Synthesis and evaluation of diaryl oxalate esters for low-intensity chemiluminescent illumination

Abstract

Various diaryl oxalate esters have been prepared from oxalyl chloride and substituted salicylates. A number of intermediates and byproducts were obtained from chlorinations of salicyclic acid and their mechanistic significance has been discussed. The chemiluminescent emission from the oxalates in the presence of hydrogen peroxide has been examined in the search for low-intensity illumination of at least 10 h duration. Bis(2-alkoxycarbonyl-4,6-dinitrophenyl) oxalates were too unstable while the chemiluminescence of the bis(6-alkoxycarbonyl-2,4,5-trichloropheny) oxalates could not be adjusted suitably. Some bis(6-alkoxycarbonyl-2,4-dichlorophenyl) oxalates were prepared and, by treatment with various combinations of potassium salicylate and oxalic acid, satisfactory low-intensity light emission could be achieved.