Reductive Hydroprocessing of Hydrolysis Lignin over Efficient Bimetallic Catalyst MoRu/AC

Abstract

The fast-growing demand for renewable fuels and chemicals, together with environmental concern, has inspired the study of lignin. However, the valorization of lignin is challenged by its large molecular structure and oxygen content. Catalytic hydroprocessing of lignin is the effective depolymerization for producing fuels and chemicals. The aims of this work were the implementation and study of the role of a novel and inexpensive bimetallic catalyst, MoRu/AC, in the reductive depolymerization (hydroprocessing) of hydrolysis lignin. The increase in the reaction temperature, between 200 and 340 °C, dramatically enhanced the hydrogen content of the bio-oils relative to the feed. The MoRu/AC catalyst exhibited excellent activity in the hydrogenation and produced bio-oils with a substantially increased H/C ratio, suggesting enhanced hydrodeoxygenation activity of the MoRu/AC. The catalyst at optimum temperature, 340 °C, significantly promoted the hydrogenation, and the H content in the bio-oil was 1.5 times of that in the feed. The results demonstrated that the phenolic compounds were the main component in all the produced biooils. This confirms that hydrolysis lignin can be easily depolymerized at the temperature range of 200−340 °C in the presence of the MoRu/AC catalyst.

Sustainable biomass hydrodeoxygenation in biphasic systems

“…8b. 127 The excellent deoxygenation performance of the carbon-loaded catalyst resulted in a significant increase in the H/C ratio of the product (∼0.25 increase compared with an unchanged H/C ratio with Ru/C). Molecular dynamics studies have shown that the catalyst lowers the debonding energy barrier of the ether group, resulting in a significant increase in reactivity.…”

“…120 (b) The selective HDO of lignin to low molecular weight bio-oil over a Mo-Ru/AC catalyst. 127 Fig. 9 High-value utilization routes of furans.…”

Evaluation of kraft and hydrolysis lignin hydroconversion over unsupported NiMoS catalyst

“…Compared to Kraft lignin, hydrolysis lignin, containing less ash and sulfur, can be produced from conversion of lignocellulosic biomass during enzymatic hydrolysis, which results in solid lignin (≥60 wt%), and unreacted cellulose [15]. However, limited studies have investigated catalytic reductive depolymerization of enzymatic hydrolysis lignin.…”

Bioconversion of Lignin-Derived Feedstocks to Muconic Acid by Whole-Cell Biocatalysis

“…For instance, the content of the guaiacyl unit in grass and broadleaf wood is 20–50%, whereas its content could reach 90–95% in coniferous wood; the content of the syringyl unit in broadleaf wood is approximately 50–75%, while the content of the p -hydroxyphenyl unit in grass is only 10–25% . Lignin represents one of most abundant feedstocks on earth, accounting for 10–30 wt % of lignin cellulose biomass, and its availability is estimated to be more than 300 billion tons. − Lignin as a byproduct can be obtained from agricultural wastes and biorefinery, and its total mass is estimated to exceed 100 million tons per year. , The chemical structure and the richness of lignin render it a promising feedstock for renewable aromatic monomers. − Currently, there are a number of chemical approaches such as catalytic degradation and thermochemical treatment for lignin valorization. , For instance, isoeugenol can be produced in ≤60% yield during the cleavage of β-aryl ethers in lignin by alcohol bisulfite treatment …”