Oxidation of Toluene to Benzoic Acid Catalyzed by Platinum Supported on Zirconia in the Liquid Phase-Solvent Free Conditions

Abstract

Toluene oxidation over platinum supported on zirconia under solvent free conditions in a batch reactor was studied in the temperature range 60-90°C. Molecular oxygen was used as oxidant. The catalyst was highly active and selective for benzoic acid formation. Some conversion to benzyl benzoate, trans-stilbene and methyl biphenyl carboxylic acid was also observed when the reaction was studied for [3 h. The reaction is taking place at considerably lower temperature than the reported solvent free oxidation reactions of toluene.

Phenyl modification of Mn‐containing mesoporous silica and catalytic oxidation of toluene

“…However, one of the major problems of homogenous catalysis is the difficult separation of the catalyst from the reaction mixture, which is often energy intensive and generates a large volume of waste 10. As a result of the easy recovery of the catalyst from products and solvent‐free reaction conditions, heterogeneous catalytic oxidation has attracted much attention in recent years 11–16. For example, single‐site solid catalyst FeAlPO‐5 was used for toluene oxidation in high yield by Raja and Thomas 17.…”

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

“…Currently, it was produced by the catalytic aerobic liquid oxidation of toluene in acetic acid solution using cobalt salts as catalyst and bromide as accelerator. 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].…”

“…The vapor-phase oxidations of toluene [10][11][12], especially catalyzed by V-oxides supported on TiO 2, had been investigated, showing the advantage of separation and so on, but the highly specialized equipment and high temperature were required. The attempts using heterogeneous catalyst [3,4,[13][14][15][16][17] and supercritical fluids as reaction mediators [5,[18][19][20] had also been made to make this oxidation more environmentally benign. However, the low catalytic activities and expensive solvents limited the application of these methods.…”

Selective oxidation of aromatic hydrocarbons by potassium and phosphorous-modified iron oxide–silica nanocomposite

“…Active catalysts for the selective side chain oxidation of alkyl aromatic compounds have been used in the liquid phase, gas phase [4] and supercritical media [5,6]. The selective liquid phase oxidation can be conducted both homogeneously and heterogeneously involving mostly metals with two or more stable oxidation states, typically under acidic conditions.…”

“…The selective liquid phase oxidation can be conducted both homogeneously and heterogeneously involving mostly metals with two or more stable oxidation states, typically under acidic conditions. Most catalytic systems are based on Co [7], Pt [6] and Cu [8]. Nevertheless, these catalytic oxidation reactions still require harsh conditions in industry [9].…”