Yang D.-X.,Shanghai Research Institute of Chemical Industry |
Yang D.-X.,Shanghai Luqiang New Materials Co. |
Wang P.-F.,Shanghai Research Institute of Chemical Industry |
Wang P.-F.,Shanghai Luqiang New Materials Co. |
And 8 more authors.
Gaodeng Xuexiao Huaxue Xuebao/Chemical Journal of Chinese Universities | Year: 2011
Nano-scaled SAPO-34 molecualr sieves with size in the range of 200-300 nm were synthesized by a two-step crystallization process, with pseudoboehmite, colloidal silica and H3PO4 as sources of aluminum, silicon and phosphorous and TEAOH as template. The prepared SAPO-34 zeolites was characterized by XRD, SEM, NH3-TPD, XRF, BET, 29Si, 27Al, 31P MAS NMR. And the catalytic performance of the SAPO-34 on the methanol-to-olefins(MTO) reactions was carried out on a fixed bed. The results show that the particle size of the SAPO-34 could be effectively modulated by the crystallization temperature of the two-step crystallization process. In particular, when the first and second crystallization were conducted at 130 and 180°C, cubic SAPO-34 with size in the range of 200-300 nm could be successfully synthesized. Compared with the micro-scaled SAPO-34 prepared by the traditional hydrothermal process, the nano-scaled SAPO-34 crystals synthesized show better performance in the MTO reaction and the selectivity of C2 =-C4 = and the lifetime for one-turn could attained about 92% and 10 h, respectively.