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考察了水热条件下HZSM-5沸石骨架铝的迁出,气-固或液-固反应条件下外界铝进入骨架的影响因素及表面性质的变化。发现在相同的条件下,随ZSM-5沸石硅铝比的增加,铝迁入骨架的比率增大;经水热处理后较相同数量级硅铝比的未经处理的沸石的铝迁入骨架速率快,结合骨架铝迁移的机理对此现象进行了讨论。在400℃气-固反应时,进入沸石骨架的铝量达400—600℃总量的75—80％,和在400℃水热处理时骨架铝的迁脱量相当(80％),这部分铝主要对应于强酸中心位,说明沸石骨架中对应于酸中心较强而稳定性较弱的铝易迁出也易迁入,表明酸性中心是可逆的。
The effects of aluminum migration on the framework of HZSM-5 zeolite framework under hydrothermal conditions, and the influence of external aluminum entering the framework under gas-solid or liquid-solid reaction conditions and the changes of surface properties were investigated. Under the same conditions, the ratio of aluminum migrating into the framework increased with the increase of the Si / Al ratio of ZSM-5 zeolite. The untreated zeolite with the same order of Si / Al ratio after hydrothermal treatment migrated into the framework faster This phenomenon is discussed in combination with the mechanism of skeleton aluminum migration. At 400 ℃ gas-solid reaction, the amount of aluminum entering the framework of the zeolite reached 75-80% of the total amount of 400-600 ℃, and the amount of aluminum migration was comparable (80%) when hydrothermally treated at 400 ℃. This part of aluminum Mainly corresponds to the strong acid center, indicating that the zeolite framework corresponding to the strong acid center and the weak stability of the aluminum easy to move out also easy to move in, indicating that the acidic center is reversible.