Efficient depolymerization of sodium lignosulfonate assisted by sulfur migration

Lignosulfonate (LS), as the most abundant technical lignin, is hard to depolymerize due to highly condensed structure. To overcome the limitation, in this work, NiMoO 4 /Al 2 O 3 catalyst with regulated acidity/hydrogenation activity was developed for highly efficient LS depolymerization . Results show that the performance of NiMoO 4 /Al 2 O 3 was improved by sulfur migration. Meanwhile Ni Mo alloy contributed to the good stability during LS depolymerization . The NiMoO 4 /Al 2 O 3 was favor for the intermediate compounds production by the cleavage of C O and C C bonds, which intermediate compounds were eventually hydrogenated to monomers by highly active MoS 2 . Also, NiMoO 4 /Al 2 O 3 and sulfonic groups play a synergistic role in the sulfur migration (only 39.1% bio-oil yield obtained by MoS 2 /Al 2 O 3 ). After reacting at 300 °C for 4 h, 81.7% of bio-oil yield with 95% desulfurization rate were obtained. Thus, it was demonstrated that an inexpensive catalyst was developed which can efficiently catalyze the depolymerization of lignosulfonate.