The photochemistry of SO2/Cl2/O2 gas mixtures: Synthesis of the novel peroxide ClSO2OOSO2Cl

ROMANO, ROSANA M.; DELLA VEDOVA, CARLOS O.; BECKERS, HELMUT; WILLNER, HELGE

INORGANIC CHEMISTRY

AMER CHEMICAL SOC

Año: 2009 vol. 48 p. 1906 - 1910

0020-1669

ABSTRACT Photochemical induced gas-phase reactions of Cl2/SO2/O2 mixtures at -78 0C have been investigated in a preparative scale. The sulfuryl chlorides ClSO2(OSO2)nCl n=0,1,2 along with SO3, and the hitherto unknown bis(chlorosulfuryl)peroxide, ClSO2OOSO2Cl, have been obtained. The new peroxide has been purified by trap to trap distillation and conclusively characterized by gas phase and matrix IR, as well as Raman spectroscopy. At room temperature the peroxide decomposes to form quantitatively Cl2 and SO3. DFT calculations suggest that ClSO2OOSO2Cl consists at ambient temperatures in at least two different rotamers, while in Ar-matrix isolation experiments at 15 K only the most stable form has been found. The mechanism of the formation of the peroxide via the ClSO2OO peroxy radical, and the supposed involvement of ClSO3· intermediate have been discussed.