temporary safety
deserve neither liberty nor safety. \"
- Benjamin Franklin
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CycloKnight
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Mood: Still waiting for the emulsion to settle.
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Nice work Hilski, lots of potential with this manganous-alum route. Great pics BTW !
This thread sure brings back memories 
[Edited on 13-2-2007 by CycloKnight]
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Eclectic
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Ok, I got a case of these, and they seem to be perfect for electrochemistry experiments. When filled with water, the outside gets wet and "sweats"
on the lower half after about 5 minutes. The clay is an off white low iron type.
http://www.maycocolors.com/shapes/shapeDetails.cfm?shape=101...
Low fired porous ceramic bisque.
[Edited on 14-2-2007 by Eclectic]
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Rosco Bodine
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Hehehe ....looks like the mother of all porous cups
It should work very well too , *if* it holds up okay in the
pretty strong H2SO4 which is used for the electrolyte in this process .
Buying a case of them , hmmmm ...you must be confident .
Let's just hope it isn't a "case" of only .......
"hope springs eternal" and/or
advance christmas shopping for that perfect gift
for all your wino friends
I just had an idea that maybe a 100 ml mixing cylinder is placed inside , it would make a perfect water cooled cathode form for wrapping sheet lead
around .....fitted with a two whole stopper with one long tube nearly to the bottom , and one short tube .....circulate cooling water through the
cylinder , and you could really put some Amps through the thing . It would keep the electrode nicely centered too .
[Edited on 14-2-2007 by Rosco Bodine]
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Eclectic
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$42 for 6 including S&H. Google for the best price. They are made out of clay fired at cone 4, so they are just as chemically resistant as any
other ceramic.
I was thinking they would also make a good substrate for lead dioxide. If you could get a good heavy plating, then the connection could be made
through an electrolyte and electrode on the inside.
[Edited on 14-2-2007 by Eclectic]
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Rosco Bodine
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Outstanding . You could build a serious electrolytic cell
of coaxial electrode arrangement , having that component as the porous cup . This is great , it looks like the tyvek works for a divided cell , and
this will probably work fine too
Hmmm. I'm thinking maybe as this progresses we should have a new specific topic category for Electrochemistry , for all related reactions and
equipment , literature , ect.
I know it is included as a part of " Technochemistry " now
but that is sort of an ambiguous name ....
since *all* chemistry is actually pretty " technical "
What do you fellows think about this ?
[Edited on 14-2-2007 by Rosco Bodine]
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Hilski
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| Quote: | | Hmmm. I'm thinking maybe as this progresses we should have a new specific topic category for Electrochemistry , for all related reactions and
equipment , literature , ect. |
I'll second that. Electrochemistry is the branch I have always been the most interested in, so I would love to have it broken out into it's own
forum.
And those wine coolers that Eclectic has look like they would work well for large cells. I have some large Pyrex graduated cylinders that would work
for the electrode cooling jacket inside those containers. If you try to plate PbO2 onto those, I would definitely like to have some details on how
that project goes.
| Quote: | Nice work Hilski, lots of potential with this manganous-alum route. Great pics BTW !
This thread sure brings back memories |
Thanks! I have to give you the credit though. I got the idea and most of the information I needed to do this (the alum) from your posts and
pictures. I am anxious to try out the Mn persulfate on a similar scale, so I can make a yield comparison with the alum. I am working on a 3 liter
divided cell which will have overhead stirring, so hopefully, I will have some aldehyde production results to post within the next week or two.
\"They that can give up essential liberty
to obtain a little temporary safety
deserve neither liberty nor safety. \"
- Benjamin Franklin
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roamingnome
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as i was saying
i have been swayed by the anode side of the force...young experimenter
but to clarify, in this divided cell only MnSO4 is used, with acid of course
the ammonium sulphate is not needed now to protect the charge.
the jedi arts are proliferating
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Hilski
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| Quote: | but to clarify, in this divided cell only MnSO4 is used, with acid of course
the ammonium sulphate is not needed now to protect the charge. |
Yep. That is correct.
\"They that can give up essential liberty
to obtain a little temporary safety
deserve neither liberty nor safety. \"
- Benjamin Franklin
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Rosco Bodine
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There is a smaller part that may work also
with a smaller scale cell .
This is 3.25"D X 4"H
http://www.maycocolors.com/shapes/shapeDetails.cfm?shape=203...
Also see this page for all the Mayco bisque .
http://www.ceramicssf.com/maycobisqueware.htm
About halfway down the page on the right is a " message bottle " and it looks like it might make a better substrate
for PbO2 and using an electrolyte inside for the connection .
I am not quite sure if in the case for this being used as the anode , that there may not be some gassing on the surface of the electrode in the
interior electrolyte due to the slight
voltage drop ....or what electrolyte would be useful . It seems possible that some series voltage differences might
be problematic for making the connection internally via an
electrolyte . That whole idea is very interesting , but not guaranteed to work because of the unknowns ...I think
[Edited on 23-2-2007 by Rosco Bodine]
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Hilski
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Since the site got hacked, and was going to be down for a few days, I figured I should try something constructive in the meantime. So I decided to
make some more Mn(SO4)2 aka. Manganese persulfate, or Mn(IV), and oxidize something with it. So I preceded to use a terracotta cylinder I picked up
at a local craft type store and make a divided cell.
I dissolved 450 grams MnSO4 in about 2.5 liters of 55% H2SO4, and placed it in the anode compartment of the cell. I decided to use the inside of the
terracotta vessel as the anode compartment, because it was just more convenient. I electrolyzed the mixture at 12 volts, 3 amps for about 24 hours,
with current control being provided by a 50 watt DC light bulb in series with the cell. There was no heat created at all, so next time I will add
another 50 watt light bulb in parallel with the other one to up the current to around 6 amps. I stirred the mixture vigorously 4 or 5 times during
the 24 hours, and that seemed to be enough.
After the electrolysis was complete the mixture was kind if thick, and a very deep brown color. Most of the Mn(IV) was dissolved in the acid, but
there was some black sludge at the bottom of the cell that needed to be stirred around in the acid so it could be poured out into the reaction vessel.
I used a 1 gallon glass jar for the reactor, which worked pretty well. To the reactor I added the 450 grams Mn(IV) in about 2.5 liters 55% H2SO4,
along with about 210 ml toluene. I decided to try the reaction at room temperature, so a homemade overhead stirrer was set up and the mixture was
stirred vigorously overnight (probably about 12 hours).
When I went back to check on things, I was somewhat surprised to see the the reaction had proceeded nicely and was totally complete. The deep brown
solution had turned to a light brown sand color, and the the smell of benzaldehyde inside the vessel was almost overwhelming . The scent of toluene
was not detectable at all, so I am guessing that nearly 100% conversion was achieved. This is not a good thing though, since some benzoic acid was
produced, and was floating in a layer between the acid and the benzaldehyde as can be seen in the picture. This problem can be remedied by simply
using a larger volume of toluene, so that there is an excess compared to the oxidizer.
Extraction was a little bit tedious because of the benzoic acid, but not too bad. I added another 100ml of toluene to mixture and decanted most of
the product, and used a syringe to remove the remainder that I couldn't pour off. I haven't distilled anything yet, so I can't give any info on
yield. But I am guessing that it will be pretty good, probably between 150 and 250 ml. I will update this post once I do have the final results.
I forgot to take a picture of the Mn(IV) before I started the reaction, but here it is after it has been reacting for a few hours. You can see some
of the lighter colored brown oxidizer at the bottom that has already been reduced by the toluene. Remember that the mixture was totally black before
I started.
Here is the reactor after the oxidation is complete. You can see the organic layer, which was a bright yellow color after it was extracted.
So far I am pleased with the results of this experiment, and if yields turn out to be pretty good, I would definitely consider this a good,
relatively simple method for producing aldehydes.
[Edited on 8-3-2007 by Hilski]
\"They that can give up essential liberty
to obtain a little temporary safety
deserve neither liberty nor safety. \"
- Benjamin Franklin
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roamingnome
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AEM’s in general
What are the short comings of the tyvex membranes? I rather liked the concept…
Thinking about using Teflon tape PTFE maybye too.
Reading about the preparation of these membranes, it seems that net positive charges are impregnated in the polymer matrix as they make it….
Is the SiO2 or some component of the terra cotta pots giving it a net positive charge to repel cations?
Also what is the cathode reaction?
From: http://ocw.mit.edu/NR/rdonlyres/Materials-Science-and-Engine...
PbO2 + 4 H+ +2e- + SO42- ---> PbSO4 + H2O
Alittle benzoic acid doesn’t seem to cancel the show  good stuff....
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Hilski
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| Quote: | What are the short comings of the tyvex membranes? I rather liked the concept…
Thinking about using Teflon tape PTFE maybye too. |
The electrolysis takes place fine using tyvek as a membrane, but it was rather akward to work with, when trying to cover a large vessel with it as I
was. I also noticed that over time, the electrolyte (the anolyte in my case) inside the tyvek covered vessel would slowly seep through into the
catholyte. This wasn't a huge deal since the catholyte was the same composition as the anolyte, and could simply be added back into the anode
compartment. I chose to use terracotta because I found some 1.5 liter cylinders that did not have a hole in the bottom, at a local craft store for
$3.00 and they worked very well for these purposes.
| Quote: | Reading about the preparation of these membranes, it seems that net positive charges are impregnated in the polymer matrix as they make it….
Is the SiO2 or some component of the terracotta pots giving it a net positive charge to repel cations? |
I have no idea. Roscoe might have to answer this one for ya.
| Quote: | | Also what is the cathode reaction? |
As far as I know, the reduction reaction is the same as with a lead acid battery; I have seen this written as:
PbO2 + HSO4- + 3 H+ + 2 H+ --> PbSO4 + 2 H2O
The reaction you posted is probably correct as well.
The benzoic acid really isn't a big deal. Most of it can be strained out with a small SS strainer with no problem. It doesn't dissolve in the
saturated H2SO4/Mn solution, and floats on top after the benzaldehyde has been removed. Organic material that remains in the cell supposedly lowers
current efficiency during regeneration, but I could care less about that.
[Edited on 9-3-2007 by Hilski]
\"They that can give up essential liberty
to obtain a little temporary safety
deserve neither liberty nor safety. \"
- Benjamin Franklin
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jimmyboy
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so you placed a terra cotta container inside another larger one - and used the ceramic as the membrane (generating the alum inside the pot instead of
outside) - the larger container catching most of the bubbling? this worked very well from what it looks like..
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Hilski
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| Quote: | | so you placed a terra cotta container inside another larger one - and used the ceramic as the membrane (generating the alum inside the pot instead of
outside) - the larger container catching most of the bubbling? this worked very well from what it looks like.. |
Correct. I used a big glass jar for the outer container, and set the clay vessel inside of it in a coaxial type arrangement. The glass jar could
just have well have been a plastic bucket, or anything else that is acid resistant. Pretty much all the foaming took place in the outer container
like you said, and presented no problem at all. I'll post a picture of the contraption as soon as I get a chance. I still need to get off my arse
and distill the stuff so I can see what the actual yield was. But I'm crossing my fingers that it will be 70% to 80% or better. 
*Edit* I just noticed that you were referring to this oxidizer as 'alum'. This stuff is just MnSO4 oxidized to Mn(SO4)2. No alum this time.
[Edited on 11-3-2007 by Hilski]
\"They that can give up essential liberty
to obtain a little temporary safety
deserve neither liberty nor safety. \"
- Benjamin Franklin
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Coldfinger
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would benzyl alcohol be able to be oxidised to the aldehyde also? or would it over-oxidise to benzoic acid? maybe less time in the reactor would do
the trick? 6 hours as opposed 12 maybe?
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roamingnome
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In the PAIRED ELECTRO_OXIDATION
J. of applied Electrochemistry 1987...
jiin-jang etal.
proposed
C6H5CH3 + 4M(n+1)+ + H2O ------- C6H5CHO + 4M(n+) + 4H+
basically a 4 time molar amount of Mn is needed is what im gathering there.
they were also using 6M acid which would be very conveinent since i think this is very close to H2SO4 with a specific gravity of 1.256 which
refreshes regular batterys.
Are you useing 55% acid to disolve more salt per given volume? Or other papers use differnet concentrations....
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Hilski
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| Quote: | | would benzyl alcohol be able to be oxidised to the aldehyde also? or would it over-oxidise to benzoic acid? maybe less time in the reactor would do
the trick? 6 hours as opposed 12 maybe? |
There is a procedure in US patent 780404 for oxidizing benzyl alcohol with Mn(IV) sulfate. It describes adding the oxidizer drop by drop to an
emulsion of the alcohol with H2SO4 at 50C. One might be able to skip the tedious dropwise additions, and just put everything in the reactor at once if
things are done at room temp or cooler. But I have no way of knowing for sure. Patent 0808095 mentions the oxidation of methanol with the alum to
obtain methylal, formaldehyde, or formic acid but I don't know of a written procedure for oxidizing benzyl alcohol with the alum.
| Quote: | C6H5CH3 + 4M(n+1)+ + H2O ------- C6H5CHO + 4M(n+) + 4H+
basically a 4 time molar amount of Mn is needed is what im gathering there.
they were also using 6M acid which would be very conveinent since i think this is very close to H2SO4 with a specific gravity of 1.256 which refreshes
regular batterys.
Are you useing 55% acid to disolve more salt per given volume? Or other papers use differnet concentrations.... |
Judging by the reaction from the journal article you referenced, it would appear as though a 4:1 molar ration is needed. But none of the patents I
have read that pertain to the oxidation of toluene with Mn salts use that ratio.
For example, the Paired Electro Oxidation article you mentioned, uses a pretty dilute anolyte at only 0.1m Mn2+. This equates to only 5.5g manganese
per liter. (I assume the author meant 0.1M elemental Mn. If he meant MnSO4, then the ratios are even worse than I thought.) With the experiment
described in the paper, the authors used 250ml of the 0.1m Mn3+ solution to oxidize 50ml (43g) toluene. The molar ratio in that experiment was 1:18.8
Mn:toluene. How that could have possibly worked is beyond me. Especially when in the same article the author says that a 4:1 ratio is needed. The
Max Bazlen patent for production of Mn(SO4)2 and oxidation of toluene, recomends 600g Mn(IV):300g toluene, which equates to about a 1.4:1 molar ratio
of Mn:toluene. The maganese-ammonium alum patent states that a ratio of nearly 12:1 w/w of oxidizer to toluene should be used, which is a ratio of
roughly 5:1 Mn:toluene. The only thing that is common to all the patents and articles is that it is recommended to carry out the reaction at ~50C.
The 6M acid solution in the same paper you mentioned is about 46.5% by weight. The specific gravity would be ~1.36. The concentration I have used is
about 8.1M or 55% by weight. The reason I used that particular concentration is because that is what is called for in both Bazlen patents, as well as
in the alum patent. A 6M concentration may work fine, but I remember Cycloknight having issues with too much benzoic acid being produced if the acid
was too weak, so I haven't tried anything weaker than 55%.
\"They that can give up essential liberty
to obtain a little temporary safety
deserve neither liberty nor safety. \"
- Benjamin Franklin
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Coldfinger
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| Quote: | | Originally posted by Hilski I haven't distilled anything yet, so I can't give any info on yield. But I am guessing that it will be pretty
good, probably between 150 and 250 ml. I will update this post once I do have the final results. |
is there any results regarding yields from your latest experiment?
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raiden
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Sorry for reviving such an old thread - but I'm going to give this a swing.
At the moment I am waiting for the MnSO4 to dissolve, am using the amounts in the original post. My mag stirrer seems to be having trouble getting any
agitation at all, do you guys think it will dissolve by itself if left to its own devices? Going to be doing my run with a pool chlorinator MMO anode
at around 12 amps.
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manimal
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No. Use overhead stirring (nickel or HDPE stirrer).
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