lignin linkage

  • 文章类型: Journal Article
    限制树皮工业用途的一个主要因素是其与木材相比更大的顽抗性。虽然木质素被广泛认为是一个重要的贡献者,树皮中木质素的精确表征仍然稀疏,提出了一个关键的差距,阻碍了对其影响的理解。在这项研究中,我们采用先进的固态核磁共振(NMR)光谱来分析来自不同物种的树皮样品,包括柳树,杨树,和松树。我们建立并验证了56ppm的木质素甲氧基峰作为评估木质素含量的可靠定量指标,与木材相比,我们计算出树皮中的木质素含量显着降低了70%以上。此外,原位表征显示树皮木质素中β-醚键显著减少,揭示了一个更浓缩和抵抗的结构配置。我们的结果大大加深了我们对树皮中天然木质素的组成和结构的理解。
    A major factor limiting bark\'s industrial use is its greater recalcitrance compared to wood. While lignin is widely recognized as a significant contributor, precise characterization of lignin in bark remains sparse, presenting a crucial gap that impedes understanding of its impact. In this study, we employed advanced solid-state nuclear magnetic resonance (NMR) spectroscopy to analyze bark samples from various species, including willow, poplar, and pine. We established and verified that lignin methoxy peak at 56 ppm serves as a reliable quantitative metric to assess lignin content, with which we calculated the lignin contents in bark are significantly reduced by more than 70% compared to those in wood. Furthermore, in situ characterization revealed significant reduction of β-ether linkage in bark lignin across species, revealing a more condensed and resistant structural configuration. Our results have substantially advanced our comprehension of the composition and structure of native lignin in tree bark.
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  • 文章类型: Journal Article
    自催化的乙醇有机溶剂工艺越来越受到木质素无硫分离的关注,随后被用作各种基于化石的应用的可再生替代品。第一次,研究了两种不同生物质的七个不同粒径对各自的有机溶剂木质素结构的机械化学影响。葡萄酒修剪(黑皮诺)和葡萄酒果渣(Accent)用于有机溶剂工艺,粒径范围为2.0-1.6mm至小于0.25mm。随着颗粒尺寸的减小,重均分子量增加,而总酚含量显著下降。此外,木质素典型的单木素和相关子结构的分布,通过二维异核核磁共振谱确定单量子相干(HSQC),被观察到。生物质的研磨程度对分离的HG和HGS有机溶剂木质素具有明显的化学结构影响。因此,有针对性地应用有机溶剂木质素,了解这种影响是至关重要的。在未来,在有机溶剂法的上下文中,粒度规格应当以分布密度而不是以小于规格的方式来表示。本文受版权保护。保留所有权利。
    The autocatalyzed ethanolic organosolv process is gaining increasing attention for the sulfur-free isolation of lignin, which is subsequently used as a renewable substitute for various fossil-based applications. For the first time, the mechanochemical influence of seven different particle sizes of two different biomasses on the respective organosolv lignin structure is examined. Wine pruning (Pinot Noir) and wine pomace (Accent) are used for organosolv process with particle sizes ranging from 2.0-1.6 mm to less than 0.25 mm. As particle size decreases, the weight-average molecular weight increases, while the total phenol content decreases significantly. Additionally, the distribution of the lignin-typical monolignols and relevant substructures, as determined by two-dimensional heteronuclear nuclear magnetic resonance spectra single quantum coherence (HSQC), is observed. The degree of grinding of the biomass has a clear chemical-structural influence on the isolated HG and HGS organosolv lignins. Therefore, it is crucial to understand this influence to apply organosolv lignins in a targeted manner. In the future, particle size specifications in the context of the organosolv process should be expressed in terms of distribution densities rather than in terms of a smaller than specification.
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