The commercialization of the methanol-to-olefins (MTO) reaction has made significant progress in recent years. As the main products of the MTO reaction, the separation of C3H6 and C2H4 is of important significance for the chemical industry. This study introduces Amino-Functionalized Pillar-Layered Co6-Cluster Metal-Organic Framework (PL-Co-MOF), an innovative ultra-microporous framework synthesized using 4-(4-carboxy-N-(4-carboxyphenyl)anilino)benzoic acid (NTA), 2-aminopyrazine (NH2-Pyz), and cobalt salts under solvothermal conditions. The X-ray diffraction analysis was employed to confirm the detailed structure and phase purity of PL-Co-MOF. The calculated molecular electrostatic potential matches the interaction of the framework and MTO gas guest. The experimental data demonstrate that PL-Co-MOF exhibits a significantly higher adsorption of C3H6 in comparison to C2H4 at 298 K and 10 kPa. This evidence supports the exceptional selectivity of PL-Co-MOF towards a 50/50 C3H6/C2H4 ratio, which is 8.61. Breakthrough experiments confirm its effectiveness in separating C2H4 from C3H6/ C2H4 mixtures, with C2H4 elution time reached 46.6 min/g. Theoretical calculations reveal that the origin of excellent separation performance of a PL-Co-MOF is due to the oxygen sites in the Co6O6 clusters and the amino groups in NH2-Pyz; In-situ FTIR of gases further verifies the absorption sites of the Co6O6 clusters and the amino groups in theoretical calculation results, which complementarily explains the real separation process of MTO gas molecules and frameworks. This highlights the importance of rational construction of MOFs for achieving efficient multicomponent separation. This work aims to advance adsorption separation technology and improve the gas purity of the MTO process.

中文翻译：

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用于 MTO 工艺气体净化的氨基功能化柱层 Co6O6 团簇 MOF 的合理设计


近年来，甲醇制烯烃 （MTO） 反应的商业化取得了重大进展。C3H6 和 C2H4 作为 MTO 反应的主要产物，分离对化工具有重要意义。本研究介绍了氨基功能化柱层 Co6 簇金属有机框架 （PL-Co-MOF），这是一种在溶剂热条件下使用 4-（4-羧基-N-（4-羧基苯基）苯胺基苯甲酸 （NTA）、2-氨基吡嗪 （NH2-Pyz） 和钴盐合成的创新型超微孔框架。采用 X 射线衍射分析确认 PL-Co-MOF 的详细结构和相纯度。计算出的分子静电势与框架和 MTO 气体客体的相互作用相匹配。实验数据表明，在 298 K 和 10 kPa 下，与 C2H4 相比，PL-Co-MOF 对 C3H6 的吸附率明显更高。该证据支持 PL-Co-MOF 对 50/50 C3H6/C2H4 比率（即 8.61）的特殊选择性。突破性实验证实了其从 C3H6/C2H4 混合物中分离 C2H4 的有效性，C2H4 洗脱时间达到 46.6 min/g。理论计算表明，PL-Co-MOF 优异分离性能的来源是由于 Co6O6 簇中的氧位点和 NH2-Pyz 中的氨基;气体原位 FTIR 在理论计算结果中进一步验证了 Co6O6 团簇和氨基的吸收位点，补充解释了 MTO 气体分子和框架的真实分离过程。这凸显了合理构建 MOF 对于实现高效多组分分离的重要性。这项工作旨在推进吸附分离技术并提高 MTO 工艺的气体纯度。