On the influence of Si:Al ratio and hierarchical porosity of FAU zeolites in solid acid catalysed esterification pretreatment of bio-oil
| Autor: | Caio C. S. Oliveira, Karen Wilson, Javier Pérez-Ramírez, Amin Osatiashtiani, Begoña Puértolas, Mark A. Isaacs, Jinesh C. Manayil, Chrysoula M. Michailof, Eleni Heracleous, Brunella Barbero, Adam F. Lee |
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| Rok vydání: | 2017 |
| Předmět: |
Inorganic chemistry
Bio-oil 02 engineering and technology engineering.material 010402 general chemistry 01 natural sciences Catalysis Acetic acid chemistry.chemical_compound Esterification Pyrolysis heterogeneous catalysis Adsorption Zeolite chemistry.chemical_classification Renewable Energy Sustainability and the Environment Faujasite 021001 nanoscience & nanotechnology 0104 chemical sciences Acid strength chemistry Benzyl alcohol engineering Methanol 0210 nano-technology Nuclear chemistry |
| Zdroj: | Biomass Conversion and Biorefinery, 7 (3) |
| ISSN: | 2190-6823 2190-6815 |
| DOI: | 10.1007/s13399-017-0254-x |
| Popis: | A family of faujasite (FAU) zeolites with different Si:Al ratio, and/or hierarchical porosity introduced via post-synthetic alkaline desilication treatment, have been evaluated as solid acid catalysts for esterification pretreatments of pyrolysis bio-oil components. Acetic acid esterification with aliphatic and aromatic alcohols including methanol, anisyl alcohol, benzyl alcohol, p-cresol and n-butanol was first selected as a model reaction to identify the optimum zeolite properties. Materials were fully characterised using N2 porosimetry, ICP, XRD, XPS, FT-IR, pyridine adsorption, NH3 TPD, In-situ ATR and inverse gas chromatography (IGC). IGC demonstrates that the surface polarity and hence hydrophobicity of FAU decreases with increased Si:Al ratio. Despite possessing a higher acid site loading and acetic acid adsorption capacity, high Al-content FAU possess weaker acidity than more siliceous catalysts. Esterification activity increases with acid strength and decreasing surface polarity following the order FAU30>FAU6>FAU2.6. The introduction of mesoporosity through synthesis of a hierarchical HFAU30 material further enhances esterification activity through improved acid site accessibility and hydrophobicity. Methanol was the most reactive alcohol for esterification, and evaluated with HFAU30 for the pretreatment of a real pyrolysis bio-oil, reducing the acid content by 76% under mild conditions. |
| Databáze: | OpenAIRE |
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