The G2 level were performed to get insight into the reaction mechanism. The results of the calculations also enable an estimation on the reaction energetics plus the molecular properties from the structures taking part within the reaction mechanism. The calculated values of the enthalpy of formation with the reactants and products are in pretty fantastic agreement with the reported values estimated experimentally. All of the reactions studied are exothermic processes, together with the calculated values from the reaction enthalpy at 298 K of -5.9, -9.0 and -14.2 kJ mol -1 for CH 3 F + Cl, CH 3 Br + Cl and CH three Cl + Cl, respectively. The calculated profiles from the potential energy surface on the reaction systems show that the mechanism on the reactions studied is complicated plus the H-abstraction proceeds by means of the formation of intermediate complexes. The multi-step reaction mechanism consists of two – in the case of CH3F + Cl – and of 3 for CH3Cl+Cl and CH3Br + Cl elementary steps. The heights of your power barrier connected towards the H-abstraction are of eight?0 kJ mol-1, the lowest value corresponds to CH3Cl + Cl as well as the highest 1 to CH3F + Cl.Formula of 98642-15-0 These low power barriers lead to the higher values of the price constants, of 10-J Mol Model (2013) 19:1489?cm3molecule-1s-1 at area temperature.Price of 61302-99-6 The rate constants have been calculated employing the theoretical process based around the RRKM theory and also the simplified version from the statistical adiabatic channel model [57].PMID:24220671 However, the values of your rate continual calculated at the low temperatures (i.e., beneath 1000 K) making use of the conventional transition state theory are extremely close to these derived in the precise calculations. The calculated values of your rate constants nicely describe the kinetics of CH3X + Cl reactions systems. An in particular superior agreement between the calculated and reported values on the rate constant has been reached for the reaction CH3Cl + Cl. The calculated values of your rate constant for this reaction certainly form the trend line in the experimentally estimated benefits. The derived kinetic expression describes quite well the kinetics of CH3Cl + Cl within the whole variety of the experimental measurements of 250?000 K, with an accuracy a minimum of no worse than the one given by several kinetic data evaluations. Inside the temperature range of 250?00 K, the kinetic parameters derived theoretically also allow a quantitative description with the reaction kinetics of CH3F + Cl and CH3Br + Cl. In the higher temperatures, the agreement in between the calculated and experimental values with the rate constants for these reactions deteriorates due to the fact the calculated values of k(CH3F+Cl) and k(CH3Br+Cl) slightly exceed the experimental findings. This can be an impact from the treatment on the lowest degrees of freedom of TS1F and TS1Br because the harmonic vibrations. The substitution of a hydrogen atom by deuterium alterations the physical properties from the reactant molecules, which may well basically have an influence around the kinetics in the reactions studied. The results on the reaction path calculations show that the D-abstraction is related with the energy barrier of 5 kJ mol-1 higher than the H-abstraction from the corresponding non-deuterated reactant molecule. The calculated values from the rate constants k(CD3X+Cl) are distinctly decrease compared together with the values of their counterparts, k(CH3X+Cl), especially at low temperatures. Alternatively, the values derived in this study plus the reported values of KIE [21] calculated in the various levels of theory are greater t.
