Fonts Isabel, Lázaro Cristina, Cornejo Alfonso, Sánchez José Luis, Afailal Zainab, Gil-Lalaguna Noemí, Arauzo Jesús María
Aragon Institute for Engineering Research (I3A), Thermochemical Processes Group (GPT), University of Zaragoza, 50018 Zaragoza, Spain.
Institute for Advanced Materials and Mathematics (INAMAT) - Department of Sciences, Public University of Navarra, 31006 Pamplona, Spain.
Energy Fuels. 2024 Sep 25;38(19):18688-18704. doi: 10.1021/acs.energyfuels.4c02641. eCollection 2024 Oct 3.
Bio-oil obtained from biomass pyrolysis has great potential for several applications after being upgraded and refined. This study established a method for separating bio-oil into different fractions based on polarity and molecular size to extract phenolic and polyphenolic compounds with antioxidant properties. The fractions were analyzed using various spectroscopic and chromatographic techniques, such as GC/MS, FTIR, UV-vis, SEC, DOSY-NMR, C-NMR, and P-NMR. The antioxidant properties of these fractions were tested by examining their ability to improve the oxidative stability of biodiesel. The results strongly connected the bio-oil's chemical functionalities and antioxidant power. During solvent fractionation, dichloromethane could extract phenolic structures, which were subsequently size-fractionated. The subfractions with lower molecular weight (in the order of monomers and dimers) outperformed the antioxidant potential of the crude bio-oil. Heavier subfractions from dichloromethane extraction did not show good antioxidant abilities, which was related to the low hydroxy group content. After solvent extraction, phenolic oligomers remained in the water-insoluble/dichloromethane-insoluble fraction, which showed good antioxidant potential despite its low solubility in biodiesel.
通过生物质热解获得的生物油在经过提质和精炼后具有多种应用的巨大潜力。本研究建立了一种基于极性和分子大小将生物油分离成不同馏分的方法，以提取具有抗氧化性能的酚类和多酚类化合物。使用各种光谱和色谱技术对馏分进行分析，如气相色谱/质谱联用仪（GC/MS）、傅里叶变换红外光谱仪（FTIR）、紫外可见光谱仪（UV-vis）、尺寸排阻色谱（SEC）、扩散排序核磁共振谱（DOSY-NMR）、碳核磁共振谱（C-NMR）和磷核磁共振谱（P-NMR）。通过检测这些馏分提高生物柴油氧化稳定性的能力来测试其抗氧化性能。结果有力地将生物油的化学官能团与抗氧化能力联系起来。在溶剂分级分离过程中，二氯甲烷可以提取酚类结构，随后对其进行尺寸分级。较低分子量的亚馏分（以单体和二聚体的顺序）的抗氧化潜力优于粗生物油。二氯甲烷萃取得到的较重亚馏分没有显示出良好的抗氧化能力，这与低羟基含量有关。溶剂萃取后，酚类低聚物保留在水不溶性/二氯甲烷不溶性馏分中，尽管其在生物柴油中的溶解度较低，但仍显示出良好的抗氧化潜力。
