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

二甲氧基甲烷（DMM）及其长链同源物甲氧基醚是潜在的柴油添加剂或清洁燃烧的替代品。将一小部分DMM（约15%）混合到传统柴油燃料中，由于其特殊的分子结构具有高氧含量和无C-C键的特点，已经可以显著减少80%的烟灰形成。传统的DMM合成是通过甲醇氧化制甲醛（FA），然后FA与甲醇缩合制DMM。虽然已有的路线具有较高的催化性能和工艺成熟度，但其主要缺点是在甲醇氧化成FA的过程中有价值的H2作为水的损失，从而导致H2的利用效率较低。最近，我们在固定床连续流反应器中描述了Cu/Hβ催化剂上气相甲醇脱氢非氧化生产DMM的方法。可以强调Cu氧化态和金属与酸位的比例的关键作用，但作为知识驱动的催化剂优化基础的活性位点的性质仍然未知，并且发生了严重的催化剂失活。本项目旨在了解Cu/Hβ在甲醇非氧化脱氢制DMM过程中活性位点的性质，并对催化剂进行合理优化。因此，该研究将全面表征Cu/脱铝Hβ催化剂，并设计Sn加入Cu/脱铝Hβ催化剂，旨在提高长期实验中的活性和稳定性。

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.