摘要
以不同链长的有机胺为模板,选用不同的铝源,采用水热法合成AHT型分子筛。考察铝源、原料摩尔比和有机模板剂对AHT型磷酸铝分子筛(AlPO_(4)-H_(2))合成的影响,并利用XRD、SEM、BET、TG/DTG等技术对合成的AHT构型磷酸铝分子筛进行表征。结果表明,在所测试的4种铝源中,只有以拟薄水铝石为铝源时才能获得AHT型分子筛;反应混合物中水的含量对AHT型磷酸铝分子筛的合成具有显著的影响,当n(H_(2)O)/n(Al_(2)O_(3))大于或小于20时,均有杂相生成;在优化的条件下,以烷基链长度大于4的有机胺为模板剂,均能获得纯相的AHT型磷酸铝分子筛。当有机胺烷基链长度小于或等于4时,有机胺的最大伸展长度达不到AHT型磷酸铝分子筛的晶胞参数c值,无法合成纯相AHT型磷酸铝分子筛。合成的AHT型磷酸铝分子筛形貌为针状或棒状,结构骨架中磷铝摩尔比为1,是一种典型的磷酸铝分子筛。该分子筛具有良好的酸碱稳定性,但高温容易导致其结构转变。
AHT aluminophosphate molecular sieves(AlPO_(4)-H2)were synthesized by hydrothermal method using different chain-length organic amines as templates and different aluminum sources.The effects of aluminum sources,substrate molar ratio,and organic template on the synthesis of AHT aluminophosphate molecular sieves were investigated.Multiple analytical techniques,including XRD,SEM,BET,and TG/DTG,were employed to characterize the AlPO4-H2.The results showed that only pseudo-boehmite can be used to synthesize AlPO_(4)-H2 among the four tested aluminum sources.The water content in the reaction mixture has a remarkable impact.When n(H2O)/n(Al2O3)was over or less than 20,impurities were formed.When the length of the alkyl chain of the organic amines was larger than 4,pure AlPO4-H2 can be obtained under optimized conditions.While the alkyl chain length of organic amine was smaller than or equal to 4,pure AlPO4-H2 cannot be obtained,because the stretching extends of these amines are smaller than the value of crystal cell parameter c.The morphology of the synthesized AlPO4-H2 was needle-like or rod-like,with a n(Al)/n(P)of 1 in its structural skeleton.This molecular sieve has good chemical stability although it is unstable at high temperature.
作者
王晓天
罗海燕
徐俊波
杨超
刘会洲
李英波
WANG Xiaotian;LUO Haiyan;XU Junbo;YANG Chao;LIU Huizhou;LI Yingbo(CAS Key Laboratory of Green Process and Engineering,Institute of Process Engineering,Chinese Academy of Sciences,Beijing 100190,China;College of Chemical Engineering,University of Chinese Academy of Sciences,Beijing 100049,China;Yabang Institute of Green Process and Advanced Materials,Nanjing 210047,Jiangsu,China)
出处
《化工进展》
EI
CAS
CSCD
北大核心
2021年第11期6219-6227,共9页
Chemical Industry and Engineering Progress
基金
国家重点研发计划重点专项(2016YFB0301702)
中国科学院科技服务网络计划(STS计划)区域重点项目(KFJ-STS-QYZD-2021-14-002)。
关键词
分子筛
有机胺
AHT
磷酸铝
合成
molecular sieves
organic amine
AHT
aluminophosphate
synthesis
