具有调节性酸位的SSZ-39石:选择性甲基胺合成的催化剂
Keyan Jin1, Xiaohe Wang2, Ximing Zhang1
1State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, College of Chemistry, Jilin University, Changchun 130012, China.
Inorganic chemistry
|October 16, 2025
概括
研究人员使用SSZ-39热改进了甲基胺合成,实现了单甲基胺和二甲基胺的90.6%产量. 选择性离子交换优化了酸性地点,增强了这一关键的工业过程.
科学领域:
- 催化剂是一种催化剂.
- 材料科学 材料科学 材料科学
- 化学工程是化学工程的重要组成部分.
背景情况:
- 甲醇氨化对于工业甲基胺生产至关重要 (单甲基胺,二甲基胺,三甲基胺).
- 在工业条件下,像CHA和RHO这样的小孔泽奥利特显示出希望,但在工业条件下,MMA和DMA产量有限 (79.3%).
- 优化酸催化剂是提高甲基胺合成的选择性和产量的关键.
研究的目的:
- 通过甲醇氨化评估SSZ-39热酸对选择性甲基胺合成的性能.
- 研究离子 (Na+) 交换对SSZ-39的催化性能和产品选择性的影响.
- 了解Na+离子交换的机制及其对酸位中和和TMA形成的影响.
主要方法:
- 在工业条件下 (400°C,WHSV 4.3小时−1) 测试H-SSZ-39热 (Si/Al比为5) .
- 在SSZ-39上进行部分Na+交换并评估其对产量的影响.
- 使用固态23Na MQMAS NMR和PXRD与瑞特维尔德精炼来研究Na+离子位置.
- 进行酸位分析和密度功能理论 (DFT) 计算,以探测酸度和离子亲和力.
主要成果:
- 在工业条件下,H-SSZ-39实现了85.9%的MMA和DMA联合收益率 (收益率MMA+DMA).
- 部分Na+交换通过中和有利于TMA形成的强酸位,将MMA+DMA的产量提高到90.6%.
- 核磁共振和PXRD显示,Na+离子在迁移到双重的六个环之前,优先占据八个环 (8MRs).
- DFT计算确定了8MR中的Al-OH组具有最强的Bronsted酸度和最高的Na+亲和力.
结论:
- 与传统的焦油石相比,SSZ-39焦油石显著增强了选择性甲基胺合成.
- 在SSZ-39中的战略Na+交换有效控制了酸度,提高了MMA和DMA的产量.
- 在SSZ-39中,有序的Na+离子交换机制为以岩为基础的系统中合理的催化剂设计提供了一条途径.
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