1-ブタノールを結晶化調整剤とするZSM-5型ゼオライトの合成とその性質 <論文>

Arazaki Shuichi

Kasuno Takekazu

Sano Tsuneji

Kawakami Yusuke

Shoji Hiroshi

日本化学会誌 : 化学と工業化学

Journal of the Chemical Society of Japan : chemistry and industrial chemistry

テトラプロピルアンモニウムプロミド(TPABr)のように有機カチオンとしてではなく中性分子として作用し,かつ比較的分子構造が簡単な脂肪族アルコールを結晶化調整剤としてZSM-5型ゼオライト合成を行い,TPABrを用いて合成したZSM-5ゼオライトとその物性を比較することにより,結晶化調整剤としての脂肪族アルコールの役割について検討した.得られたゼオライトの結晶化度は用いたアルコールの種類に依存し,炭素数4～6の直鎖アルコールとりわけ1-ブタノールがZSM-5型ゼオライトの合成に有効であること,及びZSM-5型ゼオライト結晶を純相として得るためには少なくとも1-butano1/SiO2比は1以上にする必要があることがわかった.また,合成できるゼオライトのSiO2/Al2O3比の範囲は20～100とTPABrを用いた場合に比べ狭かった.なお,熱分析および13C-MASNMRの測定結果より,合成直後のゼオライト細孔内には1-ブタノールが存在していることが明らかとなった.さらに,FT-IRスペクトル測定及び水の吸着実験から,1-ブタノールを用いて合成したゼオライトは格子欠陥の少ないことが示唆された.

Synthesis of ZSM-5 type zeolites has been carried out using various structure-directing reagents such as amine, diamine, amino alcohol, hydrocarbon and alcohol as well as tetrapropylammonium bromide (TPABr). The role of the directing reagent and the properties of zeolites synthesized, however, have not been sufficiently clarified. In this paper, synthesis of ZSM-5 type zeolites was conducted using various aliphatic alcohol and their properties were investigated in detail. It was found that the highly crystalline ZSM-5 type zeolites were synthesized using 1-butanol and 1-hexanol (Table 1). In the case of 1-butanol, the crystallinity of zeolite was increased with an increase in 1-butanol/SiO2 ratio of the starting synthesis mixture and the highest crystallinity was obtained for over 1 of 1-butanol/SiO2 ratio (Table 2). The production of cristobalite as by-product was considerably depressed by addition of 1-butanol. These results indicate that 1-butanol acts as the structure-directing reagent. The SiO2/Al2O3 ratios of zeolites synthesized using 1-butanol were lower than those of the starting synthesis mixtures. The region of SiO2/Al2O3 ratio (30-150) was much smaller than that of zeolites with TPABr (Table 3). The Al-free zeolite, silicalite, could not be prepared using 1-butanol. Figure 4shows the FT-IR spectra of hydroxyl groups of HZSM-5 zeolites synthesized using (A) 1-butanol and (B) TPABr. The spectra of HZSM-5 from TPABr were characterized by two well-defined absorptions at 3605 and 3740 cm-1. The former band has been assigned to stretching vibration of an acidic bridged OH of Si (OH) Al, while the latter one to terminal Si-OH. On the other hand, two peaks at 3605 and 3740 cm-1 were also observed in the spectra of zeolites using 1-butanol. However, the intensity of the peak at 3740 cm-1 was very weak. The drastic decrease in the intensity of the peak at 3740 cm-1 may suggest the concentration of the internal Si-OH groups (structure defects) is relatively small. This is also confirmed by the fact that the amount of water adsorbed on zeolite synthesized with 1-butanol was smaller than that on zeolite with TPABr.

Chemistry [ 430 ]

jpn

日本化学会

Copyright (c) 1995 The Chemical Society of Japan

[ISSN] 0369-4577

[NCID] AN00186595

[DOI] 10.1246/nikkashi.1995.606

[DOI] https://doi.org/10.1246/nikkashi.1995.606