When base is added to mixture of bis(2,4,6-trichlorophenyl) oxalate, hydrogen peroxide, and a fluorescent dye, it glows blue. This is the type of reaction that is commonly used in commercial "lightsticks".
This demo can be used when discussing carbonyl chemistry in an organic chemistry course. This demo must be done in a room that can be darkened quite a bit. Allow about five minutes for this demo.
The hydroxide ion deprotonates hydrogen peroxide to form the hydroperoxide ion, which act as a nucleophile to displace one of the trichlorophenyl groups on the oxalate diester substrate forming a peroxyacid/ester intermediate. The peroxyacid group is then deprotonated and acts as a nucleophile to displace the second trichlorophenyl group in an intramolecular ring closing reaction to form a cyclic peroxide having the molecular formula C2O4. The cyclic peroxide decomposes to form two carbon dioxide molecules. When it decomposes, it activates the fluorescent dye, which glows blue. Arthur G. Mahan and Nicholas J. Turro. "A Facile and Effective Chemiluminescence Demonstration Experiment." Journal of Chemical Education, v.51, no.8 (Aug 1974): pp. 528-529. http://science.howstuffworks.com/light-stick4.htm
- A 200x25 mm test tube containing a mixture of 2 g of bis(2,4,6-trichlorophenyl) oxalate and 0.5 g of 9,10-diphenylanthracene in 35 mL of dibutylphthalate.
- A #4 stopper.
- A test tube stand. (A 250 mL Erlenmyer flask holds the test tube nicely and allows for good visibility.)
- A dropper bottle containing 30% hydrogen peroxide.
- A wash bottle containing 1 M sodium hydroxide.
- Chemical resistant gloves.
- Wearing gloves and goggles, add about 1 mL of 30% hydrogen peroxide to the test tube, stopper, and shake vigorously.
- Darken the room. The test tube does not glow.
- Turn the lights back on, add a couple of milliliters of 1M sodium hydroxide, stopper, and shake vigorously.
- Darken the room. After a few seconds the test tube should begin to glow with a blue light.
- Splash goggles and neoprene gloves should be worn during this demonstration.
- 30% hydrogen peroxide solution is a strong oxidizer. Avoid getting it on your skin or in your eyes. Wear goggles. If you do get it on your skin, wash thoroughly with soap and water. If you get it in your eyes, flush with water for 15 minutes and seek medical attention.
- 1 M sodium hydroxide is corrosive. Avoid getting it on your skin or in your eyes. Wear goggles. If you do get it on your skin, wash thoroughly with soap and water. If you get it in your eyes, flush with water for 15 minutes and seek medical attention.
Bis(2,4,6-trichlorophenyl) oxalate is rather expensive. Refer to the cited article for instructions to synthesize the compound.