Catalytic Ethanolysis of Enzymatic Hydrolysis Lignin over an Unsupported Nickel Catalyst : The Effect of Reaction Conditions

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A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä

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en

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10

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Energy & Fuels, Volume 35, issue 1, pp. 519-528

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The effect of reaction conditions on ethanolysis of enzymatic hydrolysis lignin (EHL) with an unsupported nickel catalyst, that is, Ni(220H), was investigated. The two-dimensional heteronuclear single quantum coherence-nuclear magnetic resonance (2D-HSQC NMR) analysis of liquid products revealed that both the ether and C-C linkages in EHL were cleaved during the reaction and the ether linkages were completely cleaved under mild reaction conditions, while the cleavage of C-C linkages needed harsh reaction conditions. At 280 °C under 2 MPa H2 within 6 h, the highest aromatic monomer yield of 28.5 wt % was achieved. Further increasing the reaction temperature to 300 °C or decreasing the initial hydrogen pressure to 0 MPa was conducive to the repolymerization reaction. The ortho-alkyl phenol monomers originated from the alkyl free radicals produced from ethanol. Under 0 MPa H2, the hydrogenation of -HCCH- in side chains was inefficient, and hence, the decarboxylation and alkenyl elimination reactions of side chains were favorable.

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Sang, Y, Wu, K, Liu, Q, Bai, Y, Chen, H & Li, Y 2021, 'Catalytic Ethanolysis of Enzymatic Hydrolysis Lignin over an Unsupported Nickel Catalyst : The Effect of Reaction Conditions', Energy & Fuels, vol. 35, no. 1, pp. 519-528. https://doi.org/10.1021/acs.energyfuels.0c02848