On the introduction of thermodynamic variables into reaction kinetics

Evans, M. G.; Polanyi, Michael

doi:10.1039/tf9373300448

Cited by 123 publications

(78 citation statements)

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“…[59] Basis set superposition errors (BSSE) were estimated by use of the counterpoise method. [60,61] Reaction rate coefficients, frequency factors, and activation energies were predicted on the basis of transition state theory (TST), [62][63][64] by using the in-house-developed software code TAMkin. [65] Tunneling corrections were not included, since it was previously shown that Eckart tunneling refinements lead to a decrease of approximately 5 kJ mol À1 in activation energies of hydrogen abstraction reactions from hydrocarbons.…”

Section: Methodsmentioning

confidence: 99%

Competitive Reactions of Organophosphorus Radicals on Coke Surfaces

Çatak

Hemelsoet

Hermosilla

et al. 2011

Chemistry A European J

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The efficacy of organophosphorus radicals as anticoking agents was subjected to a computational study in which a representative set of radicals derived from industrially relevant organophosphorus additives was used to explore competitive reaction pathways on the graphene-like coke surface formed during thermal cracking. The aim was to investigate the nature of the competing reactions of different organophosphorus radicals on coke surfaces, and elucidate their mode of attack and inhibiting effect on the forming coke layer by use of contemporary computational methods. Density functional calculations on benzene and a larger polyaromatic hydrocarbon, namely, ovalene, showed that organophosphorus radicals have a high propensity to add to the periphery of the coke surface, inhibiting methyl radical induced hydrogen abstraction, which is known to be a key step in coke growth. Low addition barriers reported for a phosphatidyl radical suggest competitive aptitude against coke formation. Moreover, organophosphorus additives bearing aromatic substituents, which were shown to interact with the coke surface through dispersive π-π stacking interactions, are suggested to play a nontrivial role in hindering further stacking among coke surfaces. This may be the underlying rationale behind experimental observation of softer coke in the presence of organophosphorus radicals. The ultimate goal is to provide information that will be useful in building single-event microkinetic models. This study presents pertinent information on potential reactions that could be taken up in these models.

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Section: Methodsmentioning

confidence: 99%

Competitive Reactions of Organophosphorus Radicals on Coke Surfaces

Çatak

Hemelsoet

Hermosilla

et al. 2011

Chemistry A European J

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“…However, for some reactions a marked increase in rate is observed. A completely satisfactory solution to the problem did not come until after transition-state theory (36)(37)(38) had been formulated in 1935. In terms of that theory, the rate should be expressed not as eq.…”

Section: Acid-base Catalysismentioning

confidence: 96%

The Contribution of Electrochemistry to the Development of Chemical Kinetics

Laidler

1989

ACS Symposium Series

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“…This has not yet been done for the two systems noted above; however, such data have been reported (15) • C. Construction of an Arrhenius plot of ln(k d ) versus 1/T , followed by application of transition state theory (42)(43)(44), allowed calculation of the enthalpy of activation, H ‡ , and entropy of activation, S ‡ , for the process. Values were H ‡ = +9.9 kcal/mol and S ‡ = −63 cal/K/mol for CD4 antibody-beads and H ‡ = +7.2 kcal/mol and S ‡ = −74 cal/K/mol for CD8 antibodybeads in the first completed run with data as listed in Table 3.…”

Section: Discussionmentioning

confidence: 97%