Gas-phase reactions between hydrocarbons and metal oxides: the aluminum monoxide + methane reaction from 590 to 1380 K
作者:David P. Belyung、Arthur Fontijn、Paul Marshall
DOI:10.1021/j100116a002
日期:1993.4
A recent ab inito study suggested that gaseous metal oxides can directly abstract H atoms from hydrocarbons, but with considerable barriers. To try to confirm the occurrence of such reactions, the title reaction has been studied in a high-temperature fast-flow reactor. The data are well described by the fitting expression k(590-1380 K) = 9.6 X 10(-39)(T/K)7.96 exp(2468 K/T) cm3 Molecule-1 s-1, with 2sigma precision limits varying with temperature from +/- 4% to +/- 12%. The corresponding 2sigma accuracy limits are about +/- 25%. Comparison of this result to further ab initio and conventional transition-state theory calculations suggests that direct abstraction indeed can occur at the higher temperatures but that one or more other channels, possibly involving AlO insertion into a C-H bond, dominate in the initial attack step. The potential implications of this work for catalytic conversion of methane to higher hydrocarbons are considered.
Infrared matrix-isolation studies of the interactions and reactions of Group 3A metal atoms with water
作者:R. H. Hauge、J. W. Kauffman、J. L. Margrave
DOI:10.1021/ja00539a005
日期:1980.9
Kinetics of the reaction aluminum(2P0) + water over an extended temperature range
作者:Roy E. McClean、H. H. Nelson、Mark L. Campbell
DOI:10.1021/j100140a024
日期:1993.9
The temperature dependence of the reaction Al(P-2(0)) + H2O has been investigated over the temperature range 298-1174 K. Aluminum atoms were produced by photodissociation of Al(C2H5)3 and were detected by laser-induced fluorescence. Nonlinear Arrhenius behavior is observed, and the measured rate constants can be described by the expression k(T) = (1.9 +/- 1.5) X 10(-12) exp[-(0.88 +/- 0.44 kcal mol-1)/RT] + (1.6 +/- 0.7) X 10(-10) exp[-(5.7 +/- 0.9 kcal mol-1)/RT] cm3 s-1, where the uncertainties represent +/-2sigma. At room temperature the rate constant is pressure independent between 10 and 110 Torr total pressure (Ar buffer gas). Results are interpreted in terms of two metathesis reactions with different Arrhenius parameters, one yielding AlO and the other AlOH.
Matrix-isolation studies by electronic spectroscopy of group IIIA metal–water photochemistry
作者:Monte A. Douglas、Robert H. Hauge、John L. Margrave
DOI:10.1039/f19837901533
日期:——
This paper reports an investigation of the electronic structures of the GroupIIIA metal atom hydration reaction intermediates (M⋯OH2adducts) and their subsequent photolysis products (HMOH, MOH and MO) where M = Al, Ga and In. The metal–water interaction in the adduct is sufficiently strong to perturb the electronic structure of the metal atom; consequently, one observes a unique band structure for