关键词: 含硼CF-2, 沸石, 转变过程, 多孔玻璃粉, ¹³CMASNMR, TG-DTG

The state changes of methylamine molecules in synthesis process of boron-containing CF-2 zeolite transformed from porous glass granules in a vapor phase of methylamine and water were studied using ¹³C MAS NMR and TG-DTG techniques. The results show that the methylamine molecules go through three states during the entire process of reaction. At the early stage of reaction, methylamine molecules weakly interact with the hydroxyls on the surfaces of porous glass. With the progress of reaction, part of them change to strongly interacting ones, resulting in co-existence of weakly and strongly interacting methylamine molecules. Then the strongly interacting methylamine molecules together with Si-OH, Al-OH, B-OH form nuclei, which grow up to form CF-2 zeolite crystals. The methylamine molecules gradually enter into the zeolite channels. At this stage, there are three kinds of methylamine, i.e., weakly and strongly interacting ones in porous glass, and molecules in zeolite channels. With further reaction, the weakly and strongly interacting methylamine molecules successively disappear. Finally, there are only free and protonated molecules located in the channels of CF-2 zeolite. SEM images support the transformation process from porous glass granules to boron-containing CF-2 zeolite in morphology.

Key words: boron-containing CF-2, zeolite, transformation process, porous glass granule, ¹³C MAS NMR, TG2DTG