Sciencemadness Discussion Board - Making Lithium Carbide

Making Lithium Carbide

symboom - 10-10-2011 at 09:21

any suggestions on production of this

It was first produced by Moissan, in 1896 who reacted coal with lithium carbonate.

To prepare pure samples in the laboratory molten lithium + graphite are reacted at high temperature.

Li2C2 can also be prepared by reacting CO2 with molten lithium.
this one seems to be the easiest to achieve temperature wise.
which seems to make not very much since because magnesium burns in CO2 and forms magnesium oxide and carbon.this would be saying that the reaction is 2Li + CO2 -> Li2C2 + 2O2

[Edited on 10-10-2011 by symboom]

ScienceSquirrel - 10-10-2011 at 09:26

I could ask why?
Calcium carbide is readily available and reacts with water to form acetylene.

symboom - 10-10-2011 at 09:32

Quote: Originally posted by ScienceSquirrel

I could ask why?
Calcium carbide is readily available and reacts with water to form acetylene.

yes it is but im wanting to experiment with alkali metal acetylides
as planning to use it as a reducing agent in a few experiments.

ScienceSquirrel - 10-10-2011 at 09:35

I doubt it will act as a reducing agent. What makes you think that it will?

ScienceSquirrel - 17-10-2011 at 06:12

Lithium carbide is the only carbide formed by reaction of lithium metal and a suitable carbon source eg finely milled graphite or charcoal.

http://en.wikipedia.org/wiki/Lithium_carbide

http://www.springerlink.com/content/b0v12x7v6255g755/

The steel furnace under vacuum might be a bit beyond most amateur's pockets though

bfesser - 17-10-2011 at 07:50

<del>Please stop bickering and stay on topic. He wants to make lithium carbide--the question of why does not matter. The equation looks insane, yes, but tell him why. Don't just mock him. Let's get some data, references, and analysis going, damnit! Were not here to belittle one another, we're a supportive community for the otherwise outcast practitioners of a hobby that's usually frowned upon.

Starting point for bringing thread back on topic:</del>

<a href="http://en.wikipedia.org/wiki/Lithium_carbide">Wikipedia article on lithium carbide</a>

[edit]
To further help you along, we're going to need this article:

U. Ruschewitz, R. Pöttgen (1999). "Structural Phase Transition in Li2C2". Zeitschrift für anorganische und allgemeine Chemie 625 (10): 1599–1603. doi:10.1002/(SICI)1521-3749(199910)625:10<1599::AID-ZAAC1599>3.0.CO;2-J.

I've requested the paper for you in the <a href="http://www.sciencemadness.org/talk/viewthread.php?tid=15455&page=10#pid224820">appropriate thread</a>--which I've been hogging lately, sorry.

Once it's openly available, I'll link it here.

[Edited on 2.10.13 by bfesser]

Neil - 17-10-2011 at 09:19

attached PDF suggests a route that is under 800° with pyrolysed carbon and lithium metal.

Attachment: LithiumCarbide.pdf (566kB)
This file has been downloaded 791 times

symboom - 20-10-2011 at 12:28

that makes a whole lot more sense Li + CO2 --> LiO + Li2C2
i know unbalanced
but it cover the jest of the reaction as some of the lithium reacts with the oxygen from co2 and some of it reacts the carbon

unlike magnesium burning in CO2 which produces only carbon and Magnesium Oxide.

it seems like the more reactive group 1 elements form carbide easier.

direct combination of the elements seems like a better way
an idea for production comes to mind the reaction being preformed in a metal can. using graphite from a pencil. an electrical current causing the pencil lead to glow. the lithium metal would melt activated carbon will be covering the lithium metal on the surface while it is melting to prevent the oxygen from reacting with it. the lithium metal being wrapped around the graphite.

[Edited on 20-10-2011 by symboom]

ScienceSquirrel - 21-10-2011 at 03:43

Quote: Originally posted by symboom

that makes a whole lot more sense Li + CO2 --> LiO + Li2C2
i know unbalanced
but it cover the jest of the reaction as some of the lithium reacts with the oxygen from co2 and some of it reacts the carbon

unlike magnesium burning in CO2 which produces only carbon and Magnesium Oxide.

it seems like the more reactive group 1 elements form carbide easier.

direct combination of the elements seems like a better way
an idea for production comes to mind the reaction being preformed in a metal can. using graphite from a pencil. an electrical current causing the pencil lead to glow. the lithium metal would melt activated carbon will be covering the lithium metal on the surface while it is melting to prevent the oxygen from reacting with it. the lithium metal being wrapped around the graphite.

[Edited on 20-10-2011 by symboom]

To be honest that sounds like an excellent way to produce a small but deeply unpleasant fire.

bfesser - 21-10-2011 at 13:53

Without even looking at data, I'd guess that Li is a much better conductor than a graphite pencil lead. You'd effectively be shorting out your heat source. I do, however like your idea for obtaining high-temp from a graphite-based lead. Go with the softest grade you can get your hands on--it would have a lower proportion of clay to graphite.

Courtesy of Lambda-Eyde:
<a href="http://www.sciencemadness.org/talk/files.php?pid=224851&aid=16258">Structural Phase Transition in Li2C2</a>

[Edited on 10/21/11 by bfesser]

Panache - 23-10-2011 at 04:20

Neil, that reference is gold, nice find, any other treasures in your chest.

Neil - 24-10-2011 at 12:24

Thanks, nothing better; though this one is interesting, it doesn't make thermodynamic sense to me...

Attachment: 4137295_Carbide_production_using_molten.pdf (173kB)
This file has been downloaded 554 times

It does involve high pressure air, chlorine, molten lithium, acetylene, incandescent charcoal and molten iron so it sounds like a good stove top experiment.

Certainly much more feasible then the previously link stainless steel pot full of materials and low temperatures.

symboom - 30-10-2011 at 15:12

well i asked nurdrage since i was thinking about it after seeing his purposed page
http://sites.google.com/site/nurdrage/pr

stated by nurdrage
Re: making Lithium Carbide?
i was thinking of putting lithium metal with crushed aquarium activated charcoal in a metal tube and heating that to the melting point of lithium. Problem is ensuring safety. what i was told which i understand you don't what molten metal flying out. the thing is ive lit lithium in air it burns like magnesium. first kinda red then dazzling white.
http://www.youtube.com/watch?v=izSOC6stCT0&feature=relat...
ive done it before to really nice easier to light than magnesium with a lighter, but under co2 or carbon reaction im not to sure how it will react and if it will be volent or not.

[Edited on 30-10-2011 by symboom]

woelen - 30-10-2011 at 23:42

Quote: Originally posted by symboom

Li2C2 can also be prepared by reacting CO2 with molten lithium.
this one seems to be the easiest to achieve temperature wise.
which seems to make not very much since because magnesium burns in CO2 and forms magnesium oxide and carbon.this would be saying that the reaction is 2Li + CO2 -> Li2C2 + 2O2
[Edited on 10-10-2011 by symboom]

You should see at once that this reaction equation can NEVER be correct, and then I am not referring to the incorrect balancing. Even if you wrote

2Li + 2CO2 ---> Li2C2 + 2O2

you should see that this is utter nonsense. Do you really think that a strong oxidizer like O2 can be formed from a strong reductor and CO2? If a reaction occurs (which I can imagine at sufficiently high temperature) then the only thing which I can imagine which will form is Li2C2, Li2O and maybe some other lithium/carbon compounds and also possibly some CO and Li2CO3 in side reactions or secondary reactions. But no O2, never!

[Edited on 31-10-11 by woelen]

symboom - 31-10-2011 at 12:25

i already said i was wrong mistaking the reaction i figured it was wrong but didnt think what else formed along side the lithium carbide.

[Edited on 31-10-2011 by symboom]

low temp lithium carbide

bismuthate - 1-10-2013 at 03:04

i want to produce LiC by passing hydrogen over lithium in a test tube and gently heating it then after the litium hydride is formed i planto change the gas stream to acyteline which will react to form LiC. A quick search on wiki said that this could be done at room temp. i want to know if anyoe is intrested in this metod and how i could improve it.

WGTR - 1-10-2013 at 10:16

Well, for one thing, expect that the reaction between solid lithium and hydrogen will be very slow and incomplete unless the lithium is divided, and/or the gas is under pressure. Molten lithium reacts much faster, but it also reacts with glass, so a test tube isn't going to work for this.

There is already a lithium carbide thread here, along with references:
http://www.sciencemadness.org/talk/viewthread.php?tid=17734

Anyway, what is important to you? Conversion %? Selectivity? Low reaction temperature?

[Edited on 1-10-2013 by WGTR]

bismuthate - 1-10-2013 at 11:06

low temp that is the whole point of this thread, for a low temp synthesis . i plan to heat it in a silvered flask or a steel contained in a test tube with (decently) high pressure for quite a while.
I want to be able to do this without a blowtorch.
here is the link to the article which i got my info from.

http://en.wikipedia.org/wiki/Lithium_hydride
[Edited on 1-10-2013 by bismuthate]

[Edited on 1-10-2013 by bismuthate]

WGTR - 1-10-2013 at 14:17

OK. Looking at one of your other posts, I understand better that your resources for heating are rather limited. I understand the frustration in that. Still, that limitation makes this type of reaction awkward, because you're trading high temperature for pressurized hydrogen. I can't help but worry that you really don't have the equipment needed to safely perform the reaction the way that you want to do it. Maybe I'm misreading the situation.

Personally, I'd work at finding a heat source somehow. I built a portable furnace from four firebricks and a cpu fan. It runs on mesquite charcoal. That thing gets up to 850-900°C, and (with proper PPE) I use it safely on the front porch. With something like this you could directly combine lithium and carbon in a sealed tube. With about 28% argon (mole %, the rest being air), the pressure inside and outside of the tube should be the same at 800°C, so the tube shouldn't expand or collapse.

If you think this is something you could do, then I can try it when the weather cools off, to make sure it doesn't do something unexpected (the winter is when I play with the furnace).

That's really the best advice I can offer on this. Maybe someone else has better ideas.

bismuthate - 1-10-2013 at 14:59

I have an alcohol burner that i can use to heat the reation. The reaction will take a few hours i would guess, but it can take place at 29 degrees celcius, so it will work at 200 degrees too.
Another idea
If i can seal the hydrogen with powdered lithium in a sealed steel container and then place the contained on a Zn/MnO2 mixture and ignite it and repeat this multiple times it will fully react.
or i could heat the container over a course of days.
I apreciate your concern but my mom just will not let me use heat. (she is ok with most things just not heat or mercury )
i hope that i will get a blowtorch this year for christmass of something like that this would open so many doors for me. ( she doesn't allow fires either)

WGTR - 1-10-2013 at 16:37

By "alcohol burner", are you talking about a small jar of alcohol, with a wick in it?

Will your mom let you use...a reflector-type incandescent light bulb? Those can get some things pretty warm, and are made for continuous use. They are often used indoors for track lighting, and things like that.

Anyway, for the first try I'd recommend not using compressed hydrogen, but making a gas-bag from the common ordinary ziploc bag. You can run a hose from the bag through the tube stopper, and monitor the progress vs. time. If the reaction is proceeding at all, you should see the bag deflating. Hydrogen may leak from the bag over a period of days, so maybe an extra "control bag" will help you account for that.

bismuthate - 1-10-2013 at 16:46

i like the bag idea but will lithium corrode it?
yeah i got the burner from a chem 3000.

WGTR - 1-10-2013 at 17:11

The lithium remains in your reaction tube, hopefully; connected to the bag of hydrogen by a flexible hose. Although...if you're not planning on heating the reaction to more than 50C or so, maybe you can put a small "boat" containing your lithium entirely in the bag of hydrogen, and just heat up the whole bag.

To make the hose connection to a ziploc bag, I just poke a small hole into the side of the bag. This hole is just a bit smaller than the soft rubber hose, so that when the hose is pressed through, the bag stretches around it, giving a decent seal. Sometimes it takes a few tries, and it helps to tape the hose down to the bag. When it's finished, I'll fill the bag full of air, clamp off the hose, and check the seal by pressing gently on the bag. It shouldn't deflate.

The other end of your hose can connect to your hydrogen supply, or while the reaction is occurring, can be clamped off with a hemostat.

bismuthate - 1-10-2013 at 17:24

sounds good.
LiH has many other uses too.

bismuthate - 2-10-2013 at 09:17

i like that idea, but could i put aluminum foil and a sodium hydroxide solution in a small fire extinguisher with lithium in a dish suspended above it and wait for it to fill with hydrogen? Then i would seal the top and let the pressure build. after a few days I would open it up and retrive the lithium hydride. then i will repeat the process with calcium carbide and water.

WGTR - 2-10-2013 at 10:53

It's going to be hard to ensure that your hydrogen gas is dry in that case. Traces of moisture may speed the formation of lithium hydride the way that it does for nitride and oxides, but I think it's more likely that the lithium will react with the moisture faster than it does with the hydrogen, leaving you a mass of lithium hydroxide. But I don't know if this would be the case. That would be a project for you.

One useful resource is Leonid Lerner's book "Small-Scale Synthesis of Laboratory Reagents with Reaction Modeling", where he discusses the formation of lithium hydride (pg 73-79). I believe he goes by the name Len1 here on SM, if I remember correctly. It's a good book for explaining hands-on methods for preparing alkali metals, etc. The relevant parts may be available to you on Google books, if you search for it.

bismuthate - 2-10-2013 at 11:05

ok I can get rid of all moisture by using silica coating the walls ot the litium container with silica gel or CaCl. also water won't evaporate easily at high pressure.

AJKOER - 4-10-2013 at 17:01

OK, here is an extract of Atomistry.com (see http://lithium.atomistry.com/lithium_carbide.html ) on the preparation and some properties of C2Li2:

"The Lithium carbide, Li2C2 was first prepared by Moissan by the reduction of lithium carbonate with charcoal in the electric furnace -

Li2CO3+4C=Li2C2+3CO.

Tucker and Moody were unable to prepare the almost pure carbide described by Moissan, and attributed their failure to the very small temperature-interval between the formation and the decomposition of the substance. The carbide is also formed by the interaction of lithium and any of the allotropic modifications of carbon in vacuum at dull red heat; and by the combination of the metal with carbon monoxide or dioxide, or with ethylene or acetylene, an impure product is obtained.

Lithium carbide is a white or grey crystalline substance, its density at 18° C. being 1.65. At bright red heat it is decomposed, and Tucker and Moody found that at 925° C. and a pressure of fifty pounds to the square inch it absorbs nitrogen freely with formation of cyanamide, dicyanamide, and cyanide. It is a powerful reducer, decomposing water energetically at ordinary temperatures with formation of acetylene"

Also, on Lithium carbonate, to quote Atomistry.com (see http://lithium.atomistry.com/lithium_carbonate.html ):

"When heated below 1000° C. lithium carbonate undergoes partial decomposition into the oxide and carbon dioxide, a resemblance to calcium, but a distinction from sodium and potassium -

Li2CO3=Li2O+CO2"

And as:

Li2O + C --> 2 Li + CO or 2 Li2O + C --> 4 Li + CO2

it appears that C2Li2 may be formed as stated above "by the combination of the metal with carbon monoxide or dioxide". However, the source's comment to quote "an impure product is obtained" may also apply to the CO/CO2 path. If so, the reaction pathway may be more complex.

[EDIT] Interestingly, here is the reversible net reaction cited (see http://calcium.atomistry.com/calcium_carbide.html ) for the formation of Calcium carbide, CaC2:

CaO + 3C ⇔ CaC2 + CO

As such, I would not be surprised if the action of CO on Li, absence any O2, formed a mixed sample containing Li2O.

[Edited on 5-10-2013 by AJKOER]

bismuthate - 4-10-2013 at 17:59

Sounds great, but i can't use it because i wanted low heat.