Hybrid Quantum Mechanical and Molecular Mechanics Study of the SN2 Reaction of CCl4 + OH– in Aqueous Solution: The Potential of Mean Force, Reaction Energetics, and Rate Constants
- 29 February 2012
- journal article
- research article
- Published by American Chemical Society (ACS) in The Journal of Physical Chemistry A
- Vol. 116 (9), 2371-2376
- https://doi.org/10.1021/jp3005986
Abstract
The bimolecular nucleophilic substitution reaction of CCl4 and OH– in aqueous solution was investigated on the basis of a combined quantum mechanical and molecular mechanics method. A multilayered representation approach is employed to achieve high accuracy results at the CCSD(T) level of theory. The potential of mean force calculations at the DFT level and CCSD(T) level of theory yield reaction barrier heights of 22.7 and 27.9 kcal/mol, respectively. Both the solvation effects and the solvent-induced polarization effect have significant contributions to the reaction energetics, for example, the solvation effect raises the saddle point by 10.6 kcal/mol. The calculated rate constant coefficient is 8.6 × 10–28 cm3 molecule–1 s–1 at the standard state condition, which is about 17 orders magnitude smaller than that in the gas phase. Among the four chloromethanes (CH3Cl, CH2Cl2, CHCl3, and CCl4), CCl4 has the lowest free energy activation barrier for the reaction with OH– in aqueous solution, confirming the trend that substitution of Cl by H in chloromethanes diminishes the reactivity.Keywords
This publication has 36 references indexed in Scilit:
- A S N 2 Reaction That Avoids Its Deep Potential Energy MinimumScience, 2002
- Gas phase nucleophilic substitutionInternational Journal of Mass Spectrometry, 2002
- Benchmark ab Initio Energy Profiles for the Gas-Phase SN2 Reactions Y- + CH3X → CH3Y + X- (X,Y = F,Cl,Br). Validation of Hybrid DFT MethodsThe Journal of Physical Chemistry A, 2001
- Solvation Effects on Kinetics of Methylene Chloride Reactions in Sub- and Supercritical Water: Theory, Experiment, and Ab Initio CalculationsThe Journal of Physical Chemistry A, 1998
- Searching for the ylide structure. An ab initio study of the H2O…CCl2 complexChemical Physics Letters, 1996
- Reaction Paths for Aqueous Decomposition of CCl2The Journal of Physical Chemistry, 1996
- Translational Energy Dependence of Cross Sections for Reactions of OH-(H2O)n with CH3Cl and CH3BrThe Journal of Physical Chemistry, 1995
- Ab initio study of the SN2 reactions of hydroxide and hydroperoxide with chloromethaneJournal of the American Chemical Society, 1987
- Nucleophilic displacement vs. proton transfer: the system hydrated hydroxide ion + chloromethane [OH-.cntdot.(H2O)0,1,2 + CH3Cl] in the relative energy range 0.03-5 eVJournal of the American Chemical Society, 1985
- Carbon Dichloride as an Intermediate in the Basic Hydrolysis of Chloroform. A Mechanism for Substitution Reactions at a Saturated Carbon Atom1Journal of the American Chemical Society, 1950