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nh4clo4
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wink.gif posted on 10-12-2004 at 20:25
Electrolysis with molten sugar


If you were to perform electrolysis through molten sugar would it split it in to graphite and water?



Pleas respond :)
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solo
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[*] posted on 10-12-2004 at 20:48
Ref: Electrolysis with molten sugar


This might help you understand......solo

http://www.schoolresult.com/chemistry/electrolysis.htm




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darkflame89
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[*] posted on 11-12-2004 at 00:08


Obviously you do not understand electrolysis at all. Please take the pains to read up on it, not have other people to spoonfeed you.

Electrolysis does not work like that. It requires the presence of ions. Molten sugar does not contain ions, it is a covalent compound. Therfore, electrolysing molten sugar will result in nothing.

Decomposing sugar to carbon and water do not require electrolysis. All u need is to add conc. sulphuric acid to sugar.

Have a nice day studying your chemistry textbook.




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KemiRockarFett
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[*] posted on 22-1-2005 at 10:02


Quote:
Originally posted by darkflame89
Obviously you do not understand electrolysis at all. Please take the pains to read up on it, not have other people to spoonfeed you.

Electrolysis does not work like that. It requires the presence of ions. Molten sugar does not contain ions, it is a covalent compound. Therfore, electrolysing molten sugar will result in nothing.

Decomposing sugar to carbon and water do not require electrolysis. All u need is to add conc. sulphuric acid to sugar.

Have a nice day studying your chemistry textbook.


Very arrogant answer and its wrong.
Sure you need ions but in fact its possible to make electrolysis if you apply enough electric field, high voltage, and the substance have got an dipolmoment. Do you think pure water conduct due to its high H+ and OH- concentration at 10^-7 mol/dm3 ? Or because of it beeing an dipole that breaks up in H+ and OH- than an high voltage is applied.
In fact if you want to split upp water you add som ions for example sulfuric acid to carry the current more effective but what is formed? persulphates and hydrogen and oxygen so the summary will be electrolysed water and the same is very possible and has been done on different sugars for more than hundred years ago.

For example an aqueous glucos solution go over to mannit via electrolysis at the cathode.
Its very well known that chemists know a days is so bad in electrochemistry that is a fact.
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vulture
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[*] posted on 22-1-2005 at 13:43


You can't electrolyse molten sugar for the simple fact that it decomposes when molten...



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Theoretic
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[*] posted on 22-1-2005 at 14:26


"Very arrogant answer and its wrong."

Bullshit. What's wrong? That you need ions for electrolysis? That nh4clo4 doesn't understand electrolysis and is showing it by suggesting you can electrolyse molten sugar to water and graphite? That he should educate himself on the subject and spend some time reading his textbook?
And his post was in the wrong section as well...
"Sure you need ions but in fact its possible to make electrolysis if you apply enough electric field, high voltage, and the substance have got an dipolmoment. Do you think pure water conduct due to its high H+ and OH- concentration at 10^-7 mol/dm3 ? Or because of it beeing an dipole that breaks up in H+ and OH- than an high voltage is applied."

:o What are you TALKING about? Pure water is an insulant, it's the impurities that let it conduct. You think that liquid formaldehyde can be electrolysed? Sure, it has a dipole moment, but does it really matter? If it doesn't ionise then it won't conduct. Does methylene chloride conduct?

"In fact if you want to split upp water you add som ions for example sulfuric acid to carry the current more effective but what is formed? persulphates and hydrogen and oxygen so the summary will be electrolysed water and the same is very possible and has been done on different sugars for more than hundred years ago."

Specify an example, please.

"For example an aqueous glucos solution go over to mannit via electrolysis at the cathode."

Reduction by nascent hydrogen maybe?

"Its very well known that chemists know a days is so bad in electrochemistry that is a fact."

Very well known? A fact? Where's your data coming from? You sure don't know too much about electrolysis yourself, since you think that methylene chloride can be electrolysed (and everything else with a dipole moment) and think that "electric field, high voltage" are two different things when in fact electric field is created by a voltage difference.

"Have a nice day studying your chemistry textbook."

[Edited on 22-1-2005 by Theoretic]




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KemiRockarFett
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[*] posted on 22-1-2005 at 14:39


Quote:
Originally posted by vulture
You can't electrolyse molten sugar for the simple fact that it decomposes when molten...


Thats very very true ;)
But I am sure that you are understanding the thing that I tried to explain. A compound does not nead to be ionic at all to obey electrolysis. ( BUT it must be possible to form ions carrying the electrons, or you add something wich is ionic and run the electrolys on it)
The best thing with electrolysis is that one can do so much chemistry with it. BUT very many chemist does not now a shit about it. For example in Sweden there I live at the universitys they have no research at all on electro chemitry, yes okey at corrossion maybe. And than talking to some old professors they find everything about electrolysis out of water as strange. Some of them have applied it in organic synthesis but thats not so common either due to the fact that organic chemists often hate things like electricty and calculations and mathematics, and the inorganic chemists often sucks totaly on chemistry because they are more interested to estimate celledges with x ray diffraction and neutron data. A real chemist should be specialised in all the fields !!

[Edited on 22-1-2005 by KemiRockarFett]
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[*] posted on 22-1-2005 at 14:53


Quote:
Originally posted by Theoretic
"Very arrogant answer and its wrong."

Bullshit. What's wrong? That you need ions for electrolysis? That nh4clo4 doesn't understand electrolysis and is showing it by suggesting you can electrolyse molten sugar to water and graphite?


Yes you need ions and you will form them than you applie pluss and minus on a system that is polarisable. Do you think all things obeying electrolysis is ionic for example Al2O3? haha no way the ionic character in Al2O3 is little !!!! Its an covalent compound which electrolyse quite well.

In this forum you have got an big text file several hundered sides in a book inscannad to download I think its under this session. I think you should read it. Its old but it shows a lot of fashinating electrolysis:
http://www.archive.org/details/ElectroChemistryForOrganicCom...


[Edited on 23-1-2005 by chemoleo]
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[*] posted on 22-1-2005 at 22:07


Do you have a spelling problem, or are you just too lazy to make yourself clear?



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BromicAcid
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[*] posted on 22-1-2005 at 22:26


Please, let's keep things civil.

By definition:
The properties of ionically bonded substances:
Hard
Conduct heat and electricity (when molten or in solution)
High melting points

The properties of covalently bonded substances are:
Low melting point
Insulators of heat and electricity

Al2O3 is indeed ionic, the differences between ionic character and covalent character could easily be shown by comparing MnO2 to Mn2O7, the latter showing considerable covalent character. Electrolysing molten Al2O3 does indeed give aluminum metal. Yes, you can electrolyse molten sugar just as you can air, run enough current and volts through any insulator and you can jump between electrodes as long as the distance isn't too far, doesn't mean you'll get anything productive or even that you're doing electrolysis. Look through that book you just linked us to, the reactions with organic chemistry and electrolysis usually take advantage or some reactive molecule formed at an anode or cathode doing its buisness with the organic molecules around, not the organic molecules doing the direct reaction. For example this article on Industrial Electrochemical Organic Synthesis has one distinctive paragraph that goes over the intermediate compounds formed:
Quote:
There are many other differences seen in organic electrosynthesis compared to conventional organic synthesis. Useful concentrations of highly reactive cation or anion radicals, not easily or so far impossible to make chemically, can be easily and conveniently produced electrochemically. The resulting electrosynthesis products can be unique (that is not before synthesized by chemical means, or so difficultly made by chemical means that many steps would be required). Many other reactive species can be made conveniently, including superoxide ion, hydroxyl radicals, peroxide, CO2 anion radicals, hydrogen atoms and metal hydrides, and halogens, including fluorine. On the cathode side of the cell, at high negative potentials, solutions of solvated electrons can be readily made and on the anode side, at high positive potentials, powerful oxidants like fluorine, persulfate salts, and ozone. Acid can be made at the anode and alkali at the cathode.
Most of the organic electrosynthesis reactions involve inorganic ionic compounds added that serve as the intermediates, yes, some electrochemical reactions can happen directly on the organic molecules, but there are other factors involved too.



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[*] posted on 22-1-2005 at 23:02


While we're on the topic of sugar...

When heated what does it decompose into? Amorphous carbon or graphite? Also, if it's amorphous carbon, when does that change into graphite? (assuming standard pressure) Sorry if this is spoonfeeding, but I've done the mandatory google search many times.

Here's another thing I've heard on the internet-

~
When graphite is intercalated with sulfuric acid, graphite sulfate is formed. On rapid heating this is transformed into a voluminous worm-like mass similar to the expanded vermiculite used in potting mixtures. This mass is compacted by rollers into foil which is used to make gaskets, which substitute for asbestos. The graphite foil resists high temperatures and chemicals. US consumption is about half of that of the world. Russian researchers have identified that expanded graphite is an excellent adsorbent for oil spills.
~

http://industrialmineralsinc.com/about.html
~

Graphite sulfate? :o Kind of interesting.




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darkflame89
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[*] posted on 23-1-2005 at 00:56


I am sorry over my controversial answer. Pure water can be electrolysed if you apply a high enough voltage. And excellent example is:http://www.powerlabs.org/waterarc.htm
But we are talking about conventional current and voltage here, and electrolysis generally applies to ions, though certain organic molecules can be oxidised or reduced, but this is more complex. I only meant nh4clo3 to start from the basics first.




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KemiRockarFett
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[*] posted on 23-1-2005 at 02:14


Quote:
Originally posted by BromicAcid
Please, let's keep things civil.

By definition:
The properties of ionically bonded substances:
Hard
Conduct heat and electricity (when molten or in solution)
High melting points

The properties of covalently bonded substances are:
Low melting point
Insulators of heat and electricity


Yes that is a good explaniation of my posts. You run the electrolysis over some other substance added to the substance, for example sulphates which will produce persulphates of different kind at the anode and this substance do an oxididation of the other compound in the mix and go back to sulphate and over and over again.
What I meant by all my posts was only that you point out, and that is if you have extremly high voltages you can bump electricity in most things.
But that is not the case in ordinary electrolysis so the anwer to guestions like: Can I electrolyse acetone, sugar solutions and such things? No should be the answer, but you can add ions of some other materials to do interesting chemistry with electrolysis etc.


( Due to my spelling, every mod good in english feel free to correct my spelling I spell as good as I can )

Edit by C.: Please dont quote FULL messages! As to spelling...aren't there fantastic inventions such as spell-checking programs?



[Edited on 23-1-2005 by chemoleo]
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chemoleo
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[*] posted on 23-1-2005 at 08:27


I think the logic of the original poster is

NaCl --> electrolysis --> Sodium at the cathode, chlorine at the anode

Sugar ('Carbon-hydroxides';) --> electrolysis --> Carbon at the cathode (plus hydrogen), oxygen at the anode.

Shame only sugar isn't ionic.
Kemi, what you are on about is something else than the answer to the original question, and the original answer by darkflame is certainly NOT wrong.


Cyrus, are you aware of any instance where a chemical decomposition of an organic molecule yields graphite?
I always thought graphite is produced when ordinary carbon is pressurised.




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[*] posted on 23-1-2005 at 08:35


Now that Cyrus mentions graphite intercalation compounds, I read about graphite nitrate in the nitration book I mentioned in the nitroalkane thread.

Something there said that it is used for nitration much like nitric/sulfuric acid.

I will post more about it once their words get through my thick skull.

Oh, and the carbon produced by pouring vitriol on sucrose is amorphous. Not enough time to order itself into the neat hexagonal array that is graphite.

Since that was off-topic, I should mention that a good number of compounds decompose when subjected to a sudden influx of current (but that is more often due to the heat produced), but I do not at all believe that this was what nh4clo4 had in mind.

sparky

P.S.

Quoting KemiRockarFett:

"(sic) ...A real chemist should be specialised in all the fields..."

That was oxymoronic. How can you specialize if you're into everything?
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[*] posted on 23-1-2005 at 22:20


Chemoleo, as a matter of fact, I am aware of an organic decomposition that produces graphite. ;)

Wood. Seriously. I was just doing some ceramics tests (again!) and was heating a crucible on top of a block of wood. The bottom of the crucible had nice areas of quite shiny, adhesive, and electrically conductive graphite on the bottom after being heated. It didn't get above an orange heat IMO either, so this is something anyone can try- heat a plate (not paper) on top of a piece of wood (not the table).

Yesterday I was doing some other tests in my furnace using wood and coal, and some of the pieces then had even nicer shiny graphite spots.

I'd like to try "graphitizing" things by heating them in a closed chamber with wood.

Also, do a search on "pyrolytic graphite" IIRC methane is used.

Sorry, this is OT- new thread maybe?

[Edited on 24-1-2005 by Cyrus]




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[*] posted on 24-1-2005 at 12:56


And than talking to some old professors they find everything about electrolysis out of water as strange. Some of them have applied it in organic synthesis but thats not so common either due to the fact that organic chemists often hate things like electricty and calculations and mathematics, and the inorganic chemists often sucks totaly

As an organic chemist by trade a quick comment.

If the old professor or the organic chemist did not like electric how do LCD screens work. If they electrolysed I do not think they would last very long.
I think MRI came from NMR + computers. I work in a place where having a super cooled , super conducting magnet is routine. Fill it up with liquid N2 every week and the liquid He (at near absolute zero) needs topping up every 3 months. Electric zero, keeping it cold costs.
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[*] posted on 26-1-2005 at 15:42


I doubt most of you have it, but in a pyrotechnic book I have, they actually have a way to make graphite at standard pressure. It is part of the charcoal making proceedure, with things to avoid. You can convert an amount of wood to pure graphite at 1000C for 24 hours. I think it is 2 pounds of charcoal going to 95+% graphitic structure. I had have some lampblack laying about, it is highly unconductive. I heated about 15g with a natural gas flame for about 5 hours. I was suprised when I got a decently conductive material. I think heating any carbon structure will go to graphite. Charcoal would go faster than a totally amorphous form in my opinion. The heat closes the broken graphitic ring structures, which is one of the main reasons that charcoal is much better in pyrotechnics than graphite, and more reactive.

The book is Black Powder Manufacturing, Testing & Optimizing

By Ian von Maltitz
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JohnWW
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[*] posted on 27-1-2005 at 02:31


You had better scan to PDF or DJVU your book "Black Powder Manufacturing, Testing & Optimizing", and upload it to the FTP, then.
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[*] posted on 27-1-2005 at 16:19


It's already scanned and OCR'ed in pdf. I think it is that book. It is at my other house, but I looked on Skylighter and it is the one that mentioned charcoal testing. The only problem is that it was scanned by another person. I'll see if I can get permission from him for an upload. He is really nice about stuff like this, so he'll probably go for it. If not I could make an excerpt of the graphite part.
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[*] posted on 27-1-2005 at 22:57


I think it is a mistake to assume that most of the carbon atoms in lampblack are not in the form of intact hexagonal lattice sections. Lampblack is suitible for oxidation to mellitic acid for example. The graphite layers only conduct in 2 dimensions so fairly long range order is needed for a decent effect in a bulk powder/solid.

I'm happy with the convensional pore/volatiles explanation of the performance, or lack of it, of graphite in black powder mixtures unless you have more info.
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[*] posted on 28-1-2005 at 16:03


While we're on the offtopic of carbon, what is the easiest way to get colloidal graphite?

The smallest size carbon I know how to get is lampblack, which I could then heat treat in my furnace to get some graphite.

The reason I ask is that I need to electroplate something large, (yes still haven't done that) and it's a plastic. So I need a conductive coat first- apparently aquadag can be used, which is water, and graphite peptized by tannin. This vould be sprayed on the plastic part, and then immersed in a electroplating bath. (with CuSO4, H2SO4, etc)

VVould the tannin mind? I'm vorried that the graphite solution will just "dissolve" off in the plating bath. :o




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[*] posted on 28-5-2015 at 13:05


in fact, with the proper compounds in place it can be done:
http://nvlpubs.nist.gov/nistpubs/jres/6/jresv6n6p1145_A2b.pd...
but there will be no graphite and/or water




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[*] posted on 28-5-2015 at 13:13


10 year old thread, and i still can't see why they didn't just try it and see.

Not as if it'd be a difficult or expensive process.




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[*] posted on 28-5-2015 at 13:18


Quote:
Yes you need ions and you will form them than you applie pluss and minus on a system that is polarisable. Do you think all things obeying electrolysis is ionic for example Al2O3? haha no way the ionic character in Al2O3 is little !!!! Its an covalent compound which electrolyse quite well.


Who does electrolysis of alumina without dissolving it in molten cryolite (sodium hexafluoroaluminate, in which it will ionize) first?

[Edited on 28-5-2015 by DraconicAcid]




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