Studies on the dehydrogenative polymerizations (DHPs) of monolignol β-glycosides:: Part 4.: Horseradish peroxidase-catalyzed copolymerization of isoconiferin and isosyringin
Studies on the dehydrogenative polymerizations (DHPs) of monolignol β-glycosides:: Part 4.: Horseradish peroxidase-catalyzed copolymerization of isoconiferin and isosyringin
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DOI：
10.1515/hf.2008.093
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发表时间：
2008-09-01
期刊：
影响因子：
2.4
通讯作者：
Nakatsubo, Fumiaki
中科院分区：
文献类型：
--
作者：
Tobimatsu, Yuki;Takano, Toshiyuki;Nakatsubo, Fumiaki
辣根过氧化物酶（HRP）催化愈创木基（G）型单体木质醇糖苷（异松柏苷，松柏醇γ-O-β-D-吡喃葡萄糖苷，iso-G）和紫丁香基（S）型单体木质醇糖苷（异丁香苷，芥子醇γ-O-β-D-吡喃葡萄糖苷，iso-S）的脱氢共聚反应在连续脱氢模式（末端聚合）导致在均相中形成水溶性木质素类共聚物（isoG/S-DHP）。随着单体混合物中iso-G含量的增加，iso-G/S-DHP的产率从23%（iso-G/iso-S 0:100）增加到81%（iso-G/iso-S 50:50）。随着iso-G含量的增加，所得iso-G/S-DHP的聚合度(DP)也按比例从7(iso-G/iso-S 0:100)增加到27(iso-G/iso-S 50:50)。显然，iso-G 在 iso-S 的聚合中起着重要的作用。在松柏醇（G-alc）和芥子醇（S-alc）的常规共聚中也观察到类似的趋势。传统系统中 DHP 获得的最高 DP 仅为； 10 由于非均相反应体系。由于添加 iso-G 作为共聚单体大大提高了 iso-S 的 HRP 催化单体消耗率，因此从 iso-G 到 iso-S 的自由基转移似乎是合理的。 G-alc和S-alc的常规共聚也支持这一观点。光谱研究和碱性硝基苯氧化分析表明iso-G/S-DHPs 具有典型的由G 和S 单元组成的木质素结构。已证实，均相中糖苷 iso-G 和 iso-S 的共聚行为很好地反映了异相中木质素单体 G-alc 和 S-alc 的共聚行为。结果还表明，G 型共聚单体的存在敏感地影响 S 型单体的聚合。
Horseradish peroxidase (HRP)-catalyzed dehydrogenative copolymerization of guaiacyl (G)-type monolignol glycoside (isoconiferin, coniferyl alcohol gamma-O-beta-D-glucopyranoside, iso-G) and syringyl (S)-type monolignol glycoside (isosyringin, sinapyl alcohol gamma-O-beta-D-glucopyranoside, iso-S) were performed in continuous dehydrogenation mode (end-wise polymerization) to result in the formation of water-soluble lignin-like copolymers (isoG/S-DHPs) in a homogeneous phase. The yield of iso-G/S-DHP increased with increasing iso-G content in the mixture of monomers from 23% (iso-G/iso-S 0: 100) to 81% (iso-G/iso-S 50: 50). The degree of polymerization (DP) of the resulting iso-G/S-DHP also increased proportionally from 7 (iso-G/iso-S 0: 100) to 27 (iso-G/iso-S 50:50) as the iso-G content increased. It is obvious that iso-G plays an important role in the polymerization of iso-S. A similar tendency was also observed in conventional copolymerization of coniferyl alcohol (G-alc) and sinapyl alcohol (S-alc). The highest DP for DHP obtained in the conventional system was only; 10 due to the heterogeneous reaction system. As the HRP-catalyzed monomer consumption rate of iso-S was greatly enhanced by addition of iso-G as a co-monomer, radical transfer from iso-G to iso-S seems to be plausible. Conventional copolymerization of G-alc and S-alc also supports this view. Spectroscopic studies and alkaline nitrobenzene oxidation analyses indicated that iso-G/S-DHPs had typical lignin structures composed of both G and S units. It was confirmed that the copolymerization behavior of the glycosides iso-G and iso-S in a homogeneous phase are well reflected by that of the monolignols G-alc and S-alc in a heterogeneous phase. Results also indicated that the presence of G-type co-monomers sensitively affects the polymerization of S-type monomers.