TCPO, or bis(2,4,6-trichlorophenyl) oxalate, is a chemical used in some types of glow sticks and is a key chemical in many chemiluminescent reactions.
When combined with a fluorescent dye like 9,10-bis(phenylethynyl)anthracene, a solvent (such as diethyl phthalate), and a weak base (usually sodium acetate or sodium salicylate), and hydrogen peroxide, the mixture will start a chemiluminescent reaction to glow a fluorescent green color.
Red, yellow and blue colors can be made by replacing the 9,10-bis(phenylethynyl)anthracene with rhodamine B, rubrene and 9,10-diphenylanthracene respectively.
The above fluorescent dyes absorb much of the energy produced during the decomposition of the oxalate ester, and convert that energy into light energy which is observed as the characteristic glow in products such as glowsticks.
TCPO can be prepared from a solution of 2,4,6-trichlorophenol in dry toluene by reaction with oxalyl chloride in the presence of a base such as triethylamine. This method produces crude TCPO with a by-product of triethylamine hydrochloride. The product is washed with water to remove the byproduct and recrystallized from toluene.