Pyrolysis reactions of various lignin model dimers
Pyrolysis reactions of various lignin model dimers
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DOI：
10.1007/s10086-006-0834-z
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发表时间：
2007-04-01
影响因子：
2.9
通讯作者：
Saka, Shiro
中科院分区：
文献类型：
--
作者：
Kawamoto, Haruo;Horigoshi, Sunao;Saka, Shiro
通过表征在400 ℃下热解后获得的四氢呋喃（THF）可溶性和THF不溶性级分，对具有α-O-4、β-O-4、β-1和联苯亚结构的各种木质素模型二聚体的主要热解反应和解聚和缩合/碳化的相对反应性进行了评价。反应性因模型结构而异：解聚：α-O-4 [酚（ph），非酚（nonph）]，β-O-4（ph）> β-O-4（nonph），β-1（ph，nonph）>联苯（ph，nonph）;缩合/碳化：β-1（ph）> β-O-4（ph）> α-O-4（ph）> β-O-4（nonph），联苯（ph，nonph），α-O-4（nonph），β-1（nonph）。还确定了β-O-4和β-1模型二聚体的主要降解途径：β-O-4型：C-β-O裂解形成肉桂醇和苯酚，C-γ消除产生乙烯基醚; β-1型：C-α-C-β裂解产生苯甲醛和苯乙烯，C-γ消除产生二苯乙烯。这些途径的相对反应性在酚类和非酚类形式之间也有很大差异，即使在相同的类型中; C-β-O裂解（β-O-4）和C-γ-消除（β-1）在酚类形式中大大增强。
Primary pyrolysis reactions and relative reactivities for depolymerization and condensation/carbonization were evaluated for various lignin model dimers with alpha-O-4, beta-O-4, beta-1, and biphenyl substructures by characterizing the tetrahydrofuran (THF)-soluble and THF-insoluble fractions obtained after pyrolysis at 400 degrees C. Reactivity was quite different depending on the model structure: depolymerization: alpha-O-4 [phenolic (ph), nonphenolic (nonph)], beta-O-4 (ph) > beta-O-4 (nonph), beta-1 (ph, nonph) > biphenyl (ph, nonph); condensation/carbonization: beta-1 (ph) > beta-O-4 (ph) > alpha-O-4 (ph) > beta-O-4 (nonph), biphenyl (ph, nonph), alpha-O-4 (nonph), beta-1 (nonph). Major degradation pathways were also identified for beta-O-4 and beta-1 model dimers: beta-O-4 types: C-beta-O cleavage to form cinnamyl alcohols and phenols and C-gamma-elimination yielding vinyl ethers; beta-1 types: C-alpha-C-beta cleavage yielding benzaldehydes and styrenes and C-gamma-elimination yielding stilbenes. Relative reactivities of these pathways were also quite different between phenolic and nonphenolic forms even in the same types; C-beta-O cleavage (beta-O-4) and C-gamma-elimination (beta-1) were substantially enhanced in phenolic forms.