| Autor: |
Zeng, Xu, Akiyama, Takuya, Yokoyama, Tomoya, Matsumoto, Yuji |
| Předmět: |
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| Zdroj: |
Journal of Wood Chemistry & Technology; 2020, Vol. 40 Issue 5, p348-360, 13p |
| Abstrakt: |
The most common non-phenolic β-O-4-type lignin model compounds with or without the γ-hydroxymethyl group (C6-C3- or C6-C2-type, respectively) were treated in a 0.5 mol/L potassium tert-butoxide in DMSO solution at 30 °C to examine the effects of presence of the group. The β-O-4 bond of the C6-C3-type cleaved more rapidly than the C6-C2-type, indicating that the γ-hydroxy group contributes to the cleavage, in contrast to their reactions in alkaline pulping processes. Furthermore, the β-O-4 bond of the threo isomer of the C6-C3-type cleaved more rapidly than that of the erythro isomer. This result can be attributed to the fact that the erythro isomer has the hydrogen bond between a generated alkoxide and the other hydroxy group at its α- and γ-positions in its most-preferential conformer, interfering with the β-O-4 bond cleavage. It was also suggested in treatments of their methyl-etherified derivatives at the α- or γ-hydroxy group that the contribution of the γ-hydroxy group of the threo isomer is greater than that of the erythro isomer. Detailed examination of the distribution profile of reaction products supported this greater contribution of the γ-hydroxy group of the threo isomer. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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