MTT结构分子筛的合成及应用

SYNTHESIS AND APPLICATION OF MTT STRUCTURE ZEOLITES

考察了晶化温度、晶化时间及升温时间对合成MTT结构分子筛的影响;探讨了其水热稳定性差的原因,并寻找解决途径;对其催化性能进行了评价。结果表明,晶化温度在170℃左右较为合适;升温及晶化时间对最终产物也有很大的影响;杂晶的生成机理不同,ZSM-5是在成核阶段就与MTT分子筛伴生,而石英杂晶则是由MTT分子筛转晶或二次成核所致;磷改性能有效抑制分子筛的骨架脱铝;MTT结构分子筛用于催化裂化生产低碳烯烃的反应,具有很好的丙烯选择性。

The effects of crystallization temperature, crystallization time and heating time on the structure of MTT molecular sieve were investigated. The low hydrothermal stability of MTT was discussed to find its solution method, at the same time, catalytic performance of MTT was also evaluated. The results indicated that the suitable crystallization temperature was about 170℃, heating and crystallization times had great effect on the final product. Creation mechanism of impure crystal was different, ZSM-5 created with MTT at the nucleation period, while quartz phase was formed by the transition of MTT or secondary nucleation. Modification by P can effectively inhibit the dealuminum in the framework of molecular sieve. When the MTT molecular sieve was used as catalyst in catalytic cracking for low-carbon alkene production, high selectivity to propylene could be obtained.