(27e) Kinetic Investigation of H2O2 Synthesis by Controlled H2/O2 Reaction in a Microchannel Reactor

Hydrogen peroxide was formed in a packed-bed microreactor in a three-phase process involving the direct combination of hydrogen and oxygen over a solid catalyst and with the hydrogen peroxide dissolved in a liquid solvent. Hydrogen and air were combined in all proportions, including explosive regime, over platinum group catalyst supported on various oxides. The ultimate goal of the work presented here is to determine the intrinsic kinetics of the direct combination (DC) reaction in the packed-bed microchannel reactor. The DC process comprises multiple reactions involving formation of hydrogen peroxide, formation of water, and consumption of peroxide either by reduction or decomposition. The strategy for determining the overall kinetics of this reaction is to determine the rate expressions for each constituent reaction individually and then to combine the expressions into an overall rate law. Experimental results and calculations showed that the reaction rate is controlled by intrinsic kinetics. Rate expressions for the reduction of hydrogen peroxide by hydrogen, and for the formation of hydrogen peroxide are determined as two of the steps toward determining the kinetics of the overall DC reaction.