Effect of grafting solvent in the optimisation of Sba-15 acidity for levulinic acid production

Valorisation of lignocellulosic biomass for chemical production is one of the main challenges of the 21st century. Levulinic acid (LA) has been chosen as the target product due to its potential as an intermediate to produce a wide variety of other chemicals. The attention has been focused on the formulation of an active solid acid catalyst for the hydrolysis of glucose to LA. Therefore, a deep modification of SBA-15 with sulfonic groups was performed using post-synthesis grafting method. In particular, this work focuses on the role of different grafting solvents. Since the traditional solvents such as toluene or hexane, are flammable and toxic, a safer and more environmentally friendly solvent, a mixture of water and NaCl has been investigated. It was found that the nature of the solvent highly affects the morphological and chemical features of the materials. Thus, the best catalytic results were obtained with the catalyst prepared in water and NaCl; indeed 30 % and 16 % of LA yield were obtained from fructose and glucose hydrolysis at 180 °C respectively. Water and NaCl mixture guarantees the best distribution of sulfonic groups over the surface, leading to the most balanced acid catalyst.