Reaction Mechanisms in Pyrolysis of Hardwood, Softwood, and Kraft Lignin Revealed by ReaxFF MD Simulations

doi:10.1021/acs.energyfuels.9b02843

	Reaction Mechanisms in Pyrolysis of Hardwood, Softwood, and Kraft Lignin Revealed by ReaxFF MD Simulations
	Zhang, Tingting 1,3; Li, Xiaoxia 1,3; Gao, Li 1,3; Guo, Xin 2
刊名	ENERGY & FUELS
	2019-11-01
卷号	33 期号:11 页码:11210-11225
ISSN号	0887-0624
DOI	10.1021/acs.energyfuels.9b02843
英文摘要	Reactions of linkages and monomer rings in hardwood, softwood, and kraft lignin pyrolysis were investigated using reactive force field (ReaxFF) molecular dynamics (MD) simulations. Four large lignin models with diverse linkages and oxygen-containing groups were constructed on the basis of the two-dimensional lignin models proposed by Adler and Freudenberg for softwood lignin, by Nimz for hardwood lignin, and by Marton for kraft lignin. Large-scale ReaxFF MD simulations were performed using the GMD-Reax code and analyzed with the VARxMD code. The breaking of C-alpha/C-beta-O bonds in alpha/beta-O-4 linkages is the dominant pathway to convert the source lignin molecules into smaller fragments. Differences in pyrolyzate evolution and linkage behavior among hardwood, softwood, and kraft lignin can be attributed to different reactions of linkages and their linked monomers induced by their varied oxygen-containing substituents. The consumption evolution of beta-O-4 linkages can be promoted by their active substituents (C-alpha=O and C-alpha-O-4). The conversion of beta-beta_gamma-O-alpha linkages and their linked monomer rings can be accelerated by the C-alpha=O substituent on the beta-beta_gamma-O-alpha linkages and by the substituents of C-alpha-O-4 and OCH3 on the monomer ring. The different evolution profiles of the softwood, hardwood, and kraft lignin models are caused by the differences in the inherent structures (mainly linkage and oxygen-containing functional groups) of lignin from different tree species or isolation methods. Despite distinct differences in the pyrolyzate evolutions and linkage behaviors, the ring substructure evolutions of five- to seven-membered rings are similar for the four lignin models. This work demonstrates a useful alternative approach for investigating the pyrolysis reaction mechanism of lignin from varied sources.
资助项目	Foundation of State Key Laboratory of Coal Combustion[FSKLCCA1903] ; Strategic Priority Research Program of the Chinese Academy of Sciences[XDA21030700] ; Strategic Priority Research Program of the Chinese Academy of Sciences[XDA21040400] ; National Natural Science Foundation of China[91434105] ; National Natural Science Foundation of China[21373227]
WOS关键词	BOND-DISSOCIATION ENTHALPIES ; FORCE-FIELD ; INITIAL REACTIVITY ; COAL PYROLYSIS ; MODEL ; BEHAVIOR ; CHEMISTRY ; OXIDATION ; LINKAGES ; POLYMERS
WOS研究方向	Energy & Fuels ; Engineering
语种	英语
出版者	AMER CHEMICAL SOC
WOS记录号	WOS:000499741900079
资助机构	Foundation of State Key Laboratory of Coal Combustion ; Strategic Priority Research Program of the Chinese Academy of Sciences ; National Natural Science Foundation of China
内容类型	期刊论文
源URL	[http://ir.ipe.ac.cn/handle/122111/38273]
专题	中国科学院过程工程研究所
通讯作者	Li, Xiaoxia
作者单位	1.Chinese Acad Sci, Inst Proc Engn, State Key Lab Multiphase Complex Syst, 1 Zhongguancun North Second St, Beijing 100190, Peoples R China 2.Huazhong Univ Sci & Technol, State Key Lab Coal Combust, Wuhan 430074, Hubei, Peoples R China 3.Univ Chinese Acad Sci, Sch Chem Engn, Beijing 100049, Peoples R China
推荐引用方式 GB/T 7714	Zhang, Tingting,Li, Xiaoxia,Gao, Li,et al. Reaction Mechanisms in Pyrolysis of Hardwood, Softwood, and Kraft Lignin Revealed by ReaxFF MD Simulations[J]. ENERGY & FUELS,2019,33(11):11210-11225.
APA	Zhang, Tingting,Li, Xiaoxia,Gao, Li,&Guo, Xin.(2019).Reaction Mechanisms in Pyrolysis of Hardwood, Softwood, and Kraft Lignin Revealed by ReaxFF MD Simulations.ENERGY & FUELS,33(11),11210-11225.
MLA	Zhang, Tingting,et al."Reaction Mechanisms in Pyrolysis of Hardwood, Softwood, and Kraft Lignin Revealed by ReaxFF MD Simulations".ENERGY & FUELS 33.11(2019):11210-11225.