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Bulletin of the Korean Chemical Society (BKCS)

ISSN 0253-2964(Print)
ISSN 1229-5949(Online)
Volume 20, Number 2
BKCSDE 20(2)
February 20, 1999 

 
Title
Synthesis and Characterization of Zeolite L
Author
Yong Sig Ko, Wha Seung Ahn
Keywords
Abstract
Substantial reduction in synthesis time was achieved for zeolite L crystallization by attempting a hydrothermal synthesis at elevated temperature of 443K in a Na+/K+ mixed alkali system. Pure zeolite L could be obtained from a gel with the molar composition 5.4K2O-5.7Na2O-Al2O3-30SiO2-500H2O after 24h. Zeolite L could be obtained in high purity at the optimum Na2O/(K2O+Na2O) ratio of around 0.5, whilst zeolite W was formed when the Na2O/(K2O+Na2O) ratio was more than 0.66. The crystalline zeolite L samples obtained were characterized by means of elemental chemical analysis, XRD, SEM, FFi.r. spectroscopy, and particle size analyzer. In addition, two probe reaction studies were conducted. In toluene alkylation, H-L catalyst showed high catalytic activity at the beginning, but was deactivated quickly probably due to one-dimensional pore structure being blocked by the coke formed. High amounts of trimethylbenzene or diethylbenzene were observed due to the large 12-membered ring pore structure of zeolite L. Pt/NaKL catalyst prepared showed a high conversion of n-hexane and high selectivity to benzene in n-hexane aromatization reaction.
Page
173 - 178
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