Abstract

Environmental concerns caused by the constant use of fossil fuels can be solved by the use of biofuels. This work shows the application of the oil of Trichilia emetica Vahl (Mafura) seeds originating from Mozambique as a feedstock for biodiesel production. The high oil acidity required a two-step reaction involving esterification using sulphuric acid (H₂SO₄) as catalyst followed by for the conversion of Mafura oil to fatty acid methyl ester (FAME). The acid value was reduced from 27.58 to 0.36 (mg KOH g⁻¹). Other physicochemical properties (moisture content, density, free glycerol) of FAME attended the established limits of EN14214 and Brazilian norms. The low induction-period (IP) was surpassed after the addition of 500 ppm of the synthetic antioxidant tert-butylhydroquinone (TBHQ) resulting in 10.8 h. The conversion of the feedstock (99.1%wt) was confirmed by gas chromatograph with flame ionization detector (GC-FID). The fatty-acid methyl ester contents of the Mafura biodiesel presented palmitic acid (39.32%wt), linoleic acid (31.09%wt), oleic acid (25.77%wt), stearic acid (2.29%wt), meristic acid (0.78%wt), linolenic acid (0.61%wt) and lauric acid (0.14%wt). These results show that the biodiesel produced from Mafura oil met most of the quality standards required by American, Brazilian and European regulatory agencies.

摘要

由持续使用化石燃料引起的环境问题可以通过使用生物燃料来解决。这项工作展示了将源自莫桑比克的吐毛树 ( Trichilia emetica Vahl) (Mafura) 种子油作为生物柴油生产原料的应用。高油酸度需要两步反应，包括使用硫酸 (H ₂ SO ₄ ) 作为催化剂进行酯化，然后将 Mafura 油转化为脂肪酸甲酯 (FAME)。酸值从 27.58 降低到 0.36 (mg KOH g ^-1）。FAME 的其他物理化学性质（水分含量、密度、游离甘油）符合 EN14214 和巴西标准的既定限制。在添加 500 ppm 的合成抗氧化剂叔丁基对苯二酚 (TBHQ) 后超过低诱导期 (IP)，导致 10.8 小时。通过带有火焰离子化检测器 (GC-FID) 的气相色谱仪确认原料 (99.1%wt) 的转化率。Mafura生物柴油的脂肪酸甲酯含量表现为棕榈酸（39.32%wt）、亚油酸（31.09%wt）、油酸（25.77%wt）、硬脂酸（2.29%wt）、分叉酸（0.78%wt） )、亚麻酸 (0.61%wt) 和月桂酸 (0.14%wt)。这些结果表明，由 Mafura 油生产的生物柴油符合美国、巴西和欧洲监管机构要求的大部分质量标准。