Investigation of the direct catalytic conversion of methanol and ethanol to propylene

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In the context of climate change, dropping ethanol price and rising demand and price for ethylene and propylene, the development of new sustainable on-purpose methods for conversion of ethylene, (bio-)ethanol and methanol to “green” propylene and other olefins is a major task for this decade. Compared to “green” ethylene by Braskem for polymers industry, new methods to produce propylene and follow-up products for PP, PEG etc. have attracted considerable attention.From the current state of catalytic direct and hydrocarbon pool conversion of alcohols on zeolites, two major economic questions arise: (i) For different process conditions and catalyst materials, which conversion routes promote the desired product formation of propylene from methanol or ethanol? (ii) Which catalyst properties promote the desired conversion routes to a selective production of propylene from methanol, ethanol or both in mixture?In a more scientific point of view, the following questions will be investigated more deeply: (iii) Which catalytic surface reaction steps and which interdependent kinetics are necessary for a selective propylene formation? (iv) From thermodynamics, which process routes are dominantly driven by enthalpy, which by entropy and which are re-directed by pore geometry and morphology?The work program is splitted into zeolite synthesis and characterization, catalytic testing and mechanistic evaluation experiments. Beside solid-state characterization of catalysts (XRD, NMR, IR, SEM, EDX, ICP-OES, TPD), catalytic testing in a continuous mode will be combined with sophisticated mechanistic studies of adsorption kinetics (e.g. Howarth kinetics) and detailed hydrocarbon product networks (intermediates). As a specialty, new interdepending mechanistic conclusions of static reaction chain networks will be investigated by new mixed isotope scrambling experiments with D6-ethanol and 13C-methanol and GC/MS analysis. Despite to current discussions, it should reveal a dynamic competition of different direct and pool formation routes to propylene, in contrast to total exclusion of certain routes. Furthermore, the experiments will reveal highly selective parameter fields with respective deactivation behavior of catalysts. The knowledge-based control of the conversion routes will enable to design suitable catalysts for industry.With respect to current price developments, there is already a need for MTP technologies (methanol-to-propylene) and there will be an economic need for ETP technologies (ethanol/ethylene-to-propylene) within the next 5-10 years. Furthermore, new investigations direct to a combined methanol and ethanol (or ethylene) conversion to olefins, such as propylene (METO), which show synergistic effects in product selectivity and catalyst deactivation. Such a selective process would be a scientific and economic breakthrough.