Mass-spectrometric studies of rate constants for addition reactions of hydrogen and of deuterium atoms with olefins in a discharge-flow system at 300.deg.K

1971 ◽  
Vol 75 (10) ◽  
pp. 1601-1610 ◽  
Author(s):  
H. Niki ◽  
E. E. Daby ◽  
B. Weinstock
1991 ◽  
Vol 94 (4) ◽  
pp. 2794-2806 ◽  
Author(s):  
Ronald J. Duchovic ◽  
Albert F. Wagner ◽  
Ralph Eric Turner ◽  
David M. Garner ◽  
Donald G. Fleming

1986 ◽  
Vol 64 (11) ◽  
pp. 2192-2195 ◽  
Author(s):  
William E. Jones ◽  
Joseph L. Ma

The absolute rate constants for the reaction of H atoms with methyl- and vinyl-halides have been determined using esr spectroscopy and a conventional gas flow system. The rate constants determined at 298 ± 2 K at a pressure of 0.55 Torr are methane, (1.7 ± 0.3) × 10−17; ethane, (2.3 ± 0.5) × 10−17; methylfluoride, (4 ± 3) × 10−15; methylchloride, (8 ± 2) × 10−16; methylbromide, (2.1 ± 0.6) × 10−14; vinylfluoride, (1.47 ± 0.02) × 10−13; vinylchloride, (1.66 ± 0.08) × 10−13; and vinylbromide (4.07 ± 0.73) × 10−13 in units of cm3 molecule−1 s−1.


The development of an ‘on-line’ computer for use with a combined gas chromatographymass spectroscopy (g.c.-m.s.) technique in the study of heterogeneous catalysis is described and discussed with reference to the reactions of ethylene and deuterium on oxides. Emphasis has been placed on the selectivities shown by a number of catalysts for the exchange and addition reactions. Magnesium oxide effects the exchange of ethylene without production of ethane even at 671 K; y-alumina also exhibits a high selectivity for exchange. In contrast, on chromium oxide (Cr20 3) at 197 K and zinc oxide at 273 K, ethylene undergoes rapid deuteration with no observable exchange of the olefin. For the range of catalysts studied the ratio of rate constants for the exchange and addition reactions decreases in the order: MgO > Al 2 O 3 > TiO 2 ~ Fe 2 O 3 > Co 3 O 4 > ZrO 2 > ZnO ~ Cr 2 O 3 . An explanation for the marked differences in catalytic behaviour within this group of oxides is provided.


1995 ◽  
Vol 99 (45) ◽  
pp. 16566-16570 ◽  
Author(s):  
Paul S. Monks ◽  
Louis J. Stief ◽  
Dwight C. Tardy ◽  
Joel F. Liebman ◽  
Zhengyu Zhang ◽  
...  

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