皂石的合成、表征及其催化性能

Synthesis, Characterization and Catalytic Activity of Saponites and Their Pillared Analogues

用水热法合成了皂石,并用羟基铝低聚物与其交联制得AICLS。用XRD、^(27)Al和^(29)Si MASNMR及吡啶吸附量表征其晶相、结构和表面酸性。合成产物的结晶度很高。皂石中T—O—T片内四面体层上铝量可由合成条件控制,表明交联密度的柱间距与铝量有关。在异丙苯裂解反应中,AICLS的活性高于皂石,但活性衰减较慢;样品的催化裂化活性与探针分子可抵达的强酸中心数有关。

Saponite clays (S) were synthesized by hydrothermal mathod. The pillared saponite clays (Al-CLS) were prepared by intercalating the saponite with aluminum hydsoxy polymer [A113O4 (OH)24 · (H2O)12]7+. Saponite clays and their pillared clays were characterized with XRD, 27A1 and 2*Si MAS NMR and the amount of adsorped pyridine. The catalytic activity of saponites and their pillared anologues were evaluated for cumene cracking. The results show that the synthetic products were of good crystallinity and the aluminum amount in the tetrahedral layer of T-O-T sheet of saponite could be controlled by synthetic condition. The crosslinking density is correlative with aluminum amount in the tetrahedral layer. Compared with saponite, the activity for cumene cracking on the Al-CLS is higher but activity decay is lower. The catalytic activity of the sample is correlated with the number of strong acid sites on the surface where the probe molecule can arrive.