Diacetylene in Space

Diacetylene, C₄H₂, has previously been discovered in the atmosphere of Titan and on the Moon. Polish scientists have recently observed it in translucent interstellar clouds.

The density of translucent interstellar clouds is extremely small, much less than the best vacuum we can produce in a laboratory, but because they are huge in size their gas molecules have a chance to interact with penetrating radiation, so scientists can use spectroscopy to study the composition of these translucent interstellar clouds.

Molecules absorb and emit photons of specific energies, and therefore wavelengths, corresponding to the differences between energy levels in their atomic structure. The light from stars that reaches the Earth is slightly changed as a result of interactions with gas particles in translucent clouds, it lacks the wavelengths absorbed by intervening interstellar atoms and molecules. Until now, compounds composed of no more than a few atoms have been found in these clouds, molecules such as C₃ andH₃⁺. It is possible that diacetylene is quite a common component of the interstellar medium, having now been located in two carbon-rich galaxy regions and in the averaged data coming from a dozen other lines of sight.

Reference
Institute of Physical Chemistry of the Polish Academy of Sciences (2010, September 17). Surprisingly complicated molecule found in outer space. ScienceDaily. Retrieved September 18, 2010, from http://www.sciencedaily.com­ /releases/2010/09/100915084456.htm

Further Reading
Spectroscopy : http://www.ausetute.com.au/spectros.html
Nomenclature : http://www.ausetute.com.au/namctut1.html
Alkynes : http://www.ausetute.com.au/namsynes.html

Study Questions:

1. Draw the structural formula for diacetylene, C₄H₂.
2. Give the systematic IUPAC name for diacetylene.
3. To which homologous series does the diacetylene molecule belong?
4. Give the empirical formula for the diacetylene molecule.
   
5. Is diacetylene an example of a saturated or unsaturated hydrocarbon? Explain your answer.
6. In Titan's atmosphere, diacetylene could be produced from the reaction between acetylene, C₂H₂, and the ethynyl radical C₂H. Write a possible chemical equation to represent this reaction.
7. Would you expect diacetylene to react with bromine water? Explain your answer.
8. Would you expect diacetylene to be easily oxidized? Explain your answer.