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Liquid-phase oxidation of toluene by molecular oxygen over copper manganese oxides

“…However, liquid-phase oxidation is easy to operate and to achieve high selectivity under the relatively mild reaction conditions. Many efforts have been made to improve the efficiency of toluene oxidation in liquid phase through the addition of Mn ions or the use of supercritical CO 2 solvent [10][11][12][13], NHPI/Co(Ac) 2 AE4H 2 O was reported as a catalytic system of oxidation of toluene in acetic acid [14,15], However, most investigations still focus on homogeneous systems, and volatile solvents employed are all the same. In contrast, by employing heterogeneous catalysts in liquid-phase oxidation of toluene, especially without a solvent, those drawbacks could be overcome, and the process would be more environmentally friendly.…”

Liquid-phase oxidation of toluene by molecular oxygen over copper manganese oxides

“…However, liquid-phase oxidation is easy to operate and to achieve high selectivity under the relatively mild reaction conditions. Many efforts have been made to improve the efficiency of toluene oxidation in liquid phase through the addition of Mn ions or the use of supercritical CO 2 solvent [10][11][12][13]. NHPI/Co(Ac) 2 AE4H 2 O was reported as a catalytic system of oxidation of toluene in acetic acid [14,15].…”

Highly Efficient Oxidation of Toluene to Benzoic Acid Catalyzed by Manganese Dioxide and N-Hydroxyphthalimide

“…Under ambient conditions, the oxidation of toluene in the presence of NHPI (10 mol%) and Co(OAc) 2 (0.5 mol%) in acetic acid solution for 20 h produced benzoic acid in 81% yield [23]. This method avoided the use of bromide accelerator which had been proved to be the reason of equipment corrosion in current industrial process [7]. Continuous investigations have shown that NHPI has very highly catalytic efficiencies even under mild conditions in the aerobic oxidation of a wide variety of organic substrates [24][25][26][27][28].…”

“…For obtaining the high or complete conversion of toluene, this process was operated mostly under stringent conditions including high temperatures (around 200°C) and pressures (around 10 atm), meanwhile, it suffered from low energy efficiencies and low selectivity as well as generation of environmentally hazardous waste and byproducts of decarboxylation and over oxidation [2][3][4][5]. Various studies on this process had been performed to optimize the operating conditions in order to improve its selectivity and minimize the over oxidation, however, the reaction temperatures still were as high as over 150°C and the conversions were kept low [6][7][8][9]. Therefore, a major attention in this field is to find reaction pathways that afford benzoic acid with high selectivity at high conversion of toluene.…”