Mechanism of Chemiluminescence Reaction between Hypobromite and Ammonia or Urea

Abstract

The reaction kinetics, the chemiluminescence spectra, the products, and the lifetimes of emission species for the chemiluminescence reaction between hypobromite and ammonia or urea in an alkaline aqueous solution were investigated. Results show that the reaction mechanism for ammonia chemiluminescence is different from that for urea. The reaction of ammonia and hypobromite produces NO2 in the gaseous phase and NO2− in solution; however, the reaction of urea and hypobromite does not. For the reaction of ammonia and hypobromite, chemiluminescence intensity obeys 1.5 order kinetics for hypobromite concentration when ammonia is in excess, but the reaction of urea and hypobromite obeys second order kinetics for hypobromite when urea is in excess. The spectrum of the chemiluminescence from the ammonia and urea with hypobromite shows a maximum intensity at 710, and at 510 nm, respectively. The chemiluminescence lifetimes of the emission species were 0.056 and 0.092 s for the reaction of ammonia and the reaction of urea, respectively. The chemiluminescence species of the reaction between hypobromite and ammonia seems to be excited NO2, that for urea seems to be excited N2.

Near-infrared chemiluminescence from the oxidation of ammonia in aqueous alkaline solution

“…2b) but is more broadly distributed. Furthermore, the chemiluminescence spectrum is markedly different to that reported for the 2 B 2 excited state of nitrogen dioxide, which appears to negate the previous postulate (11) that the oxidation of ammonia with hypobromite offers an alternative route to the excited intermediate that is produced in the gas-phase reaction between nitrogen monoxide and ozone. The discrepancy in the region between 700 nm and 900 nm on the spectra shown in Figs 1 and 2a is caused by the reduced sensitivity of the InGaAs detector in the visible region compared to the near-infrared (16).…”

“…The main products of the reaction between ammonia and hypobromite are molecular nitrogen and bromide, but small quantities of nitrogen oxides have also been detected (11). The spectral distribution of this reaction in the near-infrared appears different to that observed for the gas-phase reaction between nitrogen monoxide and ozone, but it does not provide sufficient evidence to identify the emitting species.…”

“…Hu and co-workers (11) found that the chemiluminescence arising from the oxidation of ammonia with alkaline hypobromite increased in intensity from 600 nm to 800 nm after correction of the instrumental response, but the poor sensitivity of the detector in the near-infrared region prevented further investigation. Based on this limited evidence, they suggested that the oxidation of normally located.…”

“…ammonia with hypobromite might provide an alternative route to the excited state of nitrogen dioxide that is formed in the gas-phase reaction between nitrogen monoxide and ozone (11). The luminescence from this excited species is characterized by a broad emission from 540 nm to 3000 nm, with a maximum intensity at around 1200 nm (1).…”

Study on the Indirect Electrochemical Detection of Ammonium Ion with In Situ Electrogenerated Hypobromous Acid

“…The hypohalites were reported to be as the chemiluminescence reagents for the determination of ammonium ion in rainwater samples [14,15]. In this study, it was found that the voltammetric behavior in the oxidation of bromide was greatly affected by the co-existed ammonium ion.…”