Pyrolysis mechanism of carbon matrix precursor cyclohexane - The formation of condensed-ring aromatics and the growing process of molecules
Based on the experiments, the UAM I method was adopted to investigate benzene condensation of an important intermediate and the molecule growing mechanism during the cyclohexane pyrolysis process. The conclusions were drawn as follows: (1) from the viewpoint of thermodynamics, the condensation of benzene and C4H5 center dot is a spontaneous reaction and the rising temperature will increase the spontaneous tendency of the reaction. (2) From the viewpoint of kinetic, the condensation of benzene and C4H5 center dot is a two-step reaction. The rate-determining step is step 2 of hydrogen removal from intermediate C10H10 (11) with the activation energy of 350.61 kJ/mol below 1473 K while the rate-determining step is step I that free radical C4H5 center dot attacks benzene to form intermediate C10H10 (11) with the activation energy Delta E-0 not equal(theta) 31 74 kJ/mol above 1473 K. (3) The space 0 structure, electronic structure and thermodynamics parameters of molecular reaction of dense-ring aromatizing compounds can be used to replace the resonance energy and free valence tojudge the activation of thermodynamic reaction of compounds. And (4) the analysis of the space structure, electronic structure and thermodynamic parameters show that the growing process of molecules with benzene used as initial reactants becomes more easier as the multi-ring aromatizing molecular system increases. (c) 2006 Elsevier Inc. All rights reserved.
pyrolysis mechanism cyclohexane condensed-ring aromatics aromatization carbon/carbon composites uam1 method computation