Inhibitory effect of Zn2+ on the chain-initiation process of cumene oxidation

作者：Chen, Zhicheng; Li, Yuhang^*; Cao, Yonghai; Zhang, Qiao; Yu, Hao; Peng, Feng^*

来源：International Journal of Quantum Chemistry, 2021, 121(21): e26780.

DOI：10.1002/qua.26780

• carbon catalysis
• cumene oxidation
• DFT calculations
• inhibition effect

Carbon nanotubes (CNTs) have excellent catalytic activity in liquid phase reaction, especially in aerobic oxidation of cumene. In previous work, the conversion of cumene was 41.8% and the selectivity of cumene hydroperoxide was 71.5%, which was catalyzed by CNTs. But a small amount of impurity Zn2+ totally blocked up the aerobic oxidation of cumene that catalyzed by CNTs, which is an unexpected discovery. By analyzing the catalytic mechanism of CNTs, the inhibition effect of Zn2+ is locked on the abstraction of H atom from cumene. The inhibition of Zn2+ is confirmed in two effects by density functional theory calculations. First, due to the strongly coordination of active oxygen species (ROS) by Zn2+, the energy barrier of initial reaction increases to 1.90 eV, which is nearly 4 times higher than that of the only ROS promoted-process. Second, the interaction of Zn2+ and RO center dot or ROO center dot to inhibits the chain propagation reaction of free radicals. This work precisely demonstrates that the inhibition effect of Zn2+ on initial reaction of cumene. The most significant thing is that the effect of metallic heteroatoms is not negligible in organic oxidation reaction.

• 单位
  中山大学; 广州大学