Advanced Catalysts design for Dimethoxymethane Synthesis by Gas-phase Non-oxidative Dehydrogenation of Methanol

二甲氧基甲烷（DMM）及其长链同系物甲醛醚是潜在的柴油添加剂或清洁燃烧的替代品。混合一小部分DMM（约。15%）转化为常规柴油燃料，由于具有高氧含量和无C-C键的特殊分子结构，已经能够将碳烟形成显著减少80%。常规的DMM合成通过甲醇氧化成甲醛（FA），然后FA与甲醇缩合成DMM来进行。尽管具有高催化性能和工艺成熟度，但现有路线的主要缺点在于在甲醇氧化为FA期间有价值的H2作为水损失，从而导致H2的利用效率低。最近，我们在固定床连续流动反应器中，描述了在Cu/Hβ催化剂上甲醇气相脱氢非氧化制备DMM。可以强调Cu氧化态和金属与酸位点的比率的关键作用，但是作为知识驱动的催化剂优化的基础的活性位点的性质仍然未知，并且发生显著的催化剂失活。本项目旨在深入了解甲醇非氧化脱氢制DMM反应中Cu/Hβ催化剂活性中心的性质，并对催化剂进行合理优化。因此，该研究将理解Cu/脱铝Hβ催化剂的综合表征以及旨在提高长期实验期间的活性和稳定性的Sn掺入的Cu/脱铝Hβ催化剂的设计。

Dimethoxymethane (DMM) and its long-chain homologues oxymethylene ethers present potential drop-in diesel additives or alternatives for cleaner combustion. Blending a small fraction of DMM (ca. 15%) into conventional diesel fuels can already enable a significant reduction in soot formation by 80% owing to the special molecular structure featuring high oxygen content and no C-C bond. Conventional DMM synthesis proceeds via methanol oxidation to formaldehyde (FA) followed by condensation of FA with methanol to DMM. Despite the high catalytic performances and process maturity, the major drawback of established routes lies in the loss of valuable H2 as water during methanol oxidation to FA, thus leading to a low utilization efficiency of H2. Recently, we described the non-oxidative production of DMM by gas-phase methanol dehydrogenation over Cu/Hβ catalysts in a fixed-bed continuous flow reactor. The crucial role of Cu oxidation state and the ratio of metal and acid sites could be emphasized but the nature of the active sites as basis for knowledge driven catalyst optimization remained unknown and significant catalyst deactivation occurred. This project aims at gaining insights into the nature of the active sites of Cu/Hβ in the non-oxidative methanol dehydrogenation to DMM and rational optimization of the catalyst. Hence, the study will comprehend a comprehensive characterization of the Cu/dealuminated Hβ catalyst and the design of Sn incorporated Cu/dealuminated Hβ catalysts aiming for enhanced activity and stability during long-term experiments.