Stability and Reactivity of a Polyoxymethylene Dimethyl Ether over Typical Catalysts for Diesel Emission Control

• Published in: Topics in catalysis 2023-08, Vol.66 (13-14), p.797-803
• Main Authors: Elsener, Martin, Jacob, Eberhard, Ferri, Davide, Kröcher, Oliver
• Format: Article
• Language: English
• Subjects: Ammonia; Automotive parts; Catalysis; Catalysts; Catalytic converters; Characterization and Evaluation of Materials; Chemistry; Chemistry and Materials Science; Cold starts; Decomposition reactions; Diesel fuels; Dimethyl ether; Emissions control; Engine tests; Ethers; Exhaust systems; Formaldehyde; Formic acid; Industrial Chemistry/Chemical Engineering; Low temperature; Methanol; Original Paper; Oxidation; Palladium; Pharmacy; Physical Chemistry; Platinum; Temperature; Titanium dioxide; Tungsten oxides; Vanadium pentoxide
• ISSN: 1022-5528; 1572-9028
• DOI: 10.1007/s11244-022-01725-z

Polyoxymethylene dimethyl ethers (OME) produced from methanol are considered as potential substitutes of Diesel fuel. Emissions of formaldehyde and other components have been observed, particularly under cold-start conditions in engine test-bench experiments with OME fuel. In this study, the reactivity of OME 3 (CH 3 O(CH 2 O) 3 CH 3 ) and its decomposition products was studied in the temperature range 80–450 °C in a model gas test bench over V 2 O 5 /WO 3 /TiO 2 and Cu-CHA SCR catalysts, a platinum-coated V 2 O 5 /WO 3 /TiO 2 ammonia slip catalyst (ASC) and two diesel oxidation catalysts (DOC), based on platinum and platinum-palladium. Already at 80 °C, OME 3 was largely hydrolyzed to methanol and formaldehyde over all catalysts. At temperatures above 150 °C, V 2 O 5 /WO 3 /TiO 2 oxidized methanol and formaldehyde to CO via formic acid as intermediate. The platinum ASC showed a similar behavior but oxidized the decomposition products to CO 2 . Whereas Cu-CHA hydrolyzed OME 3 quantitatively to methanol and formaldehyde, it did not show oxidation activity in the studied temperature range. The data indicate that the release of significant amounts of OME from a catalytic converter can be virtually ruled out under cold start conditions, but also that low temperature hydrolysis produces formaldehyde and methanol emissions.