6683-73-4Relevant academic research and scientific papers
Relative Reactivities of Some C-H Bonds in Hydrogen Abstraction by Methyl Radicals at 950 K
Kopinke, F.-D.,Remmler, M.,Mensing, H.,Hugo, P.
, p. 1171 - 1175 (1994)
Relative reactivities of C-H bonds in alkylbenzenes in the hydrogen abstraction by methyl radicals at about 950 K were determined by means of labeled compounds.The following values normalized to the primary aliphatic C-H bond were obtained: rPh H = 0.7 +/- 0.1; rBz-H = 4.5 +/- 0.5; rsec,benzyl = 8.7 +/- 1.0; rtert, benzyl = 9.0 +/- 1.0.The combination of these high-temperature values with low-temperature kinetic data from the literature reveals the absence of a straight connection between strength and reactivity of C-H bonds.
Heterogeneous palladium-catalyzed exchange labelling of representative organic compounds with tritium gas
Williams,Than,Rabbani,Long,Garnett
, p. 1 - 14 (2007/10/02)
A range of organic substrates was successfully exchanged with tritium gas using NaBH4-reduced palladium oxide or chloride as catalyst. Exchange conditions involved a reaction temperature of 100°C, a reaction time of 3 days, and products were analyzed by radio-gas chromatography and 3H NMR spectroscopy. Both aromatic and aliphatic compounds underwent exchange, 18 of the 22 substrates incorporated >35% of the available tritium, and most products showed high radiochemical purity. 3H NMR analyses showed that both alkanes and the alkyl chains of alkylbenzenes were rapidly and evenly labelled. Some aromatic compounds showed general ring exchange while others showed high specificity. These results for hulk palladium catalyst are strikingly different from those obtained with bulk platinum and supported palladium catalysts. The results are discussed in terms of currently accepted mechanisms of heterogeneous metal catalyzed hydrogen isotope exchange reactions.
Tritium Gas Exchange with Aromatic and Aliphatic Hydrocarbons Over Metal Containing ZSM-5 and Related Zeolites
Long, Mervyn A.,Garnett, John L.,Williams, Philip G.
, p. 1057 - 1059 (2007/10/02)
Platinum and palladium containing Y-zeolite, mordenite and ZSM-5 catalyse efficient exchange at 100 deg C between elemental tritium and aromatic or aliphatic hydrocarbons, the tritium orientation in the organic molecule showing characteristics of both metal and zeolite catalysis.The hydrogen forms of the same zeolites (i.e. without metal) also activate elemental tritium for aromatic exchange at 120-150 deg C, which shows that a metal component is not necessary for activation of elemental hydrogen even at modest temperatures.
