Mechanism and Thermal Rate Constants for the Complete Series Reactions of Chlorophenols with H
Citations Over TimeTop 10% of 2009 papers
Abstract
Reactions of chlorophenols with atomic H are important initial steps for the formation of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in incinerators. Detailed insight into the mechanism and kinetic properties of crucial elementary steps is a prerequisite for understanding the formation of PCDD/Fs. In this paper, the complete series reactions of 19 chlorophenol congeners with atomic H have been studied theoretically using the density functional theory (DFT) method and the direct dynamics method. The profiles of the potential energy surface were constructed at the MPWB1K/6-311+G(3df,2p)//MPWB1K/6-31+6(d,p) level. Modeling of the PCDD/Fs formation requires kinetic information aboutthe elemental reactions. The rate constants were deduced over a wide temperature range of 600-1200 K using canonical variational transition-state theory (CVT) with small curvature tunneling contribution (SCT). The rate-temperature formulas were fitted for the first time. This study shows that the substitution pattern of the phenol has a significant effect on the strength and reactivity of the O-H bonds in chlorophenols. Intramolecular hydrogen bonding plays a decisive role in determining the reactivity of the O-H bonds for ortho-substituted phenols.
Related Papers
- → Potential energy surface for a seven-atom reaction. Thermal rate constants and kinetic isotope effects for CH4+OH(2000)74 cited
- → Analytical potential energy surface for the CH4+O(3P)→CH3+OH reaction. Thermal rate constants and kinetic isotope effects(2000)62 cited
- → Quantum Variational Transition State Theory for Hydrogen Tunneling in Enzyme Catalysis(2012)18 cited
- → Dynamic isotope effect on the product energy partitioning in CH2OH+→CHO++H2(1998)11 cited
- Quantum Variational Transition State Theory for Hydrogen Tunneling in Enzyme Catalysis B(2012)