二甘醇
三甘醇
乙二醇
溶剂
结晶
奥斯特瓦尔德成熟
化学
化学工程
Crystal(编程语言)
相(物质)
ZSM-5型
结晶学
材料科学
沸石
有机化学
催化作用
工程类
计算机科学
程序设计语言
作者
Sinthuran Jegatheeswaran,Chin‐Min Cheng,Chil‐Hung Cheng
标识
DOI:10.1016/j.micromeso.2014.09.008
摘要
This work systematically studies on adding alcohols to alter the crystal growth behavior of ZSM-12, using 1-propanol (1P), 2-propanol (2P), ethylene glycol (EG), 1,3-propanediol (PD), 1,6-hexanediol (HD), diethylene glycol (DEG), triethylene glycol (TEG), and tetraethylene glycol (TTEG) as co-solvents. The effects of co-solvent content, temperature, and excess mineralizer content were studied as well. Except 2P, all other co-solvents are observed to tune the crystal morphology into a discrete round-shape. Except DEG and TTEG, all other co-solvents promote the crystallization rate of MTW phase, verified by larger zeolite crystal size in SEM images. The observation is corroborated with the formation of cristobalite, possibly via Ostwald ripening mechanism. The finding enlightens us using a lower synthesis temperature to attain high purity MTW phase, with an adequate amount of co-solvents. It is noteworthy that using HD as co-solvent facilitate the anisotropic growth of MTW crystals along the b-axis (2θ of 8.5°), possibly due to the effect of co-solvent’s hydrophobicity as well as the backbone length. The blue shift of symmetric and asymmetric Si-O vibration modes in FTIR spectra implies that TEG and HD are incorporated within the ZSM-12 pore structure. This work provides potential synthetic route to form anisotropic ZSM-12 membranes with preferred orientation.
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