Biodiesel is subject to radical reactions that promote degradation. To decrease the speed of these degradation reactions and increase oxidative stability, either natural or synthetic antioxidants are added to biodiesel. Thus, the objective of this study is to evaluate the effect of extracts of pecan nutshell (Carya illinoensis) as natural antioxidants derived from biomass using water, ethanol, and methanol/water (50/50) as a solvent for extraction. The addition of these antioxidants is performed during the soybean biodiesel washing process in an unconventional manner. The results obtained are statistically analyzed and compared to the control. The induction time (IT) for the biodiesel samples washed with ethanolic extract of pecan nutshell (5 g L⁻¹), aqueous extract of pecan nutshell (12 g L⁻¹) and methanol/water extract of pecan nutshell (12 g L⁻¹), are, respectively, 9.46, 7.60, 7.43 h. The activation energy and the storage time of the biodiesel samples washed with the extracts are also studied. The order of reaction of the oxidation kinetics of biodiesel is first order.

中文翻译：

---

大豆生物柴油 B100 中山核桃壳 (Carya illinoensis) 提取物的抗氧化评价。

生物柴油会发生促进降解的自由基反应。为了降低这些降解反应的速度并提高氧化稳定性，生物柴油中添加了天然或合成的抗氧化剂。因此，本研究的目的是评估山核桃壳（Carya illinoensis）提取物作为源自生物质的天然抗氧化剂的效果，使用水、乙醇和甲醇/水（50/50）作为提取溶剂。这些抗氧化剂的添加是在大豆生物柴油洗涤过程中以非常规方式进行的。对所得结果进行统计分析并与对照进行比较。用山核桃壳乙醇提取物（5 g L ^-1）、山核桃壳水提取物（12 g L ^-1）和山核桃壳甲醇/水提取物（12 g L -1 ）洗涤的生物柴油样品的诱导时间（IT ^{） 1} )分别为9.46、7.60、7.43小时。还研究了用提取物洗涤的生物柴油样品的活化能和储存时间。生物柴油的氧化动力学的反应级数为一级。