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ID 46487
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title alternative
Effects of Composition of Synthesis Mixture on Silicalite Crystal Growth
creator
Sugawara, Seiho
Takeda, Kiyoshi
Kawakami, Yusuke
Iwasaki, Akira
NDC
Chemistry
abstract
水熱合成条件下でのゼオライト結晶の成長過程を直接観察するために新しいタイプのその場観察装置を開発し,これを用いてシリカライトの結晶成長速度及び結晶形態に及ぼす結晶化温度及び原料溶液組成の影響を詳細に検討した.孤立した特定の結晶の大きさの経時変化の傾きから求めた長さ及び幅方向の成長速度は結晶化時間によらず一定であり,結晶化温度が高いほど大きくなることがわかった.また,結晶形態は結晶化温度に依存し,高温ほど細長くなることがわかった.次に,出発原料溶液組成を以下のように変えて結晶成長速度に及ぼす溶液組成の影響を調べた.
(1) xTPA2O-0.05Na2O-SiO2 - 300H2O ( x = 0.012 ~ 0.1)
(2)0.05TPA2O -yNa2O- SiO2 - 300H2O ( y=0.025 ~ 0.2)
(3)0.05TPA2O -0.05Na2O - zSiO2- 300H2O ( z = 0.5 ~ 2)
(4)0.05TPA2O -0.05Na2O - SiO2 - wH2O ( w= 100 ~ 1000)
得られた結晶の大きさの経時変化から求めた各組成における長さ方向の成長速度Rlおよび幅方向の成長速度Rwから,次の相関式が得られた.
Rl∝ (TPA+)0.389(OH-)0.518(SiO2) -0.196(6H2O) -0.745
Rw∝(TPA+)0.675(OH-)1.05(SiO2) -0.226(H2O) -1.12
Rl/Rw∝ (TPA+)-0.286(OH-) -0.528(SiO2)0.0296( H2O)0.369
abstract
To clarify the crystal growth process of zeolite under hydrothermal synthesis condition, a new type apparatus for the in-situ observation was developed. In the present work, the growth behavior of silicalite crystals from clear aqueous solutions was studied using the apparatus. Effects of the crystallization tern perature and the composition of synthesis mixture on the growth rate and the morphology of specified crystal were investigated systematically. The crystal length growth rate (Rl) and width growth rate (Rw) increased significantly with an increase in the temperature. The morphology was also affected by the temperature.
Next, effects of the composition of synthesis mixture on the crystal growth rate and the morphology was investigated using the following synthesis mixtures.
(1) xTPA2O-0.05Na2O-SiO2 - 300H2O ( x = 0.012 - 0.1)
(2)0.05TPA2O -yNa2O- SiO2 - 300H2O ( y=0.025 - 0.2)
(3)0.05TPA2O -0.05Na2O - zSiO2- 300H2O ( z = 0.5 - 2)
(4)0.05TPA2O -0.05Na2O - SiO2 - wH2O ( w= 100 - 1000)
The growth rate and the crystal morphology were affected markedly by changing the composition of synthesis mixture. The following relationships were obtained;
Rl∝ (TPA+)0.389(OH-)0.518(SiO2) -0.196(H2O) -0.745
Rw∝ (TPA+)0.675(OH-)1.05(SiO2) -0.226(H2O) -1.12
Rl/Rw∝ (TPA+)-0.286(OH-) -0.528(SiO2)0.0296( H2O)0.369
journal title
Journal of the Chemical Society of Japan : chemistry and industrial chemistry
volume
Volume 1995
issue
Issue 8
start page
615
end page
621
date of issued
1995-08-10
publisher
日本化学会
issn
0369-4577
ncid
publisher doi
language
jpn
nii type
Journal Article
HU type
Journal Articles
DCMI type
text
format
application/pdf
text version
publisher
rights
Copyright (c) 1995 The Chemical Society of Japan
relation url
department
Graduate School of Engineering