Ask A Scientist Chemistry Archive

(Created prior to 1993)

It is a common practice in the welding industry to store acetylene 
in acetone.  What chemical property causes the acetylene to be safer when 
stored in this fashion?  Why does dissolving acetylene in acetone make it less 
likely to explode?  Why, even dissolved, can the acetylene explode under 
certain circumstances?  Why does not it explode as it is exiting the acetone 
solvent, i.e. in the top of the tank?
Joe Schultz
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Acetylene burns in air readily, and is most safely hand-
led/stored in cylinders filled with crushed firebrick wet with acetone.  
Acetylene happens to dissolve readily into acetone, and the dissolved gas is 
no longer in contact with gaseous O2 (which does not tend to dissolve in 
acetone) and therefore is not as prone to decomposition by O2.  The firebrick 
also helps by minimizing the free volume of the cylinder, cooling and 
controlling any thermal decomposition before it gets out of control (each 
decomposition of acetylene gives off heat).
Topper
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