晶化后冷却方式诱导形成不同结构的微孔材料

• 作 者: 马延风 许雅群 李林杰 任元 李牛
• 机 构: 南开大学材料科学与工程学院,新催化材料科学研究所,天津300071;南开大学化学学院,高分子材料化学研究所,天津300071
• 出 处: 南开大学学报（自然科学版）
• 发表日期: 2021年6期
• 关键词: crystallization microporous materials cooling rate ethylenediamine-CoPO4 1 2-dia

乙二胺(EDA)导向的磷酸钴和1,2-二氨基丙烷(PDA)导向的磷酸锌水热晶化产生了一个有趣的结果,晶化产物受反应釜降温冷却速率支配.为了理解这种现象背后的原因和机制,这两个系统各自在不同温度下结晶1-6 d,然后分别采用快速冷却(10 rain)或缓慢冷却(3 h)路线.结果 表明,在一定的结晶时间范围内,缓慢的冷却会导致骨架转变.研究表明,这种转变在EDA-CoPO4体系中是低温优选的,缓冷过程使系统有一段时间在较低温度下进行转变.然与PDA-ZnPO4体系中转变则与大多数晶体的转变规律一致,更高温度有利于转变,SAPO-CHA分子筛合成体系中的进一步研究也得到了类似的结果,这个结果突显了EDA-磷酸钴系统结晶的特别之处.“,”An interesting result with the products of crystallization being dominated by the cooling rate has been raised in the crystallization of ethylenediamine (EDA)-directed cobalt phosphates and 1,2-diamino-propane (PDA)-directed zinc phosphates.To explore the reason and mechanism behind this phenomenon,these two systems were crystallized under different temperatures from 1 to 6 d followed by fast cooling (in 10 min) or slow cooling (in 3 h) route,respectively.The results showed that,within a certain range of crystallization time,slow cooling rate would result in a framework transformation.Further investigation indi-cates that this transformation is lower-temperature-preferable in EDA-CoPO4 system,and the slow cool-ing process give the system a period of time to carry out the transformation under lower temperature.However,in PDA-ZnPO4 system,a higher-temperature-preferable transformation has been found,and fur-ther study on SAPO-CHA presents a similar result,which is in consistent with general transformation conditions of most crystals,which protrudes the uniqueness of EDA-directed crystallization of cobalt phos-phates systems.