Author Topic: Electrolysis membrane  (Read 8560 times)

0 Members and 1 Guest are viewing this topic.

Bandil

  • Guest
Re: Electrolysis membrane
« Reply #20 on: November 02, 2001, 06:29:00 PM »
@sYnThOmAtIc>

A stainless steel cup? Interesting indeed, but there are some things i am not quite sure of here:

a)
Wont the metal be dissolved over time, because of various side reactions?

b)
How can it conduct current, when it does not allow ions to pass, which are the ones responsible for the current?

How are your yeilds using this method?

Regards
Peter

BTW: Great idea...


sYnThOmAtIc

  • Guest
Re: Electrolysis membrane
« Reply #21 on: November 03, 2001, 03:25:00 AM »
This is a little off topic but is realted to the electrochemical reduction.

Could the procedure for making pt and pd on carbon catalysts be applied to a section of carbon rod? As a pd/c electrode could be quite helpful to improving yields in the amination of ketones to sec. amines wiht an electrochemical cell.

sYnThOmAtIc

  • Guest
Re: Electrolysis membrane
« Reply #22 on: November 03, 2001, 04:31:00 AM »
I meant it doesn't allow the reactant molecules to pass but does allow current to pass. Dunno about yields as pinky is still piecing together a procedure for the reduction. But in tests his partitioned cell worked fine.

It consists of a dispensing vessel submerged in a glass carboy with top hacked off the carboy. The bottom of the carboy has a piece of graphite plate in the bottom cut to fit in the bottom. Then the carboy was filled halfway with NaCl solution and the vessel is lowered into carboy and filled with NaCl solution and a graphite rod is lowered into the vessel and a current is appied. Chlorine gas is evolved in the vessel and Iodine can be seen collecting on the graphite in little clumps.

With an acid solution substituted in the carboy and ketone/amine in vessel reaction should be a success if a proper cathode is used in the vessel.

terbium

  • Guest
Re: Electrolysis membrane
« Reply #23 on: November 03, 2001, 06:52:00 AM »
I meant it doesn't allow the reactant molecules to pass but does allow current to pass.
A stainless steel cup!!! I am beginning to suspect that you have zero knowledge of electrochemistry.

sYnThOmAtIc

  • Guest
Re: Electrolysis membrane
« Reply #24 on: November 03, 2001, 07:57:00 AM »
Gee which is exactly what I stated in the post about NaCl electrolysis it's not a big secret. Besides whats your itch today? If you have a better idea then post it and quit burning my ass. I'm just trying to help as much as I can with what I have. Hell I'm just barely old enough to be out of highschool and if I had about thirty grand maybe I'd buy some education in the field, if some other field doesn't interest me more.

Bandil

  • Guest
Re: Electrolysis membrane
« Reply #25 on: November 03, 2001, 10:47:00 AM »
@terbium>
Could you please comment why it is a bad idea? I woudl suspect that the steel walls, would work as either a intermediate cathode/anode, reducing/oxidizing, whatever product that has been reduced.

Regards
Peter

sYnThOmAtIc

  • Guest
Re: Electrolysis membrane
« Reply #26 on: November 03, 2001, 11:53:00 AM »
Cause stainless steel is the most unreactive metal to acids and strong chemicals without putting a bunch of impurities into the solution, while keeping the solutions in each compartment separate. Any pourous membrane is gonna leak some goods to be oxidized and lost resulting in a loss in yield. Unless you order a special and most likely expensive membrane of some sort. I'm trying to use the cheapest most readily available components while still obtaining good results.

 If this could be done with a pyrex dish and a few pencils and dog food bowls along with some wire and a transformer imagine what kind of leap this would be in the war. And I'd like to see the DEA keep people from buying graphite and stainless steel. HA!

Besides even if I'm no expert as you may be that is what this place is for to help each other  overcome thses bulshit restrictions. And quite frankly electrochemical reactions look the most promising in the defeat.

Anyway back to the subject. As long as the anode is not in contact with the stainless dish then no oxidation will occur in the compartment or else Cl gas would have evolved in it when powered up but it didn't only Cl came from anode and none at al from the sides of the dish, as was expected. So as long as the stainless steel is of reasonable purity then ther should be no problem with any side reactions.

Bandil

  • Guest
Re: Electrolysis membrane
« Reply #27 on: November 03, 2001, 12:28:00 PM »
I cant see how it would work, without working as anode/cathode at the steel wall. Something has to be oxidized/reduced in order for the system to conduct current. It is a good idea, but i have a hard time seeing how it is different from a one celled electrolysis w/o membrane. Sure the steel keeps the products from mixing, but the reduced PEA, would simply float to the steel wall and be oxidized.

Im not saying this as facts, its just the only way that i can make the system work in my mind. Please someone tell me that im wrong, as it would be a really easy way to do it!

Regards
Peter

lugh

  • Guest
Re: Electrolysis membrane
« Reply #28 on: November 03, 2001, 02:10:00 PM »

Hell I'm just barely old enough to be out of highschool and if I had about thirty grand maybe I'd buy some education in the field, if some other field doesn't interest me more




There's more than one way to skin a cat, in this particular instance a visit to a local public library (generally free  :) ) would exponentially increase your creativity. While education is a good thing, few universities teach electrochemistry  :(  

What terbium is getting at is the function of the cup/membrane/diaphragm in electrolysis is to allow certain ions to travel through the diaphragm and reach the electrode, while not allowing other species to penetrate. Obviously, stainless steel isn't permeable, and thus not suited for this purpose.


PrimoPyro

  • Guest
Re: Electrolysis membrane
« Reply #29 on: November 03, 2001, 02:22:00 PM »
Allow me to interrupt just once and very shortly:

lugh! CONGRATULATIONS on the promotion!  8)

Alright, Im done. (slinks away)

                                                  PrimoPyro

Vivent Longtemps la Ruche! STRIKE For President!

Bozakium

  • Guest
Re: Electrolysis membrane
« Reply #30 on: November 14, 2001, 11:31:00 PM »
Have you tried lambskin(not rubber) condoms? Fester has had good luck with these as cell dividers.

TrickEMethod

  • Guest
Re: Electrolysis membrane
« Reply #31 on: November 16, 2001, 06:27:00 AM »
I am somewhat out of date as to the status of everything, been on hiatus from the world of creative chemistry.  About six months ago, I was playing with the Fester
electrochem method with minimal success before I was so rudely abducted by aliens.

At that time I was using lamb skin condoms with no problems whatsoever, but I had rigged up a fairly effective ghetto CV/CC (constant voltage or constant current) power supply($100 from simple Walmart and Shack components).  I had also begun digesting several hundred pages of papers and books on the various factors governing electro chem reactions... cell design, current density, temp control, circulation, cathode\anode selection and solvents were all significant to the outcome of the reaction. 

I need to refamilarize myself with the subject for sure, but one thing stands out from what I gathered very distinctly; small or even unnoticed variations in the configuration can impact the results dramatically.  Since the literature provides a number of frameworks to anticipate and calculate the impact of many of these factors, I would encourage you to sketch a few impact estimations for yourself to get a ballpark feel for the significance.

It is well documented that subtle variations can lead to highly diverse outcomes, with many interesting possibilities for additional research identified but as yet resolved.  I learned first hand that propper control of the voltage potential, solution temp and monitoring shifts in the current flow were minimum ante for predictable results using this method.  Getting a successfull result from a car charger, run blind with ambient cooling would seem as likely as picking a catalyst, reaction temp and solvents at random.  It could happen... but not often.

I didn't mean to preach, and I certainly havn't perfected this strategy.  But I did become aware of some of the loose ends that were being under appreciated.

TrickE
BTW, if anyone is interested in construcing a powersupply it is described in an older post.  A $60 Shack multi-meter with rs-232 output is used to monitor the output of a PC driven power source.  The power source is simply a cheep($35) 80 watt audio amp driven by a PC sound card.  The amp delivers a modulated signal (AC), which is rectified and smoothed with a medium sized capaciter.  Software reads the meter and adjusts the 'volume' of the tone output to make necessary adjustments.  The software not only controlled the feedback loop, but as a bonus, plotted the effective conductivity using fairly basic factoring and estimation methods to provided helpfull clues to the progress of the reaction over time.  (actually this wasn't finished, but fairly staightforward)

And on the eight day, God created Meth...
... and hasn't done much of anything usefull since!

foxy2

  • Guest
Re: Electrolysis membrane
« Reply #32 on: November 16, 2001, 07:48:00 PM »
Nice TrickE

Are you going to write a comprehensive electrolysis FAQ when you get your apparatus built?

Do Your Part To Win The War

sYnThOmAtIc

  • Guest
Re: Electrolysis membrane
« Reply #33 on: November 17, 2001, 03:02:00 PM »
Alright how bout this one....

Fuel cells, they use noble metals/and oxides as electrodes some gas diffusion and solid that not being that important but the vulcan/nafion/and carbon cloth membranes can be bought cheap precut for use in a fuel cell or custom ordered sizes, but still cheap. Electrodes can be bought really cheap with a 20% loading by wt of a choice of sitloads of metals a few being  pt/pd/ru/ni/and their oxides for about 1-2 bucks per cm2 solid and porous some hydrophobic or teflon resin backed blah blah bla... they come on carbon or a variety of other mediums some specailly for use in acid and alkaline cells nafion112-117/vulcan xc72 with teflon coating would be good for chemical resistance .. so you can purchase the pieces and rig a setup or if you have simple machining equipment you can put together a fuel cell yourself for about 1/80th of what these price gougers sell theirs for and have a 3kw cell to help save on the electric bill. Or you really get into it and invest a lil the you can have all your electricity and vegies/spices for free as long as you have sun a water oh and a halide light or two. But back to the point, those who at least under stand the aspect of electro oxidations and reductions should see the usefulness in this if not then jsut ignore this post. Most all cells I have looked at are easily dismantled by removing the bolts from the sandwhich array which can then easily be altered for your purposes electrolysis/power generation oxidation/reduction blah blah yadda yada.

Bozakium

  • Guest
Re: Electrolysis membrane
« Reply #34 on: November 27, 2001, 07:48:00 AM »
Keep it simple and save your sound card, thats way too Rubie G-berg.. An LM317 voltage regulator can also be configured as a current regulator with only an additional resistor.   BUT You want to regulate voltage rather than current with electrochem rxns because the various reactions that can occur with a given compound are V dependant, and, while keeping V steady, current will fluctuate as electrolyte composition changes during the rxn.
 What I'm trying to come up with is an integrator circuit that(not integrated circuit, DUH) that will integrate current with respect to time (dI/dT) to give an output in coulombs. This would be very tidy since cell current varies and constantly plotting it is apain in the ass with other things to watch in the lab.
  OH yes, the fuel cell people have mannnny interesting things available...........

Bozakium

  • Guest
Re: Electrolysis membrane
« Reply #35 on: November 28, 2001, 07:58:00 AM »
I read in an old chem text that hollowed-out fruits and vegetables can be used. If you're interested, I'll look it up, or you can just experiment!Im serious.

Osmium

  • Guest
Re: Electrolysis membrane
« Reply #36 on: November 28, 2001, 03:11:00 PM »
What about hollowed out roadkill? W need a use for the hide too, after we isolated lactic acid, GHB and cadaverine from the meat and P from the bones.