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Effects of synthesis conditions on the yields and properties of HZSM‐5
Author(s) -
Wang Yuan,
Fan Subing,
Zhang Jianli,
Zhao TianSheng
Publication year - 2015
Publication title -
crystal research and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.377
H-Index - 64
eISSN - 1521-4079
pISSN - 0232-1300
DOI - 10.1002/crat.201400481
Subject(s) - chemistry , materials science , chemical engineering , engineering
In the SiO 2 ‐Al 2 O 3 ‐TPAOH‐NH 4 OH system through a two‐step procedure, the effects of synthesis parameters on the yields and properties of HZSM‐5 were studied. As the feeding n(SiO 2 )/n(Al 2 O 3 ) ratio increased, the yields of synthesized samples were between 11% and 14% while the crystallinity tended to decrease at the ratio > 300. At the ratio of 150, the yield was 13.7% and the ratio of actual yield to theoretical yield was 93%. The sample shaped ellipse‐like particles of 3 × 10 −6 m. At the n(NH 3 )/n(SiO 2 ) ratio of 1.5, the yield was 13.1% and the sample showed regular ellipse‐like particles of 2 × 10 −6 m. Too high dosage of NH 4 OH lowered the yield and the crystallinity. The addition of seed crystal favored the HZSM‐5 synthesis in high crystallinity. At the addition amount of 4%, the yield reached 13.9% and the sample shaped in spherical particles of 0.5 × 10 −6 m. Synthesized HZSM‐5 with a surface area of 455 m 2 ·g −1 and intrinsic acidity showed highly catalytic activity toward the methanol conversion to olefins reaction.