Journal Articles (before-1995)

Permanent URI for this collectionhttp://localhost:4000/handle/123456789/16938

Browse

Subject: search.filters.subject.Pulse radiolysis

Search Results

Now showing 1 - 3 of 3
  • No Thumbnail Available
    Item
    Pulse Radiolysis of 3,4-Dihydroxytoluene
    (Journal of the Chemical Society : Faraday Transaction - I. The Chemical Society, London. 1977, 73 (09), 1977) Gohn, Michael; Getoff, Nikola
    Pulse radiolysis experiments of 3,4-dihydroxytoluene (DHT) were performed in aqueous solutions over a wide pH range (2–12). The rate constants for the reaction of DHT with the primary products of water radiolysis were determined: k(e–aq+ DHT)=(2 ± 0.2)× 107 dm3 mol–1 s–1 at pH = 7 and (1 ± 0.1)× 107 dm3 mol–1 s–1 at pH = 12; k(H + DHT)=(1.5 ± 0.2)× 109 dm3 mol–1 s–1 at pH = 2; k(OH + DHT)=(1.6 ± 0.1)× 1010 dm3 mol–1 s–1(pH = 2–7). The absorption spectrum of the H-adduct possesses two maxima (ε280= 290 m2 mol–1 and ε350= 300 m2 mol–1) and disappears according to a second order reaction (k2= 1.8 × 108 dm3 mol–1 s–1). By reaction of OH with DHT, an OH-adduct is formed, which is subsequently converted into the corresponding semiquinone radical by splitting water (k1= 3.7 × 104 s–1 at pH = 6.5). The species produced by reaction of DHT with electrons has also two absorption maxima (ε280= 300 m2 mol–1 and ε350= 120 m2 mol–1). A second order decay (k2= 9 × 108 dm3 mol–1 s–1) was established. Probable reaction mechanisms are suggested.
  • No Thumbnail Available
    Item
    Bipyridylium Quaternary Salts and Related Compounds: Part 6.—Pulse Radiolysis Studies of the Reaction of Paraquat Radical Analogues with Oxygen
    (Journal of the Chemical Society : Faraday Transaction - I. The Chemical Society, London. 1978, 74 (3), 1978) Farrington, John A.; Ebert, Michael; Land, Edward J.
  • No Thumbnail Available
    Item
    Photochemistry and radiation chemistry of 9,10-anthraquinone-2-sodium sulphonate in aqueous solution. Part 3.—Pulse and gamma radiolysis
    (Journal of the Chemical Society : Faraday Transaction - I. The Chemical Society, London. 1977, 73 (05), 1977) Clark, K. P.; Stonehill, H. I.
    Electron-pulse and gamma radiolysis of “aqueous” solutions of the title compound (D) in the range pH 14 to > 100 % H2SO4 give the same products as photolysis (mainly α- and β-monohydroxyderivatives ROH with some polyhydroxylated D, and in the absence of oxygen, semiquinone and quinol), and the same variation with pH or acidity of the α : β ROH isomer ratio. Of the following rate constants (all in dm3 mol–1 s–1) the first three were determined by pulse radiolysis, the others by scavenger competition during gamma radiolysis : 2 DOH˙→ DHOH + ROH, 2 k=(1.41 ± 0.17)× 109; DOH˙+ O2→ DOH˙ O2., k=(1.39 ± 0.17)× 107; 2 D–˙→ D + D2–, 2 k=(1.33 ± 0.18)× 109; D + OH·→ DOH·, k=(2.68 ± 0.25)× 109; D + O·–→ DO·–, k= 6.1 × 107; D + O.–→ products other than DO.–, k= 1.63 × 108[this reaction is postulated to explain the fall in G(ROH) at pH > 12]. The effect of individual scavengers and of high alkalinity on the yield of ROH is different in photolysis and radiolysis. This suggests that since OH· is known to be the precursor of DOH· in radiolysis, any photolysis mechanism involving intermediate free OH· production is invalid.