Han Ai-Jie, Guo Juan, Yu Hui, Zeng Yu, Huang Yue-Fang, He He-Yong, Long Ying-Cai
Department of Chemistry and Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Fudan University, Shanghai 200433, P.R. China.
Chemphyschem. 2006 Mar 13;7(3):607-13. doi: 10.1002/cphc.200500389.
Affinity index (AT value), adsorption heat, X-ray diffraction (XRD), and 13C and 29Si magic-angle spinning (MAS) NMR, FTIR, and Raman spectroscopies were used to study the interaction of highly siliceous MFI-, FAU-, and FER-type zeolites with adsorbed methylamine (MA). Compared with the data for methanol, the much higher AT values and adsorption heats, and significant changes in XRD patterns, 29Si MAS NMR spectra, and FTIR spectra for the zeolites after adsorption of MA, revealed a strong hydrogen-bonding interaction between the perfect framework of the zeolites and the adsorbed MAs. This interaction results from the fact that the H atom of the amine group attacks the [Si-O] framework to form a Si-OHN bond, which leads to the appearance of Si-N bonds in the zeolites at 323 K. Therefore, the zeolite framework can be modified with MA under mild conditions. The highly siliceous MFI zeolite and the H-ZSM-5 zeolite with SiO2/Al2O3=31:1 were modified with MA and investigated by temperature-programmed desorption of CO2. The modified zeolites exhibited greatly enhanced basic properties in comparison with those of the raw materials. The influence of defects in the zeolite on the adsorption and the interaction with MA is discussed.
采用亲和指数（AT值）、吸附热、X射线衍射（XRD）、13C和29Si魔角旋转（MAS）核磁共振、傅里叶变换红外光谱（FTIR）以及拉曼光谱等方法，研究了高硅MFI型、FAU型和FER型沸石与吸附的甲胺（MA）之间的相互作用。与甲醇的数据相比，MA吸附后沸石的AT值和吸附热高得多，XRD图谱、29Si MAS NMR光谱和FTIR光谱也有显著变化，这表明沸石的完美骨架与吸附的MA之间存在强烈的氢键相互作用。这种相互作用源于胺基的H原子攻击[Si-O]骨架形成Si-OHN键，导致在323 K时沸石中出现Si-N键。因此，在温和条件下，MA可以对沸石骨架进行改性。用MA对高硅MFI沸石和SiO2/Al2O3 = 31:1的H-ZSM-5沸石进行改性，并通过程序升温脱附CO2进行研究。与原料相比，改性沸石的碱性显著增强。讨论了沸石中的缺陷对吸附以及与MA相互作用的影响。
