Lignina da bioraffineria : isolamento, caratterizzazione e possibili derivatizzazioni

Through the integration of green chemistry into biorefneries and the use of low environmental impact technologies, future sustainable production chains of biofuels and high value chemicals from biomass could quickly forecast. Despite the fact that a massive amount of lignin is obtained from the biorefineries, the use of lignin in real industrial processes is far to be obtained. Hence approaches to develop lignin conversion into high-value co-products are progressively investigated in the attempt to improve the economics of the biorefineries. Firstly, lignin isolation and extraction was studied in the sense of the enhancement of lignin production as well as trying to extract lignin with optimum physicochemical properties for its valorization. The isolation of lignin from the selective precipitation of the black liquor resulting from the pulping of the starting material in soda was performed. The pH is a variable of large influence on the precipitation of the lignin and its physicochemical properties. Decreasing the pH until 4 resulted in a huge increase of precipitated lignin mass. Although that understanding the structure and the biosynthetic pathway of lignin is challenging, the recovered material and the lignocellulosic polymers were fully characterized.Then, two main possible application of the isolated lignin were studied: the conversion of lignin to low-molecular-weight aromatic/phenolic compounds by a catalytic fragmentation-hydrogenolysis process and the evaluation of lignin in adhesive production without using formaldehyde.