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35 results on '"Wei, Junnan"'

17. A unique air-assisted DMSO oxidation pathway for the highly efficient synthesis of 2,5-diformylfuran from 5-hydroxymethylfurfural/fructose.

Author

Pang, Yujia, Chen, Ning, Zhao, Zhizhou, Zhang, Lei, Broekman, J. O. P., Wei, Junnan, Li, Xiujuan, Lin, Lu, and Huang, He

Subjects
CHEMICAL systems, DENSITY functional theory, OXIDATION, BIOMASS chemicals, HYDROXYMETHYLFURFURAL, CATALYTIC activity, FRUCTOSE
Abstract

The development of safe, economical and highly efficient oxidation systems for the production of chemicals from biomass remains a significant and challenging target. Here, we first found a unique air-assisted reaction mechanism for the non-pressurized oxidation of 5-hydroxymethylfurfural (HMF) to 2,5-diformylfuran (DFF) using dimethylsulfoxide (DMSO) as an O-donor over CoZrNC-MCM, which affords exceptional productivity among all non-noble catalysts. The combination of control experiments and density functional theory (DFT) calculations reveals that the air-assisted DMSO oxidation pathway is activated by the co-adsorption of DMSO and O2 on Co-(pyrrolic N–C) pairs of CoNC-MCM. ZrNC species in CoZrNC-MCM will be thermally disintegrated to release ZrO2+ and provide the corresponding cation vacancies that might be able to capture Co atoms to form additional Co-(pyrrolic N–C) active pairs, resulting in the increase of catalytic activity. The released ZrO2+ is well dispersed over Al-MCM-41 in the form of zirconia, which contributes to the dehydration of fructose to HMF. In this way, a one-step approach for synthesizing DFF from fructose is achieved by the cooperation of zirconia and Co-(pyrrolic N–C) pairs over CoZrNC-MCM. [ABSTRACT FROM AUTHOR]

Published
2023
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35. Hydrogenation of methyl levulinate to γ‐valerolactone over Cu─Mg oxide using MeOH as in situ hydrogen source.

Author

Cao, Xuejuan, Wei, Junnan, Liu, Huai, Lv, Xinyue, Tang, Xing, Zeng, Xianhai, Sun, Yong, Lei, Tingzhou, Liu, Shijie, and Lin, Lu

Subjects
HYDROGENATION, HYDROLYSIS, METHANOLYSIS, CELLULOSE, CATALYSIS
Abstract

BACKGROUND γ‐Valerolactone (GVL) is a versatile biomass‐derived platform molecule that could serve as a building block to produce chemicals, materials and fuels, but the production of GVL from biomass via a cost‐competitive method is challenging. In this contribution, a robust Cu─Mg oxide was prepared as an efficient bifunctional catalyst for both H2 production by MeOH reforming and hydrogenation of methyl levulinate (ML) to GVL in MeOH medium. RESULTS: Cu0.87Mg0.13Ox prepared by a urea hydrolysis method offered a GVL yield up to 90.6% at 220°C in 4 h without external hydrogen. This catalyst could be reused for at least seven consecutive cycles without loss of its activity. Notably, Cu0.87Mg0.13Ox also provided nearly 70% GVL yield in methanolysis products of cellulose in the presence of humins. Characterization of the catalyst indicates that the incorporation of MgO greatly facilitates the stabilization of Cu+ species that possess a better catalytic performance in ML hydrogenation compared with metallic Cu. CONCLUSION: This robust Cu0.87Mg0.13Ox could greatly contribute to develop a highly facile and desirable two‐step strategy for GVL production from cellulose, through the integration of ML production by methanolysis of cellulose, H2 formation by MeOH reforming and ML hydrogenation in MeOH medium. © 2018 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Published
2019
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