Continuous process of the vacuum ultraviolet- (VUV-) photochemical oxidation of thiophene in the gas phase

Abstract

Thiophene was taken as a model compound for investigations on the efficiency of a continuous process of the vacuum-ultraviolet- (VUV-) photochemically initiated oxidation and mineralization of sulfur containing organic compounds in the gas phase. In the presence of molecular oxygen, atomic oxygen and ozone were photochemically generated and are assumed to initiate or participate in the (thermal) oxidation network. Addition of water vapor for an additional initiation of the oxidation by hydroxyl radicals did not accelerate the process. For comparison, thiophene was exposed to ozone and oxidized under otherwise the same experimental conditions, but complete mineralization was only found in the photochemical process and for relatively small concentrations of the substrate. The result may be explained by low rates of secondary thermal reactions of a number of identified intermediate products. Combining already published results and mechanistic hypotheses with the results of the present work, pathways of oxidative degradation are proposed. The photolysis of thiophene in molecular nitrogen confirmed earlier findings.

Degradable Semiconducting Oligomer Amphiphile for Ratiometric Photoacoustic Imaging of Hypochlorite

“…After the reaction, mass spectroscopy was able to detect 2-(10-(6-azidohexyl)-5,5-dioxido-10 H -phenothiazin-3-yl)-2-oxoacetic acid ( 11 ) and 2,2′-(2,5-bis­(2-ethylhexyl)-3,6-dioxo-2,3,5,6-tetrahydropyrrolo­[3,4- c ]­pyrrole-1,4-diyl)­bis­(2-oxoacetic acid) ( 12 ) as the final reaction products. According to the reported literatures, ,, the sulfur atoms in thiophene and phenothiazine are sensitive to oxidation, particularly to ClO – . First, the sulfur atoms are oxidized by ClO – to form the corresponding sulfones.…”