首页|Pyrolysis mechanism law of β-O-4 lignin dimer model compounds: A density functional theory study
Pyrolysis mechanism law of β-O-4 lignin dimer model compounds: A density functional theory study
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NSTL
Elsevier
? 2022 Elsevier B.V.Lignin is the second abundant natural renewable after cellulose. Pyrolysis is usually transformed lignin into high value-added platform compounds. In order to fully utilized lignin, the pyrolysis mechanism needs an in-depth understanding. Herein we performed density function theory (DFT) calculation to unveil the initial mechanism of pyrolysis of 9 representative β ? O? 4 lignin dimer model compounds with phenyl-1, 3-propanediol as the main body. Several cleavage pathways were investigated, including Cβ?O bond breaking（Cβ?O bond homolysis reaction, Maccoll elimination reaction and retro-ene fragmentation reaction） and Cα?Cβ bond breaking. Results show that the substituents on the B-ring have a greater effect on the pyrolysis pathway of lignin dimer than that on the A-ring. When no substituent on the ortho-position of B-ring, the retro-ene fragmentation reaction is the dominant pathway. And, its main reason is these structures have no steric hindrance in the process of hydrogen transfer. The Cβ?O bond homolysis is the dominant pathway when methoxy group exists on ortho-position of B-ring. Maccoll elimination reaction also has certain advantages due to the influence of electronic factors of methoxyl group on ortho-position of B-ring. The cleavage reaction of Cβ?O bond is always prior to that of Cα?Cβ bond. The effect of water molecules on the pyrolysis reaction has been also discussed. The results showed that H2O could promote the Maccoll elimination I reaction, but did not change the dominant pyrolysis mechanism.
Density functional theoryLigninPyrolysis lawβ-O-4 dimer
Yu H.、Wang S.、Sun Y.、Zhang W.、Li R.、Kang X.
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Shenyang Aerospace University Liaoning Key Laboratory of Clean Energy
NSTL
Elsevier
