Generation of Singlet Oxygen by Decomposition of Triphenyl Phosphite Ozonide

This letter reports a study on producing gas-phase O2（a1Δ）by decomposition of triphenyl phosphite ozonide（（C6H5O）3 PO3，TPPO3）under a number of reaction conditions. For the first time，the cooperative emission at wavelengths 634 and 703 nm of O2（a1Δ）generated by TPPO3 decomposition are observed. Specifically，under the condition of catalyzed decomposition by pyridine of TPPO3 solution in CFCl3 at low temperature，the emission spectrum is the same as that from the basic hydrogen peroxide plus chlorine reaction. This shows the feasibility of developing a new source for singlet delta oxygen. However，in the experiments of spontaneous decomposition of solid TPPO3 and thermal decomposition of TPPO3 solution on a high temperature surface，the spectra have a wide emission background around the 634 and 703 nm peaks，which indicates the production of some excited species than O2（a1Δ）. Besides，there are about 2%-3% CO and 1. 5%-2% CO2 in the gaseous products together with a small amount of insoluble in acetone solid product，which imply that other than the formation of O2（a1Δ）and TPPO by unimolecular decomposition of TPPO3，more complicated reactions may take place. The study of the reaction mechanism，the optimization of the expertise of O2（a1Δ）generation by TPPO3 decomposition as well as measurement of absolute concentration of O2（a1Δ）are under way.