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'Radical Reactions' in keywords Facet   Publication Year 1977  [X]
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1977[X]
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    Requires cookie*
 Title    Radiation Chemistry of Carbohydrates, XV OH Radical Induced Scission of the Glycosidic Bond in Disaccharides  
 Abstract    H e n r y k Z e g o t a * * a n d C l e m e n s v o n S o n n t a g In the y-radiolysis of deoxygenated, NaO-saturated aqueous solutions of maltose, lactose, gentiobiose, melibiose, trehalose and sucrose carbohydrate products containing five or six carbon atoms have been identified and their G-values measured. These products originate from the OH radical induced scission of the glycosidic bond of the disaccharides. The nature of the products is in agreement with a reaction scheme proposed previously for the radical induced scission of the glycosidic bond of cellobiose. It involves hydrolysis and the rearrangements of radicals with the free spin next to the glycosidic bond and to the lactol bridge. The nature the glycosidic bond (a, ß, 1-4, 1-6, 1-1, 1, 2) has only little influence on the G-values of its scission which range between about 1.9 and 3.5. 
  Reference    (Z. Naturforsch. 32b, 1060—1067 [1977]; received May 31 1977) 
  Published    1977 
  Keywords    y-Radiolysis, G-values, Mass Spectra, Radical Reactions 
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 TEI-XML for    default:Reihe_B/32/ZNB-1977-32b-1060.pdf 
 Identifier    ZNB-1977-32b-1060 
 Volume    32 
3Author    Requires cookie*
 Title    Photolysis (A = 185 nm) of Liquid Acetaldehyde Dimethyl Acetal  
 Abstract    H e in z -P e t e r S c h u c h m a n n a n d C l e m e n s v o n S o n n t a g In stitut fü r Strahlenchemie im M ax-Planck-Institut für Kohlenforschung, Mülheim a. d. R uhr Deaerated liquid acetaldehyde dimethyl acetal has been photolyzed at X = 185 nm, and 28 products have been determined. The m ajor ones with their quantum yields are: methanol (0.59), methane (0.26), ethyl methyl ether (0.17), m ethyl vin yl ether (0.16), m ethyl form ate (0.14), ketene dimethyl acetal (0.1), ethane (0.06), hydrogen (0.06), and acetaldehyde (0.06). The m ajor prim ary processes are suggested to be the scission o f the C-OCH3 bonds (homolytic and molecular) and o f the O-CH3 bonds (homolytic). Minor processes are hydrogen elimination reactions and the scission o f the C-CH3 bond. 
  Reference    (Z. Naturforsch. 32b, 205 [1977]; received October 8 1976) 
  Published    1977 
  Keywords    UV, GC-MS, Quantum yields, Radical Reactions, Fragm entation Processes 
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 TEI-XML for    default:Reihe_B/32/ZNB-1977-32b-0205.pdf 
 Identifier    ZNB-1977-32b-0205 
 Volume    32