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166d

Electrochemical Oxidation and Mineralisation of Acetaldehyde

M. Ernst1, Wolfgang Gangl1, M. Siebenhofer1, E. Ahn2, T. Hilber2, and Rolf Marr1. (1) University of Technology Graz, Department of Chemical Engineering and Environmental Technology, Inffeldgasse 25/C/II, Graz, 8010, Austria, (2) BDI Anlagenbau GmbH, Parkring 18, Grambach, A-8074, Austria

Temperature, electrolyte composition, electrolyte concentration, current density and electrocatalysis determine yield and product selectivity of electrochemical reactions. The correct choice of these parameters determines the magnitude of oxidation and mineralisation of acetaldehyde. Due to the chemical resistivity and excellent catalytic properties platinum and its alloys are recommended for electrochemical oxidation of acetaldehyde. Beside the desired oxidation to acetic acid, the carbon-carbon bond of acetaldehyde is cleaved in side reactions causing generation of carbon monoxide, which then accumulates on the electrode surface and poisons the surface area. Target of this project was to investigate oxidation of acetaldehyde on diamond coated electrodes and to quantify undesirable side reactions. Depending on the operation conditions acetic-, formic-, glycolic- and oxalic acid are formed. Expectedly carbon monoxide poisoning is not observed. The dependence of yield, product selectivity and current efficiency on the operation conditions temperature, concentration, residence time and current density was quantified for process modelling and optimisation.