Diphenyl oxalate
Diphenyl oxalate (trademark name Cyalume) is a liquid ester whose oxidation products are responsible for the chemiluminescence in a glowstick.[1] It can be synthesized by fully esterifying phenol with oxalic acid. The reaction with hydrogen peroxide that diphenyl oxalate undergoes to produce a photon of light is shown below:
The reaction rate is pH dependent, and slightly alkaline conditions achieved by adding a weak base, e.g. salicylic acid, will produce brighter light. The 2,4,6-trichlorophenole ester of oxalic acid is a solid and thus easier to handle. Furthermore, since trichlorophenolate is the better leaving group, the reaction will proceed faster, again producing brighter light, as compared to the phenole ester.
The following colors can be produced by using different dyes:
| Color | Compound |
|---|---|
| Blue | 9,10-Diphenylanthracene |
| Green | 9,10-Bis(phenylethynyl)anthracene |
| Yellow-green | Tetracene |
| Yellow | 1-Chloro-9,10-bis(phenylethynyl)anthracene |
| Orange | 5,12-Bis(phenylethynyl)-naphthacene, Rubrene, Rhodamine 6G |
| Red | Rhodamine B |
References
- ↑ Ma X. B., Wang S. P., Guo H. L., Xu G. H. (2003). "Preparation of diphenyl oxalate from transesterification of dimethyl oxalate with phenol over TS-1 catalyst". Chinese Chemical Letters. 14 (5): 461-464(4). Retrieved 2007-07-05.