Diphenyl oxalate

Diphenyl oxalate

Names
IUPAC name diphenyl oxalate
Other names diphenylethandioate, oxalic acid diphenyl ester, cyalume, DPO
Identifiers
CAS Number	3155-16-6
ChemSpider	17449
Jmol interactive 3D	Image
PubChem	18475
InChI InChI=1S/C14H10O4/c15-13(17-11-7-3-1-4-8-11)14(16)18-12-9-5-2-6-10-12/h1-10H Key: ULOZDEVJRTYKFE-UHFFFAOYSA-N InChI=1/C14H10O4/c15-13(17-11-7-3-1-4-8-11)14(16)18-12-9-5-2-6-10-12/h1-10H Key: ULOZDEVJRTYKFE-UHFFFAOYAB
SMILES O=C(Oc1ccccc1)C(=O)Oc2ccccc2
Properties
Chemical formula	C14H10O4
Molar mass	242.227 g/mol
Appearance	solid
Melting point	136 °C (277 °F; 409 K)
Thermochemistry
Std enthalpy of formation (ΔfH^o298)	129·0 ± 0·8[1]
Related compounds
Related compounds	Dimethyl oxalate
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Infobox references

Diphenyl oxalate (trademark name Cyalume) is a solid ester whose oxidation products are responsible for the chemiluminescence in a glowstick. It can be synthesized by fully esterifying phenol with oxalic acid. The reaction with hydrogen peroxide that diphenyl oxalate undergoes produces phenol and 1,2-dioxetanedione,^[2] which excites the dye and releases a photon as it decomposes to carbon dioxide.

The reaction rate is pH dependent, and slightly alkaline conditions achieved by adding a weak base, e.g., sodium salicylate, will produce brighter light. The 2,4,6-trichlorophenol 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 phenol 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

1. Carson, A. S.; Fine, D. H.; Gray, P.; Laye, P. G. (1971). "Standard enthalpies of formation of diphenyl oxalate and benzoic anhydride and some related bond dissociation energies". Journal of the Chemical Society B: Physical Organic: 1611. doi:10.1039/J29710001611.
2. Orosz, György (January 1989). "The role of diaryl oxalates in peroxioxalate chemiluminescence". Tetrahedron 45 (11): 3493–3506. doi:10.1016/S0040-4020(01)81028-0.