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Detailed Program
Paper Number : SY-P03
Time Frame : 12:00~13:30
Presentation Date : Thursday, 27, November
Session Name : Synthesis, Raw Materials & Advanced powder processing
Session Chair 1# : -
Session Chair 2# : -
Catalytic Liquid-phase Oxidation of Acetaldehyde over a Pt/CeO2-ZrO2-SnO2/¥ã-Alumina Catalyst
Mr. Pilgyu Choi
Osaka University
Acetaldehyde is a popular organic compound and is often used as a solvent for paints and adhesives. This compound is soluble in water and is identified as a cancer-causing substance. However, acetaldehyde is contained in a high level in industrial liquid waste from synthetic resin plants. To protect our health and the environment, it is important to remove acetaldehyde in wastewater as much as possible. Liquid-phase oxidation of acetaldehyde using a heterogeneous catalyst is one of the effective purification methods. In addition, useful acetic acid can be produced by selective oxidation of acetaldehyde in a liquid phase. In this study, a Pt/CeO2-ZrO2-SnO2/¥ã-Al2O3 catalyst was prepared for the selective oxidation of acetaldehyde to acetic acid. In this catalyst, the main oxidation catalyst is Pt and ¥ã-Al2O3 is a catalyst support. The CeO2-ZrO2-SnO2 solid solution works as a promoter to facilitate oxidation by supplying active oxygen from inside the bulk due to the oxygen storage and release properties [1]. The CeO2-ZrO2-SnO2 promoter was supported on ¥ã-Al2O3 by a co-precipitation method. The content of the promoter was adjusted to be 16 wt% and the atomic ratio of Ce:Zr:Sn were controlled to be 68:17:15, where the highest oxidation catalysis was obtained for gas-phase oxidation of acetaldehyde [1]. The supported platinum catalyst (Pt/CeO2-ZrO2-SnO2/¥ã-Al2O3) was prepared by impregnating the CeO2-ZrO2-SnO2/¥ã-Al2O3 support with a platinum colloid stabilized with polyvinylpyrrolidone. The amount of Pt in the catalyst was adjusted in the range of 5-10 wt%. After impregnation, the catalyst was dried at 80 ¢®¨¡C for 12 h and then calcined at 500 ¢®¨¡C for 4 h. The catalytic liquid phase oxidation of acetaldehyde was carried out in the air atmosphere in batch mode with mechanically stirring. An aqueous solution of 450 ppm acetaldehyde was poured into the flask and the catalyst (0.2 g) was loaded. The reactor was then cooled in an ice bath at 0 ¢®¨¡C. After the reaction for 2-8 h, the catalyst was separated by centrifugation and the supernatant liquid was analyzed using gas chromatograph mass spectrometry to evaluate the acetaldehyde conversion to acetic acid. Among the catalysts, 6.4wt%Pt/16wt%Ce0.68Zr0.17Sn0.15O2/¥ã-Al2O3 showed the highest acetaldehyde oxidation activity. Figure 1 shows reaction time dependence of residual percentage of acetaldehyde and the selectivity to acetic acid using this catalyst. Acetaldehyde was completely oxidized after the reaction at 0 ¢®¨¡C for 8 h, and the selectivity to acetic acid was as high as 97% after the reaction at 0 ¢®¨¡C for 6 h.
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