Kraft lignin depolymerisation by based catalysed degradation (BCD) - The effect of process parameters on conversion degree and structural features of BCD fractions
The objective of the study is the generation of oxy-aromatic compounds (monomer, oligomer) from Eucalyptus- Kraft-lignin via multi-stage processes. These processes (1st base catalysed degradation & 2nd separation of the organic phase from reactor water) have to be feasible in bio refineries & in new Pulp-mill bio refineries as a new technology module. The Eucalyptus-Kraft-lignin (Suzano Pulp & Paper) was used for catalyzed conversion into oxy aromatics. Subsequently, the effect of process parameters: catalyst & catalyst conc., mineral content, p: 250bars, 15min), T: 350°C)) was investigated. Liquid-liquid extraction of reactor water (pH=3) was performed with MIBK for isolation of the monomer rich phase. The BCD fractions (oils) & (tars) were characterized regarding their yields via carbon balance, & their composition. A characterization of the monomer composition was done (GC-MS/FID & EA (CHONS), 31P-NMR, 2D-NMR (HSQC), TGA). Types of monomers were summarized into groups (guaiacols (G), syringols (S), catechols (C )). Oligomer degradation products in the oil were characterized by Infusion MS Ion Trap & the composition of the oligomer phase by PyGC-MS, SEC, EA, 31P-NMR, 2D-NMR (HSQC) & TGA. On the one hand, depending on the botanical source & the lignin recovery process (Organosolv, Kraft etc.), useful lignins differ in their structure (inter unit linkages) & monomer composition, mineral & sulphur content, MW, MN. These substrate factors effecting the degradation process during the catalysed cleavage of aryl-aryl-ether & aryl-methyl-ether bonds. On the other hand, process factors e. g.: p, catalyst conc. & type of alkaline elements have a main effect on the cleavage processes, on the yield & composition of the monomer rich phase (oil), on the molecular characteristic (Mw, Mn, OH-number (aliphatic & phenolic -OH)) of the oligomer rich phase (tar) & on the carbon balance. To get an overview about the main & side effects in such complex situation, the study on the Kraft-lignin was done using DoE (Box-Behnken). A detailed evaluation regarding the main & side effects of process factors on the yield of oil & tar, on the concentration of (G), (S) & (C ) in the oil phase, on the carbon balance, on MW & MN of the tars as well on functional groups (OH-number, differentiated into aliphatic & phenolic), presence of inter unit linkages & methoxy groups will be given.
| Main Authors: | , , , , , , , , |
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| Format: | capítulo de libro biblioteca |
| Language: | English |
| Published: |
CSIC - Instituto de Recursos Naturales y Agrobiología de Sevilla (IRNAS)
2014-06-24
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| Subjects: | Lignin, Depolymerization, Based catalysed degradation, 2D NMR, Kraft, Eucalyptus, |
| Online Access: | http://hdl.handle.net/10261/98722 |
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