Kinetics of H abstraction and addition reactions of 2,4,4-trimethyl-2-pentene by OH radical

The kinetics of H abstraction and addition reactions of 2,4,4-trimethyl-2-pentene by OH were determined by traditional and canonical variational transition state theory, with potential energy surfaces calculated at DLPNO-CCSD(T)/cc-pvtz//BHANDHLYP/6-311G(d, p) and CCSD(T)/6-311++G(d, p)//BHANDHLYP/6-311G(d, p) level. In addition, tunneling effects were corrected by zero-curvature and small-curvature and the microcanonical multidimensional tunneling methods. Results reveal that allylic H abstraction, with low energy barrier, dominants H abstraction reactions, which undergoes both indirect and direct channels. Moreover, OH addition reactions with submerged barriers exhibit negative temperature dependence. H abstraction reactions are significant above 750 K, while addition reactions are more important below 400 K.