Effect of ammonia and water molecule on OH + CH3OH reaction under tropospheric condition
Journal
Scientific Reports
Journal Volume
11
Journal Issue
1
Date Issued
2021
Author(s)
Ali M.A
Balaganesh M
Al-Odail F.A
KING-CHUEN LIN
Abstract
The rate coefficients for OH + CH3OH and OH + CH3OH (+ X) (X = NH3, H2O) reactions were calculated using microcanonical, and canonical variational transition state theory (CVT) between 200 and 400?K based on potential energy surface constructed using CCSD(T)//M06-2X/6-311++G(3df,3pd). The results show that OH + CH3OH is dominated by the hydrogen atoms abstraction from CH3 position in both free and ammonia/water catalyzed ones. This result is in consistent with previous experimental and theoretical studies. The calculated rate coefficient for the OH + CH3OH (8.8 × 10?13 cm3 molecule?1?s?1), for OH + CH3OH (+ NH3) [1.9 × 10?21 cm3 molecule?1?s?1] and for OH + CH3OH (+ H2O) [8.1 × 10?16 cm3 molecule?1?s?1] at 300?K. The rate coefficient is at least 8 order magnitude [for OH + CH3OH(+ NH3) reaction] and 3 orders magnitude [OH + CH3OH (+ H2O)] are smaller than free OH + CH3OH reaction. Our calculations predict that the catalytic effect of single ammonia and water molecule on OH + CH3OH reaction has no effect under tropospheric conditions because the dominated ammonia and water-assisted reaction depends on ammonia and water concentration, respectively. As a result, the total effective reaction rate coefficients are smaller. The current study provides a comprehensive example of how basic and neutral catalysts effect the most important atmospheric prototype alcohol reactions. ? 2021, The Author(s).
Type
journal article