Inhibitory
effect of Zn2+ on the chain-initiation process ofcumene oxidation
Zhicheng Chena, Yuhang Li*c, Yonghai
Caob, Qiao Zhanga, Hao
Yub and Feng Peng*a
a School of Chemistry and Chemical Engineering,
Guangzhou University, Guangzhou 510006, China.
b School of Chemistry and Chemical Engineering, South
China University of Technology, Guangzhou 510640, China
c School of
Chemistry, Sun Yat-sen University,
Guangzhou 510275, China
* Corresponding author, E-mail:
liyh@mail.sysu.edu.cn
(Y. Li);
fpeng@gzhu.edu.cn (F. Peng)
Abstract: 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 (DFT) calculations. Firstly, 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. Secondly, the
interaction of
Zn2+ and RO· or
ROO· 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.
Keywords: carbon catalysis; cumene oxidation; inhibition
effect; DFT calculations