Ozonation of diclofenac in aqueous solution in the presence and absence of an *OH scavenger, tertiary butanol (t-BuOH), was studied, and the most important reaction intermediates and products were identified. The second-order O3 rate constantwas determined by competition with buten-3-ol and was found to be 6.8 x 10(5) M(-1) s(-1) at 20 degrees C. From this high rate constant, it has been concluded that O3 must initially add on the amino nitrogen. Decomposition of the adduct results in the formation of O3*- (--> *OH) and aminyl radical precursors. A free *OH yield of 30% was estimated based on the HCHO yields generated upon reaction of *OH with 0.01 M t-BuOH. Almost all diclofenac reacted when the molar ratio of O3/diclofenac was approximately 5:1 in the presence of t-BuOH and approximately 8:1 in its absence. As primary reaction products (maximum yield), diclofenac-2,5-iminoquinone (32%), 5-hydroxydiclofenac (7%), and 2,6-dichloroaniline (19%) were detected with respect to reacted diclofenac in the presence of t-BuOH. These primary products degraded into secondary ones when the O3 dose was increased. In the *OH-mediated reaction (absence of t-BuOH) small yields of 5-hydroxydiclofenac (4.5%), diclofenac-2,5-iminoquinone (2.7%), and 2,6-dichloroaniline (6%) resulted. Practically all Cl- (95%) was released in the absence of t-BuOH but only about 45% in the presence of t-BuOH at an O3/diclofenac molar ratio of 10: 1. Based on the reaction products, mechanisms that may account for the high O3 consumption during ozonation of diclofenac are suggested. For technical applications, adequate supply of O3 is needed not only to eliminate diclofenac, but also for the degradation of its potentially toxic products like diclofenac-2,5-iminoquinone and 5-hydroxydiclofenac.
Durch Oxydation von Octafluornaphthalin (2) mit konzentrierter Salpetersaure wurde Tetrafluorphthalsaure (1) als maRig starke Saure im praparativen MaRstab erhalten. WLhrend sich die Alkali-und Erdalkalisalze von 1 thermisch rasch und ohne definierte Reaktionsprodukte zersetzten, erfolgt die thermische Zersctzung von Quecksilbertetrafluorphthalat (3) in zwei getrennten, isoliert durchfuhrbaren Schritten. Bei 2 2 0 erfolgt unter Abspaltung von 1 Mol COz pro Mol 3 die Bildung des offenbar trimeren Produktes 4. Bei 300'' bildet sich unter Abspaltung von 2 Mol C02 pro Mol 3 ein Pyrolyseprodukt der Konstitution 5. 5 wird rnit Ag zu Perfluorbiphenylen (6), rnit J 2 zu 1.2 Dijod-tetrafluorbenzol (7) umgesetzt, wahrend 4 rnit Salzsaiure zur Tetrafluorbenzoesaure 8 gespalten wird. 12) A. D. Campbell und A . M. Macdonald, Analytica chim. Acta [Amsterdam] 26, 275 (1962). 13) W. Schoninger, Mikrochim. Acta 1955, 123.
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