Oxymethylene dimethyl ethers (OME_x oligomers with the chain length x) present a promising emission reducing diesel additive, which can potentially be produced based on renewable resources. In this work, the OME_x synthesis catalysed by zeolites was investigated starting from paraformaldehyde and methanol. The catalytic performance of zeolites with different framework types (BEA, FAU, MFI, MOR) and various Si/Al ratios was comparatively studied. The zeolites were characterised by means of NH₃‐TPD, ICP‐OES, XRD and N₂ physisorption. A relationship between catalytic activity and Si/Al ratio was established demonstrating the highest turnover frequency for zeolites with high Si/Al ratios. HZSM‐5 114 with a TOF of 3375 mol_OME3–5 mol_AcidSites⁻¹ h⁻¹ was determined as the best‐performing zeolite which indicates that the OME_x synthesis requires a moderately strong acid strength.

中文翻译：

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系统地筛选具有各种骨架和Si / Al比的沸石以识别OME合成中的最佳酸强度

甲醛二甲基醚（链长为x的OME _x低聚物）是一种很有希望的减排柴油添加剂，可以潜在地基于可再生资源生产。在这项工作中，研究了从多聚甲醛和甲醇开始的沸石催化的OME _x合成。比较研究了不同骨架类型（BEA，FAU，MFI，MOR）和各种Si / Al比的沸石的催化性能。通过NH ₃ -TPD，ICP-OES，XRD和N ₂物理吸附来表征沸石。建立了催化活性和Si / Al比之间的关系，表明具有高Si ​​/ Al比的沸石的最高周转频率。HZSM-5114，TOF为3375摩尔_OME3–5  mol _AcidSites ^-1  h ^-1被确定为性能最佳的沸石，这表明OME _x合成需要中等强度的酸强度。