关键词: 微波水热合成;水热条件;SAPO-11晶体;二乙胺;结构性质

Abstract: Effect of various reaction temperature and time on crystal structure properties of SAPO-11 synthesized from diethylamine template via microwave-assisted hydrothermal route was investigated in this paper. These obtained products were characterized by XRD, FT-IR, SEM, BET and NH3-TPD techniques to investigate their crystalline phase, skeletal structure, morphology, pore structure and surface acidity. The results indicate that different hydrothermal conditions pose significant impact on the structure properties of the synthesized products. Only SiO2 phase but no SAPO-11 crystalline phase existed in the product synthesized when the reaction temperature below 180 ℃, and the SAPO-11 with rather small specific surface area and inhomogeneity in crystal size was also obtained when the reaction temperature higher than 200 ℃. A small amount of AlPO4-5 and CFSAPO-1 ( C ) miscellaneous crystal phases are derived from SAPO-11 crystal when the reaction time over 1 h. The product with pure SAPO-11 phase and spherical crystalline grains was eventually and successfully synthesized at 200℃ for 1 h via microwave-assisted hydrothermal route, and the SAPO-11 possessed distinct physicochemical properties with the weak acid on the surface, high specific surface area of 199. 4 m2·g-1, pore volume of 0. 15 cm3 ·g-1 and average pore diameter of 2. 92 nm.

Key words: Effect of various reaction temperature and time on crystal structure properties of SAPO-11 synthesized from diethylamine template via microwave-assisted hydrothermal route was investigated in this paper. These obtained products were characterized by XRD, FT-IR, SEM, BET and NH3-TPD techniques to investigate their crystalline phase, skeletal structure, morphology, pore structure and surface acidity. The results indicate that different hydrothermal conditions pose significant impact on the structure properties of the synthesized products. Only SiO2 phase but no SAPO-11 crystalline phase existed in the product synthesized when the reaction temperature below 180 ℃, and the SAPO-11 with rather small specific surface area and inhomogeneity in crystal size was also obtained when the reaction temperature higher than 200 ℃. A small amount of AlPO4-5 and CFSAPO-1 ( C ) miscellaneous crystal phases are derived from SAPO-11 crystal when the reaction time over 1 h. The product with pure SAPO-11 phase and spherical crystalline grains was eventually and successfully synthesized at 200℃ for 1 h via microwave-assisted hydrothermal route, and the SAPO-11 possessed distinct physicochemical properties with the weak acid on the surface, high specific surface area of 199. 4 m2·g-1, pore volume of 0. 15 cm3 ·g-1 and average pore diameter of 2. 92 nm.