Abstract
The rate coefficients for OH + CH
3
OH and OH + CH
3
OH (+ X) (X = NH
3
, H
2
O) 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 + CH
3
OH is dominated by the hydrogen atoms abstraction from CH
3
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 + CH
3
OH (8.8 × 10
−13
cm
3
molecule
−1
s
−1
), for OH + CH
3
OH (+ NH
3
) [1.9 × 10
−21
cm
3
molecule
−1
s
−1
] and for OH + CH
3
OH (+ H
2
O) [8.1 × 10
−16
cm
3
molecule
−1
s
−1
] at 300 K. The rate coefficient is at least 8 order magnitude [for OH + CH
3
OH(+ NH
3
) reaction] and 3 orders magnitude [OH + CH
3
OH (+ H
2
O)] are smaller than free OH + CH
3
OH reaction. Our calculations predict that the catalytic effect of single ammonia and water molecule on OH + CH
3
OH 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.