Highly selective transformation of poly[(R)-3-hydroxybutyric acid] into trans-crotonic acid by catalytic thermal degradation.
Highly selective transformation of poly[(R)-3-hydroxybutyric acid] (PHB) into trans-crotonic acid was achieved by thermal degradation using Mg compounds: MgO and Mg(OH)2 as catalysts. Through catalytic action, not only the temperature and Ea value of degradation were lowered by 40–50 °C and 11–14 kJ...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English English |
| Published: |
Elsevier
2010
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| Online Access: | http://psasir.upm.edu.my/id/eprint/15012/ http://psasir.upm.edu.my/id/eprint/15012/1/Highly%20selective%20transformation%20of%20poly.pdf |
| Summary: | Highly selective transformation of poly[(R)-3-hydroxybutyric acid] (PHB) into trans-crotonic acid was achieved by thermal degradation using Mg compounds: MgO and Mg(OH)2 as catalysts. Through catalytic action, not only the temperature and Ea value of degradation were lowered by 40–50 °C and 11–14 kJ mol−1, respectively, but also significant changes in the selectivity of pyrolyzates were observed. Notably, Mg(OH)2 showed nearly complete selectivity (∼100%) to trans-crotonic acid. Kinetic analysis of TG profiles revealed that the catalytic thermal degradation of PHB was initiated by some random degradation reactions, followed by the unzipping β-elimination from crotonate chain-ends as a main process. It was suggested that the Mg catalysts promote the totality of the β-elimination reactions by acting throughout the beginning and main processes, resulting in a lowering in the degradation temperature and the completely selective transformation of PHB. |
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