A metal-free aerobic oxidation of nitrotoluenes catalyzed by N,N',N″-trihydroxyisocyanuric acid (THICA) and a novel approach to the catalyst.
A metal-free catalytic system with N,N',N″-trihydroxyisocyanuric acid (THICA) as the catalyst for the oxidation of nitrotoluenes is introduced, and a novel Pd-free approach for the synthesis of THICA was developed. In a solution of acetic acid, THICA and concentrated nitric acid, nitrotoluenes especially polynitrotoluenes such as 2,4,6-trinitrotoluene (TNT), were converted into the desired carboxylic acids under 0.2 MPa of O(2) at 100°C with yields up to 99%. THICA was synthesized from N-hydroxyphtalimide through a four-step synthesis in a total yield of 46%. A possible mechanism of this catalytic process was proposed where NO(2) and nitric acid first induced a radical of THICA, which then abstracts a hydrogen atom from the methyl on the aromatic ring to form a benzyl radical. This radical then initiates subsequent reactions. The production of the benzyl radical was supported by ESR measurements.
Wang
Kai
K
School of Chemical Engineering and the Environment, Beijing Institute of Technology, Beijing 100081, China.
Zhou
Zhiming
Z
School of Chemical Engineering and the Environment, Beijing Institute of Technology, Beijing 100081, China; State Key Laboratory of Explosion Science and Technology, Beijing Institute of Technology, Beijing 100081, China. Electronic address: zzm@bit.edu.cn.
Song
Jinhong
J
School of Chemical Engineering and the Environment, Beijing Institute of Technology, Beijing 100081, China.
Bi
Lixue
L
School of Chemical Engineering and the Environment, Beijing Institute of Technology, Beijing 100081, China.
Shen
Ning
N
School of Chemical Engineering and the Environment, Beijing Institute of Technology, Beijing 100081, China.
Wu
Yukai
Y
School of Chemical Engineering and the Environment, Beijing Institute of Technology, Beijing 100081, China.
Chen
Fuxue
F
School of Chemical Engineering and the Environment, Beijing Institute of Technology, Beijing 100081, China.
Wen
Hongliang
H
School of Chemical Engineering and the Environment, Beijing Institute of Technology, Beijing 100081, China.
D002384:Catalysis; D008670:Metals / Q000737:chemistry; D010084:Oxidation-Reduction; D010100:Oxygen / Q000737:chemistry; D012997:Solvents / Q000737:chemistry; D014227:Triazines / Q000737:chemistry*; D014303:Trinitrotoluene / Q000737:chemistry*
D008670:Metals; C555350:N,N',N''-trihydroxyisocyanuric acid; D012997:Solvents; D014227:Triazines; D014303:Trinitrotoluene; D010100:Oxygen