Hydrodeoxygenation of Lignin-Derived Aromatic Oxygenates Over Pd-Fe Bimetallic Catalyst: A Mechanistic Study of Direct C–O Bond Cleavage and Direct Ring Hydrogenation

• Published in: Catalysis letters Vol. 151; no. 4; pp. 932 - 939
• Main Authors: Zhang, Jianghao, Sudduth, Berlin, Sun, Junming, Wang, Yong
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.04.2021; Springer; Springer Nature B.V
• Subjects: Activation energy; Analysis; Bimetals; Bonds; Catalysis; Catalysts; Chemistry; Chemistry and Materials Science; Cleavage; Comparative studies; Hydrogenation; Industrial Chemistry/Chemical Engineering; Lignin; Liquid phases; Organometallic Chemistry; Palladium; Palladium catalysts; Phenols; Physical Chemistry; C–O bond cleavage; Mechanistic study; Aromatic oxygenate; Pd–fe catalyst; Direct ring hydrogenation
• ISSN: 1011-372X; 1572-879X
• DOI: 10.1007/s10562-020-03352-3

Hydrodeoxygenation of lignin-derived phenols could be achieved generally with three reaction pathways: tautomerization, direct ring hydrogenation and direct C–O bond cleavage. The former pathway has been extensively studied over Pd/Fe catalyst in liquid-phase reaction, however, the contribution of the latter two is yet subject to further investigations. In this report, a comparative study of direct C–O bond cleavage and direct ring hydrogenation reaction pathways is presented on Pd/Fe, Fe and Pd/C catalysts using diphenyl ether as modelling compound. Despite its much higher activation energy than direct ring hydrogenation, direct C–O bond cleavage is dominant over Pd/Fe with much higher rates than the monometallic analogues due to the synergic catalysis of Pd–Fe. Based on this study and our previous results, the detailed reaction network for HDO of diphenyl ether is proposed. Graphic Abstract