|MadSci Network: Chemistry|
Hi Ed, Thanks for your question. "Ester" is a general term for any compound containing an ester group, but, by itself, the term does not refer to any particular compound. Also, "peroxide" is a general term for any compound containing a peroxide group although hydrogen peroxide is sometimes called just "peroxide". Unfortunately, I was unable to find an example of a simple light producing reaction involving a peroxide and an ester. (However it is possible that one may exist). The light produced by fireflies is generated when a type of enzyme called a "lucefirase" is activated by one molecule of ATP (Adenosine TriPhosphate). That complex then binds to a molecule of "luciferin" and the enzyme then transfers a part of ATP called AMP (Adenosine MonoPhosphate) to the luciferin. This modified luciferin molecule then reacts with ordinary molecular oxygen (from air presumably) to form a compound containing a cyclic endoperoxide group. The cyclic endoperoxide decomposes spontaneously to give carbon dioxide and a new derivative of luciferin called "decarboxyketoluciferin". When this occurs the product is in an electronically excited state which must release a photon of light to return to its desired ground state. The photon of light is what is observed as the light of the firefly. There are other reactions which are not related to the biological generation of light which would mimic the kind of luminescence generated by fireflies. One such reaction is that of "luminol" with oxygen (or other oxidizing agent) in the presence of a base (such as potassium hydroxide). The product is a cyclic endoperoxide (however structurally different from the cyclic endoperoxide in the case of fireflies) which decomposes to form an electronically excited product that releases light as it relaxes into its ground state. Unfortunately, this reaction and others like it would not be suitable for demonstration to your kids outside of a laboratory setting. In fact, the luminol experiment is frequently part of the laboratory curriculum for an undergraduate course in organic chemistry. One light emitting reaction I know that you and your kids could enjoy anywhere is chewing of peppermint lifesavers. If you chew the lifesavers while looking in your bathroom mirror with the lights out you should see a faint bluish light come off of the pieces as you bite them. I hope some of this information was helpful! Jeremy.
Try the links in the MadSci Library for more information on Chemistry.
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