OP-II-3

PP-I-25SYNTHESIS OF ETHYLENE OXIDE IN A MICROREACTOR:ELUCIDATING THE REACTION MECHANISM THROUGH DETAILEDKINETIC MODELLINGJosé Rafael Hernández Carucci 1 , Mauricio Roche 1 , Hongfan Guo 2 ,Johan Wärnå 1 , Kari Eränen 1 , Markku Leskelä 2 , Tapio Salmi 1 , Dmitry Yu. Murzin 11 Laboratory of Industrial Chemistry and Reaction Engineering, Process ChemistryCentre, Åbo Akademi University, Biskopsgatan 8, FI-20500, Turku/Åbo, Finland2 Laboratory of Inorganic Chemistry, Department of Chemistry (A.I.Virtasen aukio 1)P.O. Box 55, FI-00014 University of Helsinki, FinlandEthylene oxide (EO) is one of the most important organic intermediates with anannual global production of ca. 19 million metric tons. EO is produced by theselective partial oxidation of ethylene, with a total heat of reaction between -350 to -550 kJ/mol, causing hot spots and heat removal problems in conventional reactors.The transport of EO to long distances poses a safety risk. Furthermore, shippingcosts are expected to grow in the future. Thus, a tailored, on-site production of EObecomes an attractive option with the aid of suitable, selective heterogeneouscatalysts. This requires, however, advanced reactor technology, in which theclassical problems of scale-up and operability are avoided. Such a technology isprovided by microstructured devices, particularly gas-phase microreactors, which areinherently safe and have very good operability properties [1,2]. Microreactors are stilla relatively novel technology in chemistry, but already many advantages overconventional reactor design have been identified. Many of these advantages arerelated to the issue, that even though the chemistry itself is scale-independent,transport phenomena are not. In microengineered systems, mass and heat transferare intensified: the decrease of the characteristic dimensions lead to the increase ofthe surface-to-volume ratio enhancing the mass and heat transfer between thesurfaces and the fluid. Moreover, the intrinsic safety provided by these reactorsallows the operation under explosive regime, e.g. ethylene in pure oxygen, conditionsnot possible to obtain in conventional laboratory vessels. A lot of research is done oncatalytic gas-phase processes in microdevices, but kinetic modelling is often missing.In this work, we present a systematic approach to a very precise kinetic modelling ofdata obtained from a microreactor. So far, silver supported on alumina has been thecatalyst of choice for the synthesis of EO. However, the recent growing interest ingold-supported catalyst has opened a window of possibilities for many chemical265