Catalytic wet-air oxidation of lignin in a three-phase reactor with aromatic aldehyde production
Brazilian Journal of Chemical Engineering. 2004;21(2):211-218
Journal Title: Brazilian Journal of Chemical Engineering
ISSN: 0104-6632 (Print); 1678-4383 (Online)
Publisher: Brazilian Society of Chemical Engineering
LCC Subject Category: Technology: Chemical technology: Chemical engineering
Country of publisher: Brazil
Language of fulltext: English
Full-text formats available: PDF, HTML, XML
Abreu C. A. M.
Pereira J. A. F. R.
Abstract | Full Text
In the present work a process of catalytic wet air oxidation of lignin obtained from sugar-cane bagasse is developed with the objective of producing vanillin, syringaldehyde and p-hydroxybenzaldehyde in a continuous regime. Palladium supported on g-alumina was used as the catalyst. The reactions in the lignin degradation and aldehyde production were described by a kinetic model as a system of complex parallel and series reactions, in which pseudo-first-order steps are found. For the purpose of producing aromatic aldehydes in continuous regime, a three-phase fluidized reactor was built, and it was operated using atmospheric air as the oxidizer. The best yield in aromatic aldehydes was of 12%. The experimental results were compatible with those values obtained by the pseudo-heterogeneous axial dispersion model (PHADM) applied to the liquid phase.