Catalytic depolymerization of the dealkaline lignin over Co-Mo-S catalysts in supercritical ethanol

In this work, lignin depolymerization was examined over CoMo sulfide catalysts supported on different carriers in supercritical ethanol system. The temperature, time, MoS2 and carrier effects on the lignin depolymerization were investigated. 95.76% liquefaction yield with negligible char was achieved over Co-Mo-S/ZrO2 at 340 degrees C for 150 min. The liquid product was mainly composed of C-4-C-8 alcohols, C-4-C-10 esters and C-7-C-10 aromatic compounds. The synergistic effect of active sites and acid-base sites on support played an important role in lignin depolymerization. Furthermore, the Co-Mo-S/ZrO2 catalyst is reusable with 8% loss in liquefaction yield after 5 cyclic runs. We believe that acid/base carriers or additives that can promote the medium to generate abundant free radicals or ions to replace external hydrogen pressure are one of the prospects for the design of depolymerization lignin catalysts.

Automated summary

This study investigated the depolymerization of lignin using CoMo sulfide catalysts supported on different carriers in a supercritical ethanol system. The effects of temperature, time, MoS2, and carrier on the lignin depolymerization were examined. The Co-Mo-S/ZrO2 catalyst showed a liquefaction yield of 95.76% with minimal char formation at 340 degrees C for 150 minutes. The liquid product mainly consisted of C-4-C-8 alcohols, C-4-C-10 esters, and C-7-C-10 aromatic compounds. The synergistic effect of active and acid-base sites on the support played a crucial role in the lignin depolymerization process.