Enthalpy of Formation of Anisole: Implications for the Controversy on the O–H Bond Dissociation Enthalpy in Phenol

2014 ◽  
Vol 118 (46) ◽  
pp. 11026-11032 ◽  
Author(s):  
Ricardo G. Simões ◽  
Filipe Agapito ◽  
Hermínio P. Diogo ◽  
Manuel E. Minas da Piedade
1984 ◽  
Vol 16 (8) ◽  
pp. 703-709 ◽  
Author(s):  
Steven W. Govorchin ◽  
Adli S. Kana'an ◽  
Joseph M. Kanamueller

1984 ◽  
Vol 62 (9) ◽  
pp. 1850-1859 ◽  
Author(s):  
A. Martin de P. Nicholas ◽  
Donald R. Arnold

The relationship between radical stability and bond dissociation enthalpy (BDH) is reexamined. It is shown that relative stabilization energies of radicals are not equal to relative BDH values. Net stabilization energies of radicals, SE0[R•, RX] are defined relative to the R components of closed shell species RX (R(RX)). These components are chosen such that they contain the same (or, approximately the same) net charge as that of the radical (R•). The following results, relative to R = C2H5, were obtained: R•, SE0[R•, RX](kJ mol−1) for X = R (i.e., the dimer RR), CH3, and H; CH3•, 23, 32, 37; n-C3H7•, −2, −2, −3; i-C3H7•, −9, −14, −19; t-C4H9•, −25, −32, −38. These results show that the methyl radical is more destabilized and the n-propyl-, i-propyl-, and tert-butyl radicals are more stabilized than is predicted from the corresponding relative BDH (R—X) values. The intrinsic C—H bond strengths of chosen alkanes are considered. Relative to the C—H bond in ethane, the bond in methane is found to be weaker by 8.12 kJ mol−1 and the primary and secondary bonds in propane and the tertiary bond in methyl propane are stronger by 2.56, 7.98, and 17.12 kJ mol−1 respectively.


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