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Vexing
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Acetylene Synth
Anyway, is there any way to synthesize acetylene without a 2000 degree furnace or a carbide salt?
Calcium Carbide is very hard to get here, and I don't have an arc furnace. 
\"For every action there is an equal and opposite government program.\"
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tr41414
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Hmm... carbide must be out there (just go asking around in hardware-shop, say you have an old acetylene torch or a cave exploring lamp)...
There was also a "thermite" reaction described somewhere, CaO and C were mixed and ignited using car battery to yield CaC2... Dunno if it works... It
is also made by cracking various hydrocarbons, but it will be probably impossible to separate the products...
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roamingnome
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Relatively large amounts of acetylene (C2H2) are also produced......
http://www.scs.uiuc.edu/suslick/britannica.html
sonochemistry good for degrading stuff for sure.....
but acetlyene is so common its like asking to make sand ..well go to the beach
or in the case of acetylene a welding setup is handy for welding, oxygen, and your molecule of interst....
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chemkid
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I have some tubes of calcium carbide for a little metal canno (about three) The cannon is very old so i am not sure if the company still exists. Is
calcium carbide the same stuff a thermite or close to it?
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not_important
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| Quote: | Originally posted by chemkid
I have some tubes of calcium carbide for a little metal canno (about three) The cannon is very old so i am not sure if the company still exists. Is
calcium carbide the same stuff a thermite or close to it? |
Nowhere near. Thermites are self-contained redox systems, as in 2Al + Fe2O3 => Al2O3 + 2 Fe + lotso heat
Calcium carbide reacts with water to give calcium oxide or hydroxide and some heat
CaC2 + H2O => CaO + C2H2
CaO + H2O => Ca(OH)2
The cannon allows the acetylene to mix with some air in the cannon barrel to form an explosive mixture, then sets it off with a spark - all standard
combustion stuff. You can do the same thing with bottled gas (propane/butane) http://www.spudtech.com/content.asp?id=5
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12AX7
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Acetylene is also produced by cracking, steam or catalytic, isn't it? (Along with every other -ane, -ene and -yne imaginable...)
Tim
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not_important
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| Quote: | Originally posted by 12AX7
Acetylene is also produced by cracking, steam or catalytic, isn't it? (Along with every other -ane, -ene and -yne imaginable...)
Tim |
Yes, but it's another high temperature process - mid 700s to high 800s C, followed by rapid quenching with a water spray.
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jimmyboy
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Here is something interesting -- but wouldn't the arc ignite the hydrogen? maybe pure H2 isn't flammable..
In 1859, Marcel Morren successfully generated acetylene when he used carbon electrodes to strike an electric arc in an atmosphere of hydrogen. The
electric arc tore carbon atoms away from the electrodes and bonded them with hydrogen atoms to form acetylene molecules. He called this gas carbonized
hydrogen.
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Vexing
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Would burning carbon in pure hydrogen work too?
Burning carbon with CaO sounds easy, but thats how they do it industrially. Lime+Coke in an arc furnace. Would it take the same amount of heat or
would the reaction be self-sustaining?
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12AX7
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I wonder what the yields of benzene are in these methods.
Tim
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garage chemist
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I was long under the impression that carbide was impossible to get here, until I found out that technical grade carbide is completely OTC as a product
against rodents- a spoonful of it is put into their holes, and the acetylene generated contains PH3 and H2S and makes the rodents leave the place
vecause of the bad smell.
That was my first carbide I got.
Later I found several sources on the net, some of it much cheaper.
Carbide can be found everywhere, you just have to ask because only few people still need it. Saying that you need it for a carbide lamp in a sports
store is probably the best idea, I'm sure they can tell you where to find it.
If you really cant find carbide (which is very improbable), an acetylene gas tank for welding is the next best thing you can get.
Dont bother with any methods of making carbide or acetylene yourself, I've tried it myself with CaO+C and even a 2kW arc from a MOT did not produce
any reaction inside the mix.
Carbide is very cheap if you have the right source.
Do you want it for silver acetylide?
[Edited on 6-6-2007 by garage chemist]
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Vexing
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I want it for Silver Acetylide, Copper Acetylide, and as fuel.
Thanks garage chemist, I'll look around this weekend.
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chemoleo
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Garage chemist, now, looks like you haven't tried hard enough!
YOu can make it yourself, but at risk of blowing the house fuse - personal experience
https://sciencemadness.org/talk/viewthread.php?tid=2492&...
| Quote: | However, it is entirely possible to make it with an arc furnace.... that is, because I made it myself!
Quite simple really, miix the correct amounts of CaO and C, and subject them right into the arc.
You willl get chunks of solid stuff - and these chunks, when put into water, produce a flammable gas, that burn with a small pop and a yellow flame.
If you want I can tell u more.
I did this a long time ago, and I always meant to take pictures (this was before the digital age) just to document the process. It seriously isnt that
hard. I got about 2 g worth, in a matter of 15 seconds (I stopped, or got stopped because of the power failing.... seemed like I took more than 16
Amp/230 V out of the power grid. Basically, the automatic power fuse shut down, for the whole house. and 230V * 16Amp = ~ 4kW is about the max it
seems. |
The crucible was the size of a film canister, in a fire cement container, with two carbon rods used for welding sticking into the center. This
contacted more or less directly the CaO/C mix. Within the short period of time, it actually as sufficient to melt the surrounding fire cement! Scary
experiment, particularly to do this inside!
Never Stop to Begin, and Never Begin to Stop...
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Mr. Wizard
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chemoleo, Your production of calcium carbide sounds interesting. No doubt you did draw the mains too much. The resistance of the arc and the 'melt'
goes down once the heat goes up, presenting less of a resistance to the mains. It goes essentially to a short circuit, which will blow a breaker or
fuse. There are ways to prevent this. First you could put enough of the units in series to add up the voltage drops to the main voltage. This would be
tricky. Second you could use a step down transformer such as a welder to more closely match the high current load. This is the most expensive option.
The easiest would be to introduce some sort of current limiting device such as a large light bulb. You could put two or three (cheap) 500 watt quartz
halide lamps in parallel and then put them in series with your electric furnace. The total load to the mains will never be more than what the lamps
alone would draw. You could even use switches to add or subtract resistance to the furnace. Most common wall switches here in the US will easily
handle 20 amps at 120 volts, and higher amperage ones are available. You could start the furnace on one 500 watt bulb, and then as you watched the
progress, you could add more current by adding more lamps in parallel, up to the limit in watts of your circuit.
Don't stay too close to the lights, they give off a lot of UV.
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chemoleo
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THat's good advice, I like the lightbulb idea.
From what I found, welders aren't actually that expensive, I wonder why noone tried using that? I used a dedicated transformer, at 42V/4kW. Welders
are betw 20-30V, the arc might not be as long but it should still work, right?
One problem I had at the time was swtiching off the transformer at high load - the induction upon switching off would induce currents back into the
system, causing again the mains to drop out... but I seem to remember having addressed this somewhere years ago...
Never Stop to Begin, and Never Begin to Stop...
Tolerance is good. But not with the intolerant! (Wilhelm Busch)
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12AX7
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Don't you guys have lots of GFCI, like federally? Around here, it's only required within 5' (~1.5 m) of water and fixtures. It shouldn't be tripped
except for, well yeah exactly that, a ground fault per se, but heavy sparks like that probably could make trouble. Of course, running more amperage
than your circuit is rated tends to trip its breaker, too.
Tim
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Aqua_Fortis_100%
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| Quote: | Originally posted by garage chemist:
I was long under the impression that carbide was impossible to get here, until I found out that technical grade carbide is completely OTC as a product
against rodents- a spoonful of it is put into their holes, and the acetylene generated contains PH3 and H2S and makes the rodents leave the place
vecause of the bad smell.
That was my first carbide I got.
Later I found several sources on the net, some of it much cheaper. |
Yeah! CaC<sub>2</sub> is a great OTC chemical.. look around in local welding stores and places where the people sell industrial gases or
so (actually i think which this is a ideal source because the acetylene come in PURE form, against the acetylene produced directly by calcium carbide
, which contain lots of impurities as garage chemist says).
Some years ago, i've used for acetylides.. in first times i've used the direct gas going out of CaC<sub>2</sub> + water, but i found a
procedure where the gas is somewhat purified by bubbling it in aqueous NaOH solution and washing for remove NaOH content, bubbling in some fresh
water,and then in the desired solution to ppt out the acetylide..
i tried this new one and seemed to work wonderfully (the NaOH solution, over some time of operation and plus more time standing "in peace", forms a
fine suspension of a brown/black/reddish precipitate which fall in the bottom).. i dont know well the solubility of phosphide and sulfide salts, but
i'm think which is somewhat good..which in turn leave me to consider that probably another kinds of impurity comes in the *crude*
C<sub>2</sub>H<sub>2</sub> ... and i really don't know what are these nasty stuffs.. (note which this is only a
observation/speculation..no mean which is right..)
look my poor drawing below...
(for tubes i've used aquarium ones, for sealant the hot glue and for bottles the old know and free PET bottles  )
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Vexing
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In KABOOM's post about the Kolbe reaction (link: https://sciencemadness.org/talk/viewthread.php?tid=1050&...) , he mentions that maleic and fumaric acid and their salts (in solution) can be
changed into acetylene, CO<sub>2</sub> and carbon monoxide by electrolyzing them. Has anybody tried this?
Here (http://jagor.srce.hr/ccacaa/CCA-PDF/cca2002/v75-n1/CCA_75_20...) it says that the yield for fumaric acid is between 23 and 31% acetylene, the
yield for maleic acid is lower.
I don't have any fumaric or maleic acid, so I can't do it.Is there an OTC source for these?
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Jdurg
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| Quote: | Originally posted by jimmyboy
Here is something interesting -- but wouldn't the arc ignite the hydrogen? maybe pure H2 isn't flammable..
In 1859, Marcel Morren successfully generated acetylene when he used carbon electrodes to strike an electric arc in an atmosphere of hydrogen. The
electric arc tore carbon atoms away from the electrodes and bonded them with hydrogen atoms to form acetylene molecules. He called this gas carbonized
hydrogen. |
What exactly would the hydrogen combine with if it was in a pure atmosphere of H2. ALL gases are not flammable if you don't have an oxidizer to
complete the combustion. Take a balloon of H2 gas and put it in a dry-box filled with argon. Try igniting the H2 gas. It never will ignite. Now
replace the argon with oxygen and ignite it. It will ignite instantly.
In the reaction you are describing, there was absolutely no oxygen available to react with the hydrogen, therefore it did not combust.
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symboom
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Acetylene gas from Ethanol
Acetylene from ethanol
This should help the OP in not needing to create
Calcium carbide to make acetylene this
Reagents
Ethanol
Aluminum oxide/or sulfuric acid
Bromine
Intermediates created in reaction and used
ethylene
1,2-dibromoethane
A fairly rapid stream of ethylene is generated from ethyl alcohol and sulfuric or phosphoric acid. The ethylene gas is washed first with water and
then with dilute solution of sodium hydroxide, is passed into 100 g of bromine contained in a glass flask cooled ice-waters. The stream of ethylene
gas is continued until the brown color of bromine disappears. The 1,2-dibromoethane forms as an oily liquid which is washed with dilute solution of
sodium hydroxide, dried with calcium chloride. 1,2-dibromoethane is purified by distillation yielding colorless oily liquid, freezing at 8° C and
boiling at 131° C.
Preparation of bromine
http://www.sciencemadness.org/talk/viewthread.php?tid=72804&...
This is for iodine but it works for bromine
https://m.youtube.com/watch?v=lrwa5x5bTCE
Solid iodine can easily be made by an oxidation reaction between potassium iodide and a persulfate salt (ammonium in this example). The reagents react
directly with stirring to form solid iodine. This process also works on bromides to create liquid bromine if the solutions are concentrated enough
Bromine preparation as a solution in DCM
For chem players process oxone could be used
https://m.youtube.com/watch?v=Au2Hb6XKohE
My method is to use potassium peroxymonopersulfate(oxone)
And sodium bromide both are pool chemicals sodium bromide is for spas and oxone is non chlorine shock
Electrolytic Bromine pt 1 from sodium bromide
https://m.youtube.com/watch?v=NKjyM2AkZSY
Electrolytic Bromine pt 2
https://m.youtube.com/watch?v=orFf-l0s1bc
Preparation of acetylene from 1,2-dibromoethane and potassium hydroxide
100 ml of rectified ethanol and 25 g of powdered potassium hydroxide are placed in the flask F. The mixture is gently boiled under reflux until the
potassium hydroxide is almost entirely dissolved. 15 ml (or 33 g) of 1,2-dibromoethane is place in the dropping funnel D, and added drop-wise into the
boiling solution of potassium hydroxide in ethanol. A rapid reaction occurs, acetylene being generated and potassium bromide precipitated. Generated
acetylene is passes through the apparatus until all the air is expelled. Then acetylene is collected under water or directly used for an experiment.
__________________________
Videos and their procedures
How to Make Aluminum Oxide
https://m.youtube.com/watch?v=Vr1m9d9e8YY
How to Make Ethene (Ethylene) - Catalytic Dehydration of Ethanol
https://m.youtube.com/watch?v=I-10WJ_t4NQ
Ethene can be produced by dehydrating ethanol (removing a water molecule). Aluminum oxide catalystis used to catalyze the dehydration of ethanol.
1,2-dibromoethane to acetylene
https://m.youtube.com/watch?v=mVgxMhDysUg
Ethyne can be prepared from ethylene bromide by dehalogenation as well as dehydrohalogenation .
Dehalogenation is the removal of halogen from a compound for example ethylene dibromide on reaction with zinc gives ethyne .
Dehydrohalogenation is removal of hydrogen and halogen from a compound . It occurs in presence of alcholic KOH .
ethylene dibromide and zinc is used to produce ethyne gas and collect it with downward displacement of water
___________________________
Storage of acetylene gas in solid compound
Option 1
Acetylene-cuprous aluminum tetrachloride
https://www.google.com/patents/US3647843
Patent US3647843 -
Cuprous aluminum tetrachloride complexes with acetylene
Option 2
Lithium acetylide amine complexes
https://www.google.com/patents/US3234284
Option 3
The Preparation of Lithium Acetylide-Ethylenediamine
http://pubs.acs.org/doi/abs/10.1021/jo01045a069?journalCode=...
Option 4
Lithium acetylide
http://www.prepchem.com/synthesis-lithium-acetylide/
Option 5
http://www.sciencemadness.org/smwiki/index.php/Acetylene
A new method was developed in 2009, where acetone is stored in a metal-organic framework (MOF), a lattice-like structure made of copper oxide and
benzene
Gas-phase reactions of copper atoms: formation of copper dicarbonyl, bis(acetylene)copper, and bis(ethylene)copper
http://pubs.acs.org/doi/abs/10.1021/j100175a055
Acetylene may be produced in reverse applications of which it is used such as acetylene in the making vinyl
Such as PVC to acetylene by depolymerization and dechlorinization
Or acrylic although I have not found and experiments to which someone has done this.
And just realized BB code would have made my post look better should have read the FAQ of the site would have made life easier
[Edited on 18-6-2017 by symboom]
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Tdep
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Hey really interesting post there symboom, seems like a cool way to make acetylene if one had lots of Br or I. And you could just make lots of the
1,2-dibromoethane intermediate because storage doesn't look that hard. Low vapour pressure, and freezing point around 10 degrees C, you could just
keep it indefinitely in a (non-food) fridge without any loses.
I just wanted to pull you up on this. Firstly, the complex is between Cu(2+) (you can use any copper(2+) source, copper oxide does work but it's nicer
to use a soluble copper source like the nitrate) and 1,3,5-benzene tricarboxylic acid (trimesic acid) not benzene. I'll correct it on the Wiki if I
can.
If anyone wants to know more about this, MOFs are the area I currently do research in. They are really interesting nanomaterials that 'self assemble'
into framework structures with pore channels that allow interesting chemistry and physical interactions like gas absorption (because they're a
lattice, the 'surface area' of these materials is unimaginably high) or gas filtering (where the pore size can act like a net, separating them out
physically or chemically) or a whole lot of other applications from capacitors to drug delivery to exotic catalysis to waste treatment. New MOF papers
come out daily at the moment. Many are readily accessible to the ameatur (some are too easy!) and if people want to see me make any youtube videos on
it, I can do that maybe. Anyway, I wont drone on too much.
Copper and Trimesic acid make the framework structure named HKUST-1 (they often get named after the place that discovers them, in this case it's Hong
Kong University of Science and Technology) and while it's perhaps one of the most studied frameworks (because it's rad) but does have its issues,
especially in what your proposing here, for storage of acetylene.
While HKUST-1 does have very high uptake of gases such as carbon dioxide and acetylene, this is largely due to coordinately unsaturated metal sites on
the copper. This means the gases bind very readily, but are difficult to release. So many papers claim 'hey look at how great HKUST-1 is at stripping
carbon dioxide out of air/flue gas ect.' but if it's incredibly energy intensive to re-release the gases again, it's more harm then good. So not sure
how easy it would be to get back your acetylene.
The major issue with HKUST-1 is that it's unstable to water. This is the reason you haven't actually seen it in real life, despite it being promising
in a huge number of applications. Exposure to ambient air does destroy the structure. If you wanna pump acetlyene into it, sure, but it has gotta be
dry.
Lastly: Passing acetlyene into a copper framework? Dear god, that does not sound safe to me. Copper acetlyides are very sensitive explosives. Sure,
maybe it wont form because there's only copper(2+), but as the framework breaks down, or you haven't cleaned the pores of the materials enough... MOFs
are good but Copper and acetylene is not a good combo for me.
(sorry for long post, procrastinating assignment)
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AJKOER
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Yes, I read about this in an old text concerning electrosynthesis! My recollection was the use of Pt electrodes.
Here is a more recent source, see comments about a Kolbe electrolysis at https://www.scribd.com/doc/61907186/Maleic-and-Fumaric-Acid .
[Edited on 18-6-2017 by AJKOER]
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symboom
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Thank you Tdep I spent hours on research for an acetylene synthesis and storage. I really want to see amature chemistry flourish. There has already
great achievements such as sodium metal, phosphourous production, and hydrazine. No problem about your post with regards to the use of copper as a
metal framework copper acetylide is a great storage for acetylene releases acetylene when HCl is added unfortunately it is explosive
The one of interest ro me is the Cuprous aluminum tetrachloride complex I dont think it is explosive and from what I read it is more stable
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Dan Vizine
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Quote: Originally posted by Tdep  |
Lastly: Passing acetlyene into a copper framework? Dear god, that does not sound safe to me. Copper acetlyides are very sensitive explosives. Sure,
maybe it wont form because there's only copper(2+), but as the framework breaks down, or you haven't cleaned the pores of the materials enough... MOFs
are good but Copper and acetylene is not a good combo for me.
(sorry for long post, procrastinating assignment) |
His (ill-advised) intention is to make Ag & Cu acetylides!
"All Your Children Are Poor Unfortunate Victims of Lies You Believe, a Plague Upon Your Ignorance that Keeps the Youth from the Truth They
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symboom
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| Quote: Originally posted by Dan Vizine | | Quote: Originally posted by Tdep |
Lastly: Passing acetlyene into a copper framework? Dear god, that does not sound safe to me. Copper acetlyides are very sensitive explosives. Sure,
maybe it wont form because there's only copper(2+), but as the framework breaks down, or you haven't cleaned the pores of the materials enough... MOFs
are good but Copper and acetylene is not a good combo for me.
(sorry for long post, procrastinating assignment) |
His (ill-advised) intention is to make Ag & Cu acetylides! |
No I dont want to make coppper or silver
acetylides I would perfer it in a less dangerous salt like iron or if the aluminum coppper complex is not dangerous that would be great acetylene is
useful for making oxalates and formic acid that is what the patent says not mine. You misnderstand me many people cant get calcium carbide (already
have :-))for acetylene. it is an extremely great fuel the problem copper attaches to the acetylene and is released with an acid producing acetylene it
sucks that copper acetylene is dangerous im talking about storage great if I didnt have to buy acetylene everytime I run out and oxygen not cheap
But im more interested in the process and seeing if it can be done I would rather avoid using copper but I think the copper aluminum complex as
stated from the patent
like of oxy acetylene welding my first introduction into welding smooth and really hot. Also the boom stands for boom box music is what I like It has
helped me think of a name
Whos ready for welding with vodka (acetylene from vodka)
Acetylene the third worlds hottest flame
[Edited on 23-6-2017 by symboom]
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