Please advise what chemicals (powder + salts) can produce Ethylene or Acetylene Gas for Artificial Ripening of fruits in packed fruit boxes?

  • $\begingroup$ I have never heard about acetylene as fruit ripening agent, only about ethylene. $\endgroup$ – Poutnik Jul 6 '20 at 14:35
  • $\begingroup$ @Poutnik As an entry: en.wikipedia.org/wiki/Ethylene_as_a_plant_hormone $\endgroup$ – Buttonwood Jul 6 '20 at 14:42
  • $\begingroup$ @Buttonwood I do know about ethylene as a plant hormone, but the article does not contain the word acetylene. $\endgroup$ – Poutnik Jul 6 '20 at 14:45
  • $\begingroup$ @Poutnik Well ethylene is a naturally inducing ripening agent produced by plant hormones. Calcium carbide is an artificial ripening agent because it comes in contact with moisture to produce acetylene gas which has similar effects to the natural ripening agent, ethylene. See the additional note in my answer. $\endgroup$ – Nilay Ghosh Jul 6 '20 at 14:46
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    $\begingroup$ @Poutnik Gotcha, sorry I flipped the two. Yet both seem to be used extensively enough to justify a studies like «Comparative effects of acetylene and ethylene gas on initiation of banana ripening» (doi.org/10.1111/j.1744-7348.1982.tb00837.x), too. $\endgroup$ – Buttonwood Jul 6 '20 at 15:09

Acetylene is produced by any of three methods:

  1. by reaction of water with calcium carbide

$$\ce{CaC2 + 2H2O -> CH#CH + Ca(OH)2}$$

  1. by passage of a hydrocarbon through an electric arc

$$\ce{coal + H2 ->[\Delta] CH#CH + non-volatile salts}$$

  1. by partial combustion of methane with air or oxygen.

$$\ce{6CH4 + O2 ->[1500 ^\circ C] 2CH#CH + 2CO +10H2}$$

Note that the calcium carbide procedure is easily the most controllable reaction and hence it is favored for small commercial purposes. The other two methods are very drastic as well as expensive. Maintaining an electric arc at high temperature is no joke. Hence, they are called as industrial level methods. So, if you are trying to produce acetylene to use it as a ripening agent, the best reaction would be the one with calcium carbide.

In the Wikipedia article of ripening, it is written that:

Calcium carbide is also used in some countries for artificially ripening fruit. When calcium carbide comes in contact with moisture, it produces acetylene gas, which is similar in its effects to the natural ripening agent, ethylene. Acetylene accelerates the ripening process.

Ethylene is a naturally inducing ripening agent produced by plant hormones, so you don't have to worry about it.

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    $\begingroup$ I agree. Calcium Carbide is by far the easiest method $\endgroup$ – Waylander Jul 6 '20 at 14:16

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