Alkali-free zn–al layered double hydroxide catalysts for triglyceride transesterification
Zn–Al layered double hydroxides (LDHs) of general formula Al3+ x(OH)2]x+(CO3Zn–Al2−)x/2·yH2O are promising solid base catalysts for the transesterification of lipids to biofuels. However, conventional synthetic routes employ alkali ydroxide/carbonate precipitants which may contaminate the final LDH...
Main Authors: | , , , , , |
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Format: | Article |
Language: | English |
Published: |
MDPI
2018
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Subjects: | |
Online Access: | View Fulltext in Publisher View in Scopus |
Summary: | Zn–Al layered double hydroxides (LDHs) of general formula Al3+ x(OH)2]x+(CO3Zn–Al2−)x/2·yH2O are promising solid base catalysts for the transesterification of lipids to biofuels. However, conventional synthetic routes employ alkali ydroxide/carbonate precipitants which may contaminate the final LDH catalyst and biofuel. The use of (NH3)2CO3 and NH3OH as precipitants affords alkali-free Zn–Al-LDHs spanning a wide composition range. The hydrothermal reconstruction of calcined Zn–Al-LDHs offers superior solid basicity and catalytic activity for the transesterification of C4–C18 triglycerides with methanol,compared with cold liquid phase or vapour phase reconstruction. Hydrothermally activated Zn3.3–Al-LDH was stable towards leaching during transesterification. © 2018 by the authors. Licensee MDPI, Basel, Switzerland. |
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ISBN: | 20734344 (ISSN) |
DOI: | 10.3390/catal8120667 |