Valorización de biomasa lignocelulósica mediante el uso de catalizadores basados en arcillas

Laburpena

In today's society there is a strong dependence on products derived from fossil fuels and it is convenient to reduce this dependence for the future of society. On the other hand, in the Tarragona area there is a presence of the agri-food industry related to nuts, with the consequent production of lignocellulosic waste, such as almond shells, which could be recovered to obtain chemical compounds with the same functions that they have today. petroleum derivatives. The main objective of the thesis is to provide added value to local biomass, specifically almond shells from the Tarragona region, through their fractionation and subsequent transformation into value-added products, such as furfural, tetrahydrofurfuryl alcohol, 5-hydroxymethylfurfural and the preparation of bituminous mixtures, using low-cost, clay-based catalysts. In this thesis, different clays such as delaminated mesoporous hectorites, fluorohectorites (in a new synthesis method) or commercial montmorillonite K10 have been prepared, modified their acid properties and characterized, which have subsequently been used as catalytic supports and as acid catalysts in the different reactions proposed. . The reaction conditions have been optimized in each case. The best yields of furfural from the xylose extract from biomass have been achieved with protonated delaminated hectorite reaching 90%, at 160 ºC microwave and 4 h of reaction. The highest selectivity to 5-hydroxymethylfurfural (62%) from glucose was achieved with a mixture of 44% by weight Amberlyst-15 and 56% by weight of montmorillonite K10 with 56% conversion at 140 ºC in autoclave and 4 h. of reaction. The highest yield of THFA from furfural obtained from the biomass xylose extract has been achieved with a Ni-Cu/mesoporous hectorite catalyst prepared with a molar ratio of Ni:Cu 1:1 with 90%, in the toluene phase, and 80% in the aqueous phase. Finally, lignins obtained from almond shells have been used as partial substitutes for bitumen in the preparation of bituminous mixtures, showing some interesting properties.