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1990 (1)
1977 (1)
1Author    Requires cookie*
 Title    Radiation Chemistry of Carbohydrates, X* y-Radiolysis of Crystalline D-Glucose and D-Fructose  
 Abstract    i z d a r o g l u , D. H e n n e b e r g , K . N e u w a l d , G. S c h o m b u r g and C. v o n S o n n t a g In stitu t für Strahlenchemie im M ax-Planck-Institut für Kohlenforschung, Mülheim a. d. Ruhr a-D-Glucose and ß-D-fructose were y-irratiated in the solid (polycrystalline) state at room temperature at doses o f 3.5 • 1020-4 .2 • 1021 eV g-1 (dose rate 1.16 • 1018 eV g_1 min_1). Carbohydrate products containing < 6 carbon atoms were identified and their G-values (in parentheses) measured. Glucose: Dihydroxyacetone (1) (0.05), 3-deoxy-tetrose (2) (O.OI5), l,4-dideoxy-2-pentu-lose (3) (0.05), 2,4-dideoxy-pentose (4) (O.O8 5), 2,4-dideoxy-pentonic acid (5), 2,3-dideoxy-pentos-4-ulose (6) (together 0.03a), threose (7), erythrulose (8), erythrose (9), erythronic acid (10) (together 0.04), l-deoxy-2-pentulose (11) (0.005), 2-deoxy-ribose (12) (0.25), 3-deoxy-pentosulose (13) (0.02), 3,5-dideoxy-hexonic acid (14) (0.02), 2,3-dideoxy-hexonic acid (15) (0.01), arabinose (16) (0.25), ribose (17), ribonic acid (18) (together 0.02), 2-deoxy-2-C-hydroxymethyl-pentonic acid (19) (0.06), 5-deoxy-gluconic acid (20), 2-deoxy-5-keto-glucose (21), 2-deoxy-gluconic acid (22), 2-deoxy-3-keto-glucose (23), 3-deoxy-glucosone (24), 3-deoxy-gluconic acid (25), 3-deoxy-4-keto-glucose (26), 3-deoxy-mannonic acid (27) (together 0.4). Identified but nor measured quantitatively were glucosone (28), 3-keto-glucose (29), 4-keto-glucose (30), 5-keto-glucose (31) and gluconic acid (32). G(H2) = 5.75; G (C02) = 0.7. Fructose: 7-9 (together 0.65), 3-deoxy-pentonic acids (37), 3-deoxy-pentosulose (38) (together 0.3), arabonic acid (39) (0.1), 18 (0.05), 6-deoxy-2,5-hexodiulose (40) (40). Identified but not measured quantitatively were glyceraldehyde (34), butanone-(3)-diol-(l,2) (35) and 2 -and 3-deoxy-hexodiuloses. G(H2) = 4.75, G (C02) = 0.05. Reaction schemes are proposed to account for the form ation of the products. The scission of the hemiacetal bond and of the C-H and C-C bonds next to it appears to be typical for solid state irradiations. The formation of deoxy-compounds is observed both in the solid state and in aqueous solution. The form ation o f dideoxy-compounds is only prominent in the solid state. In polycrystalline fructose a chain reaction is induced leading to 6-deoxy-2,5-hexodiulose (40). 
  Reference    (Z. Naturforsch. 32b, 213—224 [1977]; received October 27 1976) 
  Published    1977 
  Keywords    GC-MS, G-Values, Radical Reactions, Chain Reaction 
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 TEI-XML for    default:Reihe_B/32/ZNB-1977-32b-0213.pdf 
 Identifier    ZNB-1977-32b-0213 
 Volume    32 
2Author    Shailesh Phulkar, Balijepalli Sethu, M. Adhava Rao, Heinz-Peter Schuchmann, Clemens Von SonntagRequires cookie*
 Title    Radiolysis of Tertiary Butyl Hydroperoxide in Aqueous Solution. Reductive Cleavage by the Solvated Electron, the Hydrogen Atom, and, in Particular, the Superoxide Radical Anion  
 Abstract    The reactions o f the solvated electron, the H atom, the OH radical and the superoxide radi­ cal anion with /-butylhydroperoxide (/-BuOOH) have been studied in aqueous solutions using y-radiolysis and pulse radiolysis to generate these radicals. The solvated electron reacts rapidly with r-BuOOH (k = 5 x 109 dm 3 m ol" 1 s~') yielding /-BuO ' and OH in a ratio o f 4:1. The yield o f r-BuO' has been determined by measuring its fragmentation product, acetone. The H atom reacts more slowly with r-BuOOH (k = 5x 107 dm 3 m o l-1 s"1). There is very little H-abstraction from the methyl and the hydroperoxyl groups (about 3%), the main reac­ tion again being the scission o f the hydroperoxyl function with a branching ratio /-BuO'/'OH o f about unity. The OH radical reacts with /-BuOOH considerably more slowly (k = 8 x 107 dm3 m o l" 1 s ' 1) than with /-butanol (k = 5 X 108 dm3 m o l-1 s"1) with an approximate preference o f 8:1 o f ab­ stracting a methyl hydrogen over a hydroperoxyl hydrogen atom. The carbon-centered radical undergoes y-cleavage (k ~ 102 s"1) thereby reforming an OH radical. The resulting chain reac­ tion is rather short (maximum yield G (2-methyl-1,2-epoxypropane), 26 x 10"7 mol / ' at low dose rate) due to H-abstraction at the hydroperoxyl function o f r-BuOOH by the OH radical. The superoxide radical anion also reacts with /-BuOOH by cleaving the hydroperoxyl func­ tion. Its reactivity is, however, rather low (k = 5 dm3 m ol" 1 s"1). 
  Reference    Z. Naturforsch. 45b, 1425—1432 (1990); received May 9 1990 
  Published    1990 
  Keywords    /-Butyl Hydroperoxide, Solvated Electron, H Atom, Superoxide Radical, Hydroxyl Radical, Pulse R adiolysis, Chain Reaction 
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 TEI-XML for    default:Reihe_B/45/ZNB-1990-45b-1425.pdf 
 Identifier    ZNB-1990-45b-1425 
 Volume    45