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

Abstract

Copper manganese oxides (Cu-Mn oxides) were prepared by coprecipitation method and characterized by several techniques, such as X-ray powder diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy and Temperature-programmed reduction (TPR). Catalytic activities of the Cu-Mn oxides were tested by the oxidation of toluene with molecular oxygen in liquid phase and solvent-free conditions. The molar ratio of Cu:Mn in catalyst was optimized to be 1:1 and thus the corresponding crystalline material was designated as Cu 1.5 Mn 1.5 O 4 .

Hydrotalcite derived (Cu, Mn)–Mg–Al metal oxide systems doped with palladium as catalysts for low-temperature methanol incineration

“…A similar result was reported by Kovanda et al (2005). It should be noted that the reduction peak of Cu-Mn-Mg-Al was shifted to higher temperatures comparing to Cu(5)-Mg-Al counterpart, indicating that MnO x retarded the CuO reduction (Li et al, 2006).…”

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

“…The reaction mixture was filtered to remove the catalyst and analyzed. The changes in the concentration of toluene and its products benzyl alcohol, benzaldehyde, benzoic acid, benzyl benzoate, trans-stilbene and methyl biphenyl carboxylic acid were monitored by UV-VIS spectroscopy, gas chromatography and thin layer chromatography [15,16,21,22]. Thin layer chromatographic analysis was carried out using standard chromatographic plates (Merck) with silica gel 60 F 254 support (Merck, TLC: 105,554 and PLC: 113,793).…”

“…Comparison of these results with other solvent free systems shows that Pt/ZrO 2 is very effective catalyst for toluene oxidation. Higher conversions are achieved at considerably lower temperatures and pressure than other solvent free systems [11][12][13][14][15][16]. The catalyst is used with out any additive or promoter.…”

“…Air was used as oxidant (3.5 MPa). The highest conversion (45.1%) was achieved with manganese substituted aluminum phosphate with high benzoic acid selectivity (83.4%) at 150°C in 16 h. Li et al [15,16] have also reported manganese oxide and copper manganese oxide to be active catalysts for toluene oxidation to benzoic acid in solvent free conditions with molecular oxygen (1.0 MPa) at 190-195°C. Recently it was observed in this laboratory [17] that when toluene was used as a solvent for benzyl alcohol (BzOH) oxidation by molecular oxygen at 90°C in the presence of Pt/ZrO 2 as catalyst, benzoic acid was obtained with 100% selectivity.…”

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

“…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.…”