Clays and Clay Minerals, Vol. 58, No. 4, 475–485, 2010.
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Authors
Xi, Yuanzhou
Davis, Robert J.
Issue Date
2010
Type
Article
Language
Keywords
Periodicals , Geology , Biodiesel , Catalyst , DTG , FTIR , Glycerol , Hydrotalcite , TGA , Transesterification , Tributyrin , XRD
Alternative Title
Glycerol-intercalated Mg-al Hydrotalcite As A Potential Solid Base Catalyst For Transesterification
Abstract
Glycerol is a byproduct of biodiesel synthesis by transesterification of triglycerides with shortchain alcohols in the presence of solid base catalysts. Because hydrotalcite is a potentially useful basic catalyst for the transesterification reaction, the interaction of glycerol with hydrotalcite is the focus of this work. Glycerol was intercalated into Mg-Al hydrotalcite with a Mg/Al molar ratio of 4 under elevated temperatures of 443-503 K in the absence and presence of NaOH. The resulting materials were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, thermogravimetric analysis, and N2 adsorption. The amount of glycerol incorporated into hydrotalcite increased with increasing temperature of intercalation. However, the brucite-like sheets of hydrotalcite partially decomposed during the intercalation process at the highest temperature. The presence of NaOH stabilized the hydrotalcite layers against decomposition under high temperature (503 K). The intercalated materials exposed large surface areas ranging from 142 to 663 m2 g-1, depending on the preparation conditions. The glycerolintercalated hydrotalcites were less catalytically active than hydrotalcite with OH- counterions for the transesterification of tributyrin with methanol. The lower reactivity of glycerol-intercalated hydrotalcite was probably the result of a strong interaction between the intercalated glycerolate (HOCH2-CHOHCH2O-) and the partially decomposed brucite-like sheets.
Description
gsccm58403-dav.pdf -- 349KB
Citation
Clays and Clay Minerals, Vol. 58, No. 4, 475–485, 2010.
Publisher
The Clay Minerals Society
License
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