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首页> 外文会议>ACS National Meeting Exhibition >MECHANISMS OF FORMALDEHYDE GENERATION FROM WOOD AND IMPLICATIONS TO BIOMASS TREATMENT
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MECHANISMS OF FORMALDEHYDE GENERATION FROM WOOD AND IMPLICATIONS TO BIOMASS TREATMENT

机译：从木材中产生的甲醛生成的机制，对生物质处理的影响

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In the realm of non-structural wood-based composites, the stringency of new formaldehyde emissions regulations makes necessary a complete accounting of all formaldehyde sources, synthetic and biogenic. Research in our lab has considered lignin's contribution to biogenic formaldehyde formation via the hypothetical reaction pathway shown in Figure 1. It is known, and we have further demonstrated, that common industrial heating processes stimulate formaldehyde generation and emission. The implications in the wood-based composites industry are great; but perhaps those for the future biofuels industry have not been considered. Extensive lignin model compound studies reveal two acidolysis pathways with one of them generating formaldehyde. As these studies suggested, acid types influence the acidolysis pathway, perhaps due to the acid counter ion size effects. In light of this, we applied different acids into solid wood, and demonstrated their capabilities to manipulate formaldehyde generation. To further validate the hypothesis shown in Figure 1, efforts were devoted to search for homovanillin endgrouds, which resulted in a series of model compounds syntheses and verifications. There is also an indication of chain cleavage in Figure 1 if the resulting endgroups don't react, which should lead to the decrease of lignin glass transition temperature (Tg). By using dynamic mechanical analysis (DMA), we investigated the rheological properties of heat-treated wood with or without the presence of external acid including Tg, and Arrhenius activation energy (Ea) at glass transition. Meantime, we also focus on the properties of in situ lignin due to these treatments using wet chemistry methods, such as thioacidolysis and DFRC, combined with various analytical instrumentations, such as GC, GC/MS, NMR, UV-Vis, and Fluorometer. Lignin undergoes dramatic chain cleavage during heat treatment, while repolymerization or condensation reactions also occur simultaneously.
机译：在非结构木制复合材料的领域中，新的甲醛排放法规的严格性使得所有甲醛源，合成和生物的完全核算。我们的实验室的研究已经考虑了Lignin通过图1所示的假设反应途径对生物醛形成的贡献。它是已知的，并且我们进一步证明了，即共同的工业加热方法刺激甲醛产生和排放。木材基复合材料行业的影响很大;但也许未来的生物燃料行业也没有考虑过。广泛的木质素模型复合研究表明，两种酸解途径与其中一个产生甲醛。随着这些研究所建议的，酸类型会影响酸解途径，也许是由于酸反离子尺寸效应。鉴于此，我们将不同的酸应用于实木，并证明了它们操纵甲醛生成的能力。为了进一步验证图1所示的假设，致力于寻找HOMOVAlillin endgrouds的努力，这导致了一系列模型化合物合成和验证。如果所得的末组不会反应，还存在连锁裂解的指示，这应该导致木质素玻璃化转变温度（Tg）的降低。通过使用动态机械分析（DMA），我们研究了在玻璃化转变的外酸存在或不存在外部酸的情况下的热处理木材的流变性质，并在玻璃化转变下进行Arrhenius激活能量（EA）。同时，我们还专注于原位木质素的性质，由于这些处理使用湿化学方法，例如硫化物化学方法和DFRC，与各种分析仪器相结合，例如GC，GC / MS，NMR，UV-Vis和荧光计。木质素在热处理期间经历剧烈的链切割，而重新聚合或缩合反应也同时发生。

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