title: Lignin hydrolysis and phosphorylation mechanism during phosphoric acid-acetone pretreatment: a DFT study.
abstract: The study focused on the structural sensitivity of lignin during the phosphoric acid-acetone pretreatment process and the resulting hydrolysis and phosphorylation reaction mechanisms using density functional theory calculations. The chemical stabilities of the seven most common linkages (β-O-4, β-β, 4-O-5, β-1, 5-5, α-O-4, and β-5) of lignin in H3PO4, CH3COCH3, and H2O solutions were detected, which shows that α-O-4 linkage and β-O-4 linkage tend to break during the phosphoric acid-acetone pretreatment process. Then α-O-4 phosphorylation and β-O-4 phosphorylation follow a two-step reaction mechanism in the acid treatment step, respectively. However, since phosphorylation of α-O-4 is more energetically accessible than phosphorylation of β-O-4 in phosphoric acid, the phosphorylation of α-O-4 could be controllably realized under certain operational conditions, which could tune the electron and hole transfer on the right side of β-O-4 in the H2PO4- functionalized lignin. The results provide a fundamental understanding for process-controlled modification of lignin and the potential novel applications in lignin-based imprinted polymers, sensors, and molecular devices.
authors.affiliation: National Engineering Laboratory for Biomass Power Generation Equipment, School of Renewable Energy Engineering, North China Electric Power University, Beijing 102206, China. qinwugx@126.com.
authors.forename: Wu
authors.initials: W
authors.lastname: Qin
authors.affiliation: National Engineering Laboratory for Biomass Power Generation Equipment, School of Renewable Energy Engineering, North China Electric Power University, Beijing 102206, China.
authors.forename: Lingnan
authors.initials: L
authors.lastname: Wu
authors.affiliation: National Engineering Laboratory for Biomass Power Generation Equipment, School of Renewable Energy Engineering, North China Electric Power University, Beijing 102206, China. zmzheng@vip.126.com.
authors.forename: Zongming
authors.initials: Z
authors.lastname: Zheng
authors.affiliation: National Engineering Laboratory for Biomass Power Generation Equipment, School of Renewable Energy Engineering, North China Electric Power University, Beijing 102206, China.
authors.forename: Changqing
authors.initials: C
authors.lastname: Dong
authors.affiliation: National Engineering Laboratory for Biomass Power Generation Equipment, School of Renewable Energy Engineering, North China Electric Power University, Beijing 102206, China.
authors.forename: Yongping
authors.initials: Y
authors.lastname: Yang
mesh_terms: D000096:Acetone / Q000737:chemistry*; D002236:Carbohydrate Conformation; D006868:Hydrolysis; D008031:Lignin / Q000737:chemistry*; D008956:Models, Chemical; D010756:Phosphoric Acids / Q000737:chemistry*; D010766:Phosphorylation; D011789:Quantum Theory; D012996:Solutions; D013816:Thermodynamics
chemical_list: D010756:Phosphoric Acids; D012996:Solutions; D000096:Acetone; D008031:Lignin; C030242:phosphoric acid