Some hydrogen atom abstraction reactions of CF2H and CFH2 radicals, and the C?H bond dissociation energy in CF2H2

1969 ◽  
Vol 1 (6) ◽  
pp. 509-525 ◽  
Author(s):  
G. O. Pritchard ◽  
M. J. Perona
Keyword(s):  
Hydrogen Atom ◽  
Bond Dissociation Energy ◽  
Dissociation Energy ◽  
Hydrogen Atom Abstraction ◽  
Bond Dissociation

The C—Br bond dissociation energy in halogenated bromomethanes

1951 ◽  
Vol 209 (1096) ◽  
pp. 110-131 ◽  
Keyword(s):  
Bond Dissociation Energy ◽  
Dissociation Energy ◽  
Methyl Bromide ◽  
Frequency Factor ◽  
Unimolecular Dissociation ◽  
Bond Dissociation Energies ◽  
Kcal Mole ◽  
Fast Reaction ◽  
Bond Dissociation ◽  
Dissociation Energies

The pyrolyses of methyl bromide and of the halogenated bromomethanes, CH 2 CI. Br, CH 2 Br 2 , CHCl 2 .Br, CHBr 3 , CF 3 Br, CCI 3 . Br and CBr 4 , have been investigated by the ‘toluene-carrier' technique. It has been shown that all these decompositions were initiated by the unimolecular process R Br → R + Br. (1) Since all these decompositions were carried out in the presence of an excess of toluene, the bromine atoms produced in process (1) were readily removed by the fast reaction C 6 H 5 .CH 3 + Br → C 6 H 5 . CH 2 • + HBr. Hence, the rate of the unimolecular process (1) has been measured by the rate of formation of HBr. The C—Br bond dissociation energies were assumed to be equal to the activation energies of the relevant unimolecular dissociation processes. These were calculated by using the expression k ═ 2 x 10 13 exp (- D/RT ). The reason for choosing this particular value of 2 x 10 13 sec. -1 for the frequency factor of these reactions is discussed. The values obtained for the C—Br bond dissociation energies in the investigated bromomethanes are: D (C—Br) D (C—Br) compound (kcal./mole) compound (kcal./mole) CH 3 Br (67.5) CHBr 3 55.5 CH 2 CIBr 61.0 CF 3 Br 64.5 CH 2 Br 2 62.5 CCI 3 Br 49.0 CHCl 2 Br 53.5 CBr 4 49.0 The possible factors responsible for the variation of the C—Br bond dissociation energy in these compounds have been pointed out.

The mean bond dissociation energy of the carbonmagnesium bond in bis(2,2-dimethylpropyl)magnesium

2010 ◽  
Vol 102 (2) ◽  
pp. 109-113 ◽  
Author(s):  
O. S. Akkerman ◽  
G. Schat ◽  
E. A. I. M. Evers ◽  
F. Bickelhaupt
Keyword(s):  
Bond Dissociation Energy ◽  
Dissociation Energy ◽  
Bond Dissociation ◽  
The Mean
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