Interest in biodiesel research has escalated over the years due to dwindling fossil fuel reserves. The implementation of a carbon-based solid acid catalyst in biodiesel production eradicates the separation problems associated with homogeneous catalysis. However, its application in the glycerol-free interesterification process for biodiesel production is still rarely being studied in the literature. In this study, novel environmentally benign catalysts were prepared from oil palm empty fruit bunch (OPEFB) derived activated carbon (AC) which is sustainable and low cost via direct sulfonation using concentrated sulfuric acid. The effects of synthesizing variables such as carbonization and sulfonation temperatures with different holding times towards the fatty acid methyl ester (FAME) yield in interesterification reaction with oleic acid and methyl acetate were investigated in detail. It was found that the optimum carbonization temperature and duration together with sulfonation temperature and duration were 600 °C, 3 h, 100 °C and 6 h, respectively. The catalyst possessed an amorphous structure with a high total acid density of 9.0 mmol NaOH g-1 due to the well-developed porous framework structure of the carbon support. Under these optimum conditions, the OPEFB derived solid acid catalyst recorded an excellent catalytic activity of 50.5% methyl oleate yield at 100 °C after 8 h with 50:1 methyl acetate to oleic acid molar ratio and 10 wt% catalyst dosage. The heterogeneous acid catalyst derived from OPEFB had shown promising properties that made them highly suitable for cost-effective and environmental-friendly glycerol-free biodiesel production.

中文翻译：

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从油棕空果束中合成可再生的非均相酸催化剂，用于生产无甘油的生物柴油。

由于化石燃料储备的减少，多年来对生物柴油研究的兴趣不断增加。在生物柴油生产中碳基固体酸催化剂的实施消除了与均相催化相关的分离问题。然而，其在用于生产生物柴油的无甘油酯交换工艺中的应用仍很少在文献中进行研究。在这项研究中，从油棕空果束（OPEFB）衍生的活性炭（AC）制备了新型的环境友好型催化剂，该活性炭通过使用浓硫酸的直接磺化反应可持续且成本低廉。详细研究了在不同的保持时间下，碳化和磺化温度等合成变量对油酸和乙酸甲酯酯交换反应中脂肪酸甲酯（FAME）收率的影响。发现最佳碳化温度和持续时间以及磺化温度和持续时间分别为600℃，3h，100℃和6h。由于碳载体的多孔框架结构发达，该催化剂具有无定形结构，其总酸密度高，为9.0 mmol NaOH g-1。在这些最佳条件下，衍生自OPEFB的固体酸催化剂在8 h后以50：1的乙酸甲酯与油酸的摩尔比和10 wt％的催化剂用量记录了出色的催化活性，在100°C时油酸甲酯的收率为50.5％。