Abstract Fractionation of crude bio-oil into an organic phase and an aqueous phase by simply adding water and research strategies targeted at producing hydrogen, fuels, or other value-added chemicals from the fractions have been proposed. However, the stability of the bio-oil fractions has not been comprehensively investigated. The objective of this study was to comparatively investigate the stability of crude bio-oil and its two fractions by evaluating their physicochemical properties during long-term storage at room temperature and accelerated aging at 40 °C and 60 °C. Comparing with crude bio-oil, the resulted aqueous phase is more stable; for the organic phase, the stability is also improved in terms of the changes in viscosity and average molecular weight, but not in terms of the increasing water content and total acid number. In overview for all the crude bio-oil and its two fractions, the water content, viscosity, total acid number, and average molecular weight increased with the increase of aging time and temperature; except for acetic acid and propionic acid, which slightly increased in content at all aging conditions, all the other 13 measured chemical contents decreased with the increasing aging time and temperature, indicating that the aging process involved all the six chemical groups of anhydrosugars, carboxylic acids, alcohols, furans, ketones, and phenolics, accelerated at higher temperature.

中文翻译：

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粗生物油及其水提馏分的稳定性

摘要 通过简单地加水将粗生物油分馏成有机相和水相，并提出了旨在从馏分中生产氢气、燃料或其他增值化学品的研究策略。然而，生物油馏分的稳定性尚未得到全面研究。本研究的目的是通过评估其在室温下长期储存和在 40 °C 和 60 °C 下加速老化过程中的理化性质，比较研究粗生物油及其两种馏分的稳定性。与粗生物油相比，所得水相更稳定；对于有机相，稳定性在粘度和平均分子量的变化方面也有所提高，但在含水量和总酸值的增加方面没有提高。综观所有粗生物油及其两个馏分，含水量、粘度、总酸值和平均分子量随着老化时间和温度的增加而增加；除乙酸和丙酸在所有老化条件下含量略有增加外，其余 13 种化学成分均随老化时间和温度的增加而降低，表明老化过程涉及脱水糖、羧酸这 6 个化学基团。 、醇类、呋喃类、酮类和酚类，在较高温度下加速。