TY - JOUR
T1 - Novel synthesis of aluminum hydroxyfluorides AlFx(OH)3-x and application in E-1-chloro-3,3,3-trifluoropropene isomerization
AU - Feng, Shiwei
AU - Zhang, Chengping
AU - Quan, Hengdao
N1 - Publisher Copyright:
© 2023 Elsevier Ltd
PY - 2023/8
Y1 - 2023/8
N2 - A facile, safe, and environmentally friendly preparation method is described for the synthesis of AlFx(OH)3-x by the activation of γ-Al2O3 using HCFO-1233zd(E) under various temperatures. Comprehensive characterization techniques including XRD, XPS, N2 sorption, SEM, TEM, 27Al MAS NMR, FTIR, and py-IR were employed, revealing that at lower temperatures such as 275 °C and 300 °C, the synthesis yielded AlF(OH)2, while at higher temperatures like 350 °C and 375 °C, pyrochlore AlF1.5(OH)1.5 and metastable hexagonal tungsten bronze-type (HTB) β-AlF3 were formed, with α-AlF3 detected at 325 °C. Notably, a significant quantity of AlF(OH)2 can be obtained at 325 °C within a specific time frame. This amorphous phase exhibits weak Lewis acid sites and a lower acid density, rendering it significantly more effective in the isomerization of HCFO-1233zd(E) compared to strong Lewis acid catalysts such as AlF1.5(OH)1.5 and β-AlF3, which could promote coke formation, leading to catalyst deactivation. Moreover, due to its limited further fluorination at 290 °C, the optimal catalyst exhibits prolonged lifespan and high efficiency in HCFO-1233zd(E) isomerization.
AB - A facile, safe, and environmentally friendly preparation method is described for the synthesis of AlFx(OH)3-x by the activation of γ-Al2O3 using HCFO-1233zd(E) under various temperatures. Comprehensive characterization techniques including XRD, XPS, N2 sorption, SEM, TEM, 27Al MAS NMR, FTIR, and py-IR were employed, revealing that at lower temperatures such as 275 °C and 300 °C, the synthesis yielded AlF(OH)2, while at higher temperatures like 350 °C and 375 °C, pyrochlore AlF1.5(OH)1.5 and metastable hexagonal tungsten bronze-type (HTB) β-AlF3 were formed, with α-AlF3 detected at 325 °C. Notably, a significant quantity of AlF(OH)2 can be obtained at 325 °C within a specific time frame. This amorphous phase exhibits weak Lewis acid sites and a lower acid density, rendering it significantly more effective in the isomerization of HCFO-1233zd(E) compared to strong Lewis acid catalysts such as AlF1.5(OH)1.5 and β-AlF3, which could promote coke formation, leading to catalyst deactivation. Moreover, due to its limited further fluorination at 290 °C, the optimal catalyst exhibits prolonged lifespan and high efficiency in HCFO-1233zd(E) isomerization.
KW - Aluminum hydroxyfluoride
KW - Brønsted acid sites
KW - E-1-chloro-3,3,3-fluoropropene
KW - Lewis acid sites
KW - Z-1-chloro-3,3,3-fluoropropene
UR - http://www.scopus.com/inward/record.url?scp=85166297242&partnerID=8YFLogxK
U2 - 10.1016/j.mtchem.2023.101652
DO - 10.1016/j.mtchem.2023.101652
M3 - Article
AN - SCOPUS:85166297242
SN - 2468-5194
VL - 32
JO - Materials Today Chemistry
JF - Materials Today Chemistry
M1 - 101652
ER -