first let me say i know i can just buy calcium carbide but I just like to make chemicals , just to see if I can do it, and to see what I can learn
along the way as for acetylene i already do have it for welding so that is not the case. just to try it.
so Ive read calcium can be made from calcium chloride forming carbon dioxide at the anode with a carbon anode
basically CaO --> Ca + O
i know calcium will be made but will it combine with the carbon at the temperature of molten CaCl2
so to make calcium carbide
calcium oxide and carbon dissolved in molten calcium chloride
having molten calcium chloride is not a problem with my Fresnel lens as long as the sun is out
an arc furnace uses to much electricity from my wind turbine. it only puts out 600w redox - 25-4-2011 at 08:40
The internet says calcium chloride melts at 772 degrees C, and calcium carbide forms from union of the elements at around 2000 degrees C. It probably
won't work, but if you have the means, give it a try! Report back!IrC - 25-4-2011 at 12:51
Just an FYI but I would keep in mind in both your experiments if done in open air you are also likely creating at least a small amount of calcium
cyanide. m1tanker78 - 29-4-2011 at 13:23
I've tried this before in an arc furnace as well as directly placing the reactants near the very hot arc. My problem was that my 'refractory' always
melted before I got any appreciable carbide yields. Without suitable refractory, I gave it up.
Remember that you not only need very high temps, you also need to give it ample TIME which means constantly babysitting the electrode spacing.bbartlog - 1-5-2011 at 17:56
Quote:
having molten calcium chloride is not a problem with my Fresnel lens
You have a solar furnace that can reach 800C in an appreciable volume?symboom - 1-5-2011 at 18:55
i got a Fresnel lens one from here http://greenpowerscience.com/FRESNELSHOP/65INCHSPOT.html
they probably have some on ebay too
heard of people even getting them out of a crt monitor or a old tv crt type have a Fresnel lens in them too they are very helpful for heating and
dangerously powerful ie lights wood on fire in seconds
[Edited on 2-5-2011 by symboom]AJKOER - 26-5-2011 at 07:16
Here is a thought. Focus on a double replacement reaction using something that is easier to produce but perhaps more expensive.
As CaC2 is a so-called acetylide (or a percarbide), you might suspect success with a similar percarbide, perhaps Na2C2, Sodium Percarbide. Note,
Magnesium may also produce a percarbide but I know it makes a sesquicarbide, namely, Mg2C3, which may not work in our double replacement reaction.
Percarbides are generally made from the Alkaline and Alkaline Earth metals.
So possible reactions are (depending on the methods for making Na2C2 in the 1st step):
2 Na + 2 C --> Na2C2
Na2O + 3 C --> CO + Na2C2
Then:
Na2C2 + CaCl2 --> 2 NaCl + CaC2
This two step process is at least theoretically interesting and may proceed at much lower individual temperatures. More precisely, this process
involves the heat of formation of Na2C2 plus (CaC2 + NaCl), which is also an incremental stepwise process aside from the heat of formation relating
to NaCl.
Downside is the cost of the sodium salts, time to prepare the Na2C2, and not to mention, the possible separation issues to acquire pure CaC2.
[Edited on 26-5-2011 by AJKOER]symboom - 26-5-2011 at 11:21
AJKOER
thank you that reaction seems like it would work
Na2C2 + CaCl2 --> 2 NaCl + CaC2
as calcium chloride melts at 600C then the sodium carbide could react with it the sodium chloride would disolve in it living calcium carbide
also what temperature does sodium and carbon combine at
or sodium oxide and carbon.
2 Na + 2 C --> Na2C2
Na2O + 3 C --> CO + Na2C2
like lithium could this be done with sodium. To prepare pure samples in the laboratory molten lithium + graphite are reacted at high temperature.
(what temp) Li2C2 can also be prepared by reacting CO2 with molten lithium. It is reactive and hydrolyses very readily to form acetylene gas, C2H2,
and LiOH.
This is a reference on Wiki. One of the last edits was by "A Little Chemists" who could be someone who knows what he is talking about (or a kid,
hence 'little'). The most interesting speculated reaction is of Na in acetylene:
C2H2+2Na=Na2C2+H2
His quoted temperature for the production of sodium carbide, per the reaction below, is 1500C(?).
Na2O+3C=Na2C2+CO
This compares to the classic Calcium Carbide arc furnace that targets a working temperature of 2100C employing a stream of CO loaded coke and finely
powdered lime. Below 1630C, the reaction tends to be reversed.
"There is very little evidence of the direct formation of sodium carbide from the elements (29,30), but sodium and graphite form lamellar
intercalation compounds (16,31–33). At 500–700C, sodium and sodium carbonate produce the carbide, Na2C2; above 700C, free carbon is also formed
(34). Sodium reacts with carbon monoxide to give sodium carbide (34), and with acetylene to give sodium acetylide, NaHC2, and sodium carbide (disodium
acetylide), Na2C2 (see CARBIDES, CEMENTED) (8)"
I also can across a reference (Concise Encyclopedia Chemistry by DeGruyter, page 161) that states "Many metal oxides react with CaC2 to form
corresponding metals or metal carbides". If true for Ca, there is hope for Na and as such, the wild idea of a double replacement reaction may in fact
work. But, the temperature may be an issue as per the same source on page 7:
"The chloride is also reduced by calcium carbide at 800–1200C under vacuum (52).
2 NaCl + CaC2 --> 2C + CaCl2 + Na "
So our double replacement reaction starts to reverse itself in a vacuum at 800C and the melting point of CaCl2 is 782C! Therefore, as soon as the
CaCl2 melts, the temperature should be stabilized for hope of success.
FYI, Lithium Nitride decomposes between 840C and 850C, so it must be formed below 840C.
[Edited on 26-5-2011 by AJKOER]
[Edited on 26-5-2011 by AJKOER]
[Edited on 27-5-2011 by AJKOER]symboom - 27-5-2011 at 09:41
thank you AJKOER that is informative
ill try sodium and sodium carbonate that produce the carbide, Na2C2; above 700C, free carbon is also formed
i can reach around that temp of molten calcium chloride 782 °C (anhydrous)
Sodium reacts with carbon monoxide to give sodium carbide another interesting reaction
2Na + 2CO --> O2 + Na2C2
but what temperature is required for this reaction to take place
i have some sodium metal made from molten sodium hydroxide so these reactions would work
lithium carbide
Lithium Nitride decomposes between 840C and 850C, so it must be formed below 840C.
what did you mean by this?
reacting CO2 with molten lithium at 356.97 °F lithium is molten dry ice or paint ball co2 tank.also seems like an idea my main objective is acetylene
which i would rather make than buy CaC2 i have a bit of lithium from batteries.
the sodium is a lot cheaper to make. than buying lithium batteries
[Edited on 27-5-2011 by symboom]AJKOER - 28-5-2011 at 06:40
The link I gave has, as its reference, a US Patent 2642347 dated June 16, 1953 by H.W. Gilbert for the production of Sodium Percarbide, Na2C2. Try the
link below:
I was able read the 1st page. The reaction is actually between C and Na2CO3 between 1050C and 1200C. This produces CO and Na vapor, which is rapidly
cooled to between 625C to 780C (by a surface contact) to produce the highest yield. The chemical reaction is:
4 Na (g) + 3 CO (g) --> Na2C2 + Na2CO3
FYI, there is an older German Patent 526627 that involves Na and C to produce Na2C2.
Note, any of the percarbides (Sodium, Potassium, Calcium, Lithium,., ), also called acetylides, will react with water to produce acetylene.
