Oxidation of toluenes to benzoic acids by oxygen in non-acidic solvents
Fan Yang, Jing Sun, Rui Zheng, Wenwei Qiu, Jie Tang* and Mingyuan He
*Center for the Chemistry of Ionic Liquids, Department of Chemistry, East
China Normal University, Shanghai 200062, China, Email: jtang
chem.ecnu.edu.cn
F. Yang, J. Sun, R. Zheng, W. Qiu, J. Tang, M. He, Tetrahedron, 2004, 60, 1225-1228.
DOI: 10.1016/j.tet.2003.11.079
Abstract
The oxidation of substituted toluenes by molecular oxygen to the corresponding substituted benzoic acids using Co(C18H35O2)2/NH4Br or Co(OAc)2/NaBr/AcOH as catalysts in the presence of a radical initiator in non-acidic solvents was investigated.
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Details
The study investigates the oxidation of substituted toluenes to benzoic acids using molecular oxygen in non-acidic solvents. The research, conducted by Fan Yang and colleagues at East China Normal University, explores the use of Co(C18H35O2)2/NH4Br (system A) and Co(OAc)2/NaBr/AcOH (system B) as catalysts in the presence of a radical initiator like AIBN. The oxidation process was carried out under atmospheric pressure in solvents such as dichlorobenzene, chlorobenzene, and bromobenzene. The results showed that system B was more efficient, requiring lower temperatures (110°C) compared to system A (150°C), and provided higher yields for most substrates. For instance, p-bromotoluene achieved a 92% yield with system A and 90% with system B. The study also highlighted the compatibility of cyano groups and the influence of substitution positions on yields. The oxidation of p-xylene resulted in a 96% yield of p-phthalic acid. The research presents a practical and environmentally friendly method for producing substituted benzoic acids, which are valuable in chemical and pharmaceutical industries. The findings emphasize the importance of catalyst choice and reaction conditions in optimizing yields and efficiency.
Key Words
Oxidation, Toluenes, Benzoic acids, Oxygen
ID: J72-Y2004-270
