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

在气候变化、乙醇价格下降以及乙烯和丙烯的需求和价格上升的背景下，开发用于将乙烯、（生物）乙醇和甲醇转化为“绿色”丙烯和其他烯烃的新的可持续的专用方法是本十年的主要任务。与Braskem公司用于聚合物工业的“绿色”乙烯相比，生产丙烯和后续产品PP、PEG等的新方法引起了相当大的关注。从醇在沸石上的催化直接转化和烃池转化的现状来看，出现了两个主要的经济问题：（i）对于不同的工艺条件和催化剂材料，哪种转化途径促进由甲醇或乙醇生成丙烯的所需产物？(ii)哪种催化剂特性促进了从甲醇、乙醇或两者的混合物选择性生产丙烯的所需转化路线？在一个更科学的角度来看，以下问题将进行更深入的研究：（iii）哪些催化表面反应步骤和相互依赖的动力学是必要的选择性丙烯的形成？(iv)从热力学角度看，哪些工艺路线主要由焓驱动，哪些由熵驱动，哪些由孔的几何形状和形态改变方向？该工作计划分为沸石合成和表征、催化测试和机理评估实验。除了催化剂的固态表征（XRD，NMR，IR，SEM，EDX，ICP-OES，TPD）外，连续模式的催化测试将与吸附动力学（例如Howarth动力学）和详细的烃产物网络（中间体）的复杂机理研究相结合。作为一个专业，新的相互依赖的静态反应链网络的机制的结论，将通过新的混合同位素混乱实验与D 6-乙醇和13 C-甲醇和GC/MS分析研究。尽管目前的讨论，它应该揭示了一个动态的竞争不同的直接和池形成路线丙烯，与完全排除某些路线。此外，实验将揭示具有各自的催化剂失活行为的高度选择性的参数场。基于知识的转化路线控制将能够为工业设计合适的催化剂。就目前的价格发展而言，已经存在对MTP技术（甲醇制丙烯）的需求，并且在未来5-10年内将存在对ETP技术（乙醇/乙烯制丙烯）的经济需求。此外，新的研究指向组合的甲醇和乙醇（或乙烯）转化为烯烃，如丙烯（METO），这表明在产品选择性和催化剂失活的协同效应。这种选择性过程将是科学和经济上的突破。

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.