【摘要】 考察了膨胀剂的用量、合成体系的pH值和MCM-22(P)的硅/铝比对合成ITQ-2分子筛的影响.结果表明,同时降低膨胀剂十六烷基三甲基溴化铵和四丙基氢氧化铵的用量,在pH=11.5时4h即可完成对MCM-22(P)的插层膨胀;pH值降低时,可减小由于脱硅对ITQ-2分子筛硅/铝比下降的影响,并且使产物收率大幅度提高.同时,pH值降低使后续的超声剥离更加容易,且可避免生成MCM-41介孔分子筛杂相.MCM-22(P)的硅/铝比越大,层表面的电荷密度越低,带负电荷的层板和阳离子插层剂之间的静电引力和分子间作用力也就越小,致使插层膨胀和随后的超声剥离越容易.更多还原

【Abstract】 The effects of the amount of swelling agents (CTMABr and TPAOH),the pH value of the synthesis system,and the SiO2/Al2O3 ratio of MCM-22(P) on the synthesis of ITQ-2 zeolite were investigated. The results showed that well-swollen MCM-22(P) could be obtained within only 4 h at pH=11.5 by decreasing the amount of swelling agents. With the pH value decreasing,the desiliconization of MCM-22(P) greatly decreased,the yield of ITQ-2 zeolite significantly increased,and the ultrasonic exfoliation process became more accessible. The MCM-41 mesophase could be avoided when the exfoliation process was performed at lower pH value. The higher the SiO2/Al2O3 ratio of the MCM-22(P),the lower the charge density on the sheet surface,the weaker the electrostatic attractive force and the intermolecular force between the interlayer cation and negatively charged sheets,which made the intercalation swelling and succedent ultrasonic exfoliation easier.更多还原