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Delignification of sugar cane bagasse: reactions, isolation and use of lignins.

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Karen Marabezi
Total Authors: 1
Document type: Doctoral Thesis
Press: São Carlos.
Institution: Universidade de São Paulo (USP). Instituto de Química de São Carlos
Defense date:
Examining board members:
Antonio Aprigio da Silva Curvelo; Mauricio Boscolo; Antonio José Felix de Carvalho; Marcelo Henrique Gehlen
Advisor: Antonio Aprigio da Silva Curvelo

The use of plant biomass as a feedstock for the production of chemicals requires pre-treatments which lead to disruption of the lignocellulosic complex, the main challenge being selective and quantitative removal of lignin. Sugarcane bagasse is a lignocellulosic material composed of cellulose, lignin and polyoses as major macromolecular components, and has been the subject of research for bioethanol production and products with higher added value. The heterogeneity of lignins obtained as byproducts of delignification processes is one reason for the limitation of possible industrial applications. However, recent developments in cellulosic ethanol will raise the amount of lignin available on a global basis. These forward-looking statements have renewed interest in the isolation and conversion of lignin in chemical products with higher added value. In this sense, the isolation and characterization of lignins is of fundamental importance. We present the results of studies of delignification of sugarcane bagasse by applying different pulping processes (Soda, Sulfite and organosolv ethanol / water processes). These processes were evaluated according to the performance of pre-treatment and selectivity against macromolecular components of lignocellulosic materials. The second stage of the work describes the characterization of lignins obtained in different pulping processes, aiming to further modifications and applications as oxidized derivatives and the preparation of new polymeric materials thermoplastic and / or thermosetting. Processes produced different lignins, and these differences in distribution of molecular weight, amount of hydroxyls, thermal stability and amount of impurities. The use of solvent fractionation was effective in getting different molar masses and lower polydispersities. The conditions employed in esterification reaction produced polymers with different characteristics, such as viscosity, glass transition temperature and thermal stability. (AU)

FAPESP's process: 09/10433-6 - Delignification of Sugarcane Bagasse: Reactions, Isolation and Use of Lignin
Grantee:Karen Marabezi
Support type: Scholarships in Brazil - Doctorate