Bamboo Leaf Ash As A Green And Sustainable Source Of Amorphous Silica For The Synthesis Of Zeolite Catalyst Materials For Cyanoethylation Of Alcohols
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Date
2017-07
Authors
Chow, Jack Hao
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Publisher
Universiti Sains Malaysia
Abstract
The aim of this project was to study the potential use of bamboo leaf ash (BLA) for the synthesis of LTA- and X-type zeolites which were the catalysts for the cyanoethylation of alcohols reaction. The amorphous BLA with high silica content (99.37% SiO2) was first prepared via acid treatment prior to combustion at 600 °C. LTA-type zeolite (NaA) was synthesized from BLA under hydrothermal condition. The effect of synthesis (heating temperature, time and chemical composition) were studied as they had significant effects on the average size, size distribution, morphology and purity of the solid products. In addition, the catalyst reusability of zeolite NaA was also tested. Zeolite NaA is found to be reactive in cyanoethylation reaction (150 C, 12 h) under autogenous pressure, giving 85.4% conversion of acrylonitrile to 3-methoxy-propionitrile. X-type zeolites (FAU topology) with different alkali metal cations (Li+, K+, Cs+ and Ca2+) were prepared via ion exchange where BLA was used as the silica source. As expected, zeolite CsX with the strongest basicity showed the best catalytic performance in the cyanoethylation of alcohols. The results indicated that the surface basicity of zeolite X framework gradually increases in the order of LiX < NaX < CaX < KX < CsX. Among the catalysts prepared, CsX with the most basic feature gives the best catalytic performance (97.0% conversion) in the cyanoethylation reaction study (9 h, 150 °C, autogenous pressure) whereas moisture sensitive CaX (28.2%) shows the poorest performance under the same reaction condition.
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Keywords
Bamboo leaf ash as a green and sustainable source , the synthesis of zeolite catalyst materials