Catalytic wet-air oxidation of lignin in a three-phase reactor with aromatic aldehyde production

• Autor(a) principal: Sales,F.G.
• Data de Publicação: 2004
• Outros Autores: Abreu,C. A. M., Pereira,J. A. F. R.
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Brazilian Journal of Chemical Engineering
• Texto Completo: http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0104-66322004000200010
• topic: catalytic wet air-oxidation; lignin; vanillin; syringaldehyde p-hydroxybenzaldehyde; palladium catalyst; three-phase fluidized-bed reactor

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.