MadSci Network: Chemistry

Re: Chemical Light / Using Peroxide and Ester

Area: Chemistry
Posted By: Jeremy Starr, Grad Student, Chemistry, California Institute of Technology
Date: Sat Sep 13 14:06:49 1997
Area of science: Chemistry
ID: 873009376.Ch
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!


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