Sciencemadness Discussion Board

CaC2 + H2O2 30% => BOOM ??

metalresearcher - 15-11-2011 at 13:10

I did not try it (too scared) but I am just curious what you think.
Performing such an experiment is rather dangerous.

Adding carbide powder to 30% peroxide will as I think release acetylene gas AND oxygen as a powdered material acts as a catalyst for decomposing H2O2.
So putting this in a closed plastic container and throwing it into a fire will explode ????

Mailinmypocket - 15-11-2011 at 14:29

As far as whether it would have a significant catalytic effect on the h2o2 I am not certain but if one was to simply add CaC2 to water in a bottle with water, and cap it tightly... It may possibly explode on its own not due to pressure (first anyways) but since acetylene decomposes explosively at elevated pressures... Interesting thought! I will try adding some calcium carbide powder to 35% h2o2 this evening and see if oxygen is released, without using a sealed container of any sort though.

PHILOU Zrealone - 16-11-2011 at 13:54

Since CaC2 is hardly chemically pure, since CaC2 reacts exothermically with water, since H2O2 is less stable in alcaline media...one might indeed expect degassing of O2 out of the H2O2.

Beware of the blast...acetylen/O2 is very powerfull...VOD is over 3km/s what is one of the fastest detonating gas-mix. A 100L plastic bag of the stoechiometric mix can blow a brick-wall appart just by standing next to it when detonated...what usually happens by static electricity!

White Yeti - 16-11-2011 at 14:36

That's not a good idea. Although you can get the BOOM you're looking for, you should try to control this in some way. The heat of the reaction, or just a spark, can set off a premature detonation.

I would rather fill a balloon with a stoichiometric amounts of oxygen and C2H2.

AndersHoveland - 17-11-2011 at 21:07

I actually tried this in a closed plastic bottle. There is no explosion (other than the bottle bursting). But after the bottle burst, I ignited the remaining gas inside the bottle, and there was a "boom" with a small flash fire ball (which did not burn my hand), and the bottle launced several meters into some bushes from the gas detonation.

Will CaC2 + H2O2 form explosive oxyacetylene ?

metalresearcher - 24-11-2013 at 03:05


Sorry I already posted this years ago, but saw it too late.
Sorry for the multi post.



First I am NOT going to try this as it is TOO DANGEROUS, but just a theoretical question.
Calcium carbide with water yields acetylene.
Decomposing of 30% Peroxide in water is catalyzed by grainy stuff like CaC2.
Combine both of them: generating C2H2 + O2 at the same time.
Putting CaC2 in a plastic bottle containing 30% H2O2 and closing it will result in a HEAVY EXPLOSION.
Is this true ?


[Edited on 2013-11-24 by metalresearcher]

bismuthate - 24-11-2013 at 07:22

Well I know that CaC2 is flammable and H2O2 is a strong oxidiser so I'm would think that mixing them could very well cause an explosion. That heat would decompose the remaining H2O2 and the remaining CaC2 would react with water forming C2H2 mixing with pure oxyegen, so ..... yeah. Not a good idea if it goes the way I predict.

vulture - 24-11-2013 at 15:09

Probably nothing is going to happen. The autoignition temperature of acetylene is listed as 350C, there's no way you're going to achieve that by simply dropping calcium carbide in 30% hydrogen peroxide.

Vikascoder - 26-11-2013 at 08:06

In 500 ml bottle I poured about 250 ml of 50% H202 . Then I added pieces of calcium carbide I don't have it in powder form . After some time the bottle bursted out due to decomposition of H202 and there was no fireball or any ignition of C2H2

bfesser - 26-11-2013 at 08:46

<a href="http://en.wikipedia.org/wiki/Acetylene#Safety_and_handling" target="_blank">
Quote:
[Acetylene] is also highly flammable (hence its use in welding). Its singular hazard is associated with its intrinsic instability, especially when it is pressurized. Samples of concentrated or pure acetylene can easily react in an addition-type reaction to form a number of products, typically benzene and/or vinylacetylene. These reactions are exothermic, and unlike other common flammables, do not require oxygen to proceed. <u>Consequently, acetylene can explode with extreme violence if the absolute pressure of the gas exceeds about 200 kPa (29 psi).</u> <img src="../scipics/_wiki.png" />
</a>

Fantasma4500 - 28-11-2013 at 08:19

in the matter of fact ive seen CaC2 + water in a plastic bottle being lit on fire
the author i spoke to explained that they wont blow up due to pressure as the reaction simply stops at a certain pressure within the limit of the plastic bottles
theres more than sufficient O2 in the bottle as C2H2 only needs 3% O2 to burn!!

he told me that putting something burning on the side of a bottle with hydrogen doesnt work as well as with acetylene, he had no successes with it, im quite sure it would work however..

also 75 25 H2 O2 will reach a VoD (guess it can be discussed whether its a legit detonation..?) of 4000 m/s

i have heard about 30 mL butane in a PVC bottle with some sparklers sticked to the side should give a decent bang aswell, not sure if this is legit.. could do so much more with 30 mL butane than that

seemingly to me hydrogen just burns even better with MORE hydrogen in a bottle, perhaps its sometimes mistaken for being too little? perhaps its just about luck? recently got 20 secs of ringing ears by hydrogen in a open bottle, ordinary 500 mL, it sure has potential