Kinetics of Heterogeneous Solvent‐free Liquid Phase Oxidation of Alcohol Using ZrO 2 Catalyst with Molecular Oxygen

Sadiq

2008

Catal Lett

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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.

“…It has been shown earlier that monoclinic zirconia was a more effective catalyst than tetragonal zirconia for alcohol oxidation in solvent free conditions [18,19].…”

Section: Catalyst Preparation and Characterizationmentioning

confidence: 98%

“…Zirconia [17][18][19][20] was prepared using an aqueous solution of zirconyl chloride with the drop wise addition of NH 4 OH for 4 h (pH 10) with continuous stirring. The precipitate was washed with triply distilled water using a Soxhlet's apparatus for 24 h. The Cl -1 test with AgNO 3 was found to be negative.…”

Section: Catalyst Preparation and Characterizationmentioning

confidence: 99%

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

Sadiq

2008

Catal Lett

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“…It is the oxidation of dyestuff in aqueous medium at high temperature (398-593 K) and pressure (0. [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] in the presence of oxygen. However, high temperature and pressure in wet oxidation process appeals high machinery and practical costs which can be reduced using a proper homogeneous or heterogeneous catalyst.…”

Section: Introductionmentioning

confidence: 99%

“…Heterogeneous catalytic wet oxidation is best practice for degradation of dyes in wastewater in which various metal-based catalysts in supported or unsupported form can be used as heterogeneous catalysts. This process has several preferences such as easy separation of catalyst from reaction mixture and recycling of the catalyst [8][9][10][11][12]. Precious metal-based catalysts such as Pt and Pd are sufficiently active toward the oxidative degradation of organic dyes in aqueous medium.…”

Section: Introductionmentioning

confidence: 99%

Oxidative degradation of Methyl Orange catalyzed by lab prepared nickel hydroxide in aqueous medium

Saeed

Adeel

Desalination and Water Treatment

et al. 2016

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A B S T R A C TThis study is focused on oxidative degradation of Methyl Orange, a common azo dye, catalyzed by nickel hydroxide in aqueous solution at 303, 313, 323, and 333 K. Sodium hypochlorite, sodium hydroxide, and nickel sulfate hexahydrate in distilled water were used as starting material for preparation of nickel hydroxide. Pyrex glass batch reactor was used to study the effect of various conditions such as temperature, concentration, agitation, and catalyst dose on catalytic degradation of Methyl Orange in aqueous medium. About 80% Methyl Orange was degraded in 120 min. Experimental data were subjected to kinetic analysis using CurveExpert software. Degradation reaction was taking place according to Langmuir-Hinshelwood mechanism. According to this mechanism, the reactants adsorb at the surface of catalyst in first step followed by reaction between adsorbed reactants in second step. Adsorption of Methyl Orange on surface of catalyst followed Langmuir adsorption isotherm. Apparent activation energy, true activation energy, and heat of adsorption were determined as 13.2, 32.7 and -23.5 kJ mol −1 , respectively.

“…In many cases, aluminaand zirconia-supported metal oxides of precious metals like Pt and Pd have shown high activity for oxidation of alcohols. From the economical point of view, however, using oxides of non-precious transition metals like manganese as heterogeneous catalysts for oxidation of alcohols, using clean oxidants such as molecular oxygen is of great importance [7,8]. Manganese oxide, a non-precious metal oxide, has been used as an oxidation catalyst in several chemical processes, e.g.…”

Section: Introductionmentioning

confidence: 99%

Mixed-valence Manganese Oxide Catalysed Oxidation of Benzyl Alcohol and Cyclohexanol in the Liquid Phase

Progress in Reaction Kinetics and Mechanism

Saeed

Sadiq

et al. 2014

Self Cite

Two types of mixed-valence manganese oxides were synthesised by a mechanochemical process in the solid phase by chemical reaction of manganese(II) chloride and potassium permanganate at room temperature. The prepared catalysts were characterised by surface area and pore size, particle size, XRD analyses, SEM analyses and oxygen content measurements. These oxides were used as catalysts for oxidation of benzyl alcohol and cyclohexanol in the presence of solvent and also in solvent-free conditions using molecular oxygen as oxidant. The oxidation reactions were heterogeneous in nature where the catalysts were separated from the reaction mixture by simple filtration. Reaction took place in two steps according to the Langmuir -Hinshelwood mechanism. Benzyl alcohol/cyclohexanol and oxygen adsorb at the surface of the catalyst in the first step followed by reaction between adsorbed benzyl alcohol/cyclohexanol in second step. 69.8 kJ mol -1 and 140.8 kJ mol -1 were calculated as the activation energy for benzyl alcohol and cyclohexanol in n-octane as the solvent respectively, with values of 65.1 and 76 kJ mol -1 for benzyl alcohol and cyclohexanol in solvent-free conditions respectively.