School of Chemical Engineering, Dalian University of Technology, Dalian 116024, China.
Dalton Trans. 2019 Nov 19;48(45):16974-16985. doi: 10.1039/c9dt02945a.
Herein, we have studied the crystallization of zeolite omega by the solid-state transformation of TMA-magadiite at 100 °C for 12 h. The samples prepared at different times were subjected to XRD, SEM, IR, Raman and solid MAS NMR analyses to investigate the crystallization behaviors and changes in the medium-range structure during the synthesis process and a comprehensive mechanism was proposed. It has been demonstrated that the 5Rs and 6Rs in magadiite are partially retained in the system and participate in the growth of zeolite omega. The 4Rs were formed after heating for 4 h. The synthesis time of the zeolite omega using this method is shorter than that using the magadiite hydrothermal conversion method (about 72 h), because special composition building units, which have similarities to the structure of zeolite omega, were formed and adsorbed on the surface of the TMA-magadiite, and then provided a growth surface for the synthesis of targets. In addition, recycling the waste mother liquid produced in the preparation of the precursor was done to achieve the low cost and green synthesis. Finally, several factors influencing the reaction are discussed.
在此，我们通过在 100°C 下将 TMA-镁碱沸石进行固态转化 12 小时的方法来研究沸石 ω 的结晶。对不同时间制备的样品进行了 XRD、SEM、IR、Raman 和固体 MAS NMR 分析，以研究合成过程中的结晶行为和中程结构的变化，并提出了一个综合的机理。结果表明，镁碱沸石中的 5Rs 和 6Rs 部分保留在体系中并参与了沸石 ω 的生长。4Rs 在加热 4 小时后形成。与使用镁碱沸石水热转化法（约 72 小时）相比，使用该方法合成沸石 ω 的时间更短，因为形成了与沸石 ω 结构相似的特殊组成构建单元，并吸附在 TMA-镁碱沸石表面，然后为目标物的合成提供了生长表面。此外，还对废母液进行了循环利用，以实现低成本和绿色合成。最后，讨论了影响反应的几个因素。
