Browsing by Author "Kläning, Ulrik K."

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    Photoinduced oxidation of propan-2-ol by acid chromate
    (Journal of the Chemical Society : Faraday Transaction - I. The Chemical Society, London. 1977, 73 (03), 1977) Kläning, Ulrik K.
    The photoinduced oxidation of propan-2-ol by acid chromate has been studied (i) by flash photolysis, (ii) by quantum yield measurements at low light intensity, (iii) by e.s.r. measurements during photolysis of solutions containing a spin trap, and (iv) by e.s.r. measurements of glassy samples photolysed at –165°C. It was found that CrIV is formed in the primary processes, the most efficient of which involves the ester of acid chromate. The rate of formation of the ester was measured. A mechanism for the subsequent reactions of CrIV is given. In general the reactions of CrIV with another CrIV or with CrV are fast compared with the reaction of CrIV with propan-2-ol in the formation of 2-hydroxypropyl radicals. The reaction of CrIV with CrVI is immeasurably slow.
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    Photolysis of Periodate and Periodic Acid in Aqueous Solution
    (Journal of the Chemical Society : Faraday Transaction - I. The Chemical Society, London. 1978, 74 (09-12), 1978) Kläning, Ulrik K.; Sehested, Knud
    The photochemistry of periodate and periodic acid in aqueous solution was studied (i) by quantum yield measurements at low light intensity (ii) by flash photolysis, and (iii) by photolysis of glassy samples at 77 K. The photochemical studies were supplemented with pulse radiolysis studies of aqueous periodate solutions and with kinetic studies using stopped-flow technique. In strongly alkaline solution the photodecomposition of periodate proceeds via formation of O– and IVI. At pH < 12 an additional primary process is the formation of IV and H2O2. In neutral solution O3P is formed in a small yield. The energetics of the reaction of O1D with H2O with formation of H2O2 is discussed. It is suggested that oxygen atoms are formed only from IO4– and not from other IVII species. Mechanisms for the secondary processes involving IVIII and IVI are given. IVIII and its relatively stable complex with IVII both form IV IVII and O2. Depending on pH and concentration, IVI either disproportionates to IV and IVII, reacts with IVII with formation of IV and IVIII or dissociates into O–(OH) and IV.