Produção Nacional
Revisado por pares
Kraft Lignin-Based Polyols by Microwave: Optimizing Reaction Conditions
2017; Taylor & Francis; Volume: 37; Issue: 5 Linguagem: Inglês
10.1080/02773813.2017.1303513
ISSN1532-2319
AutoresSilvia Helena Fuentes da Silva, Patrícia Soares Bilhalva dos Santos, Daniela Thomas da Silva, Rodrigo Briones, Darci Alberto Gatto, Jalel Labidi,
Tópico(s)Enzyme-mediated dye degradation
ResumoMicrowave liquefaction of precipitated Kraft lignin was carried out in polyethylene glycol (PEG) and glycerol (G) mixed with or without H2SO4 as catalyst. The influences of some independent variables on the yield and hydroxyl index were discussed. The viscosity, molecular distribution (GPC), and the types of volatiles measured by gas chromatography–Mass spectrometry (GC-MS) of all the liquefied products were determined. Response surface methodology (RSM) was used to optimize liquefaction conditions. Based on the results, lignin/solvents (wt%), catalyst/solvents (wt%), and reaction time were chosen as independent variables for a central composite design (CCD). The optimal liquefaction conditions were as: 20 wt% of lignin, 3 wt% of catalyst at 5 min with yield and hydroxyl number of 95.27% and 537.95 mg KOH.g−1, respectively. Functional groups (measured by ATR-IR [attenuated total reflectance – infrared]) and the thermal degradation (TGA) of optimized bio-polyol and precipitated kraft lignin were determined.
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