MECHANISM OF CHEMILUMINESCENCE REACTION BETWEEN HYPOBROMITE AND AMMONIA OR UREA

The reaction kinetics, the chemiluminescence spectra, the products, an d the lifetimes of emission species for the chemiluminescence reaction between hypobromite and ammonia or urea in an alkaline aqueous soluti on were investigated. Results show that the reaction mechanism for amm onia chemiluminescence is different from that for urea. The reaction o f ammonia and hypobromite produces NO2 in the gaseous phase and NO2- i n solution; however, the reaction of urea and hypobromite does not. Fo r the reaction of ammonia and hypobromite, chemiluminescence intensity obeys 1.5 order kinetics for hypobromite concentration when ammonia i s in excess, but the reaction of urea and hypobromite obeys second ord er kinetics for hypobromite when urea is in excess. The spectrum of th e chemiluminescence from the ammonia and urea with hypobromite shows a maximum intensity at 710, and at 510 nm, respectively. The chemilumin escence lifetimes of the emission species were 0.056 and 0.092 s for t he reaction of ammonia and the reaction of urea, respectively. The che miluminescence species of the reaction between hypobromite and ammonia seems to be excited NO2, that for urea seems to be excited N-2.