Eco-friendly Pretreatment of Oil with High Free Fatty Acid Content Using a Sulfamic Acid/Ethanol System

In recent years, sulfamic acid (SA, NH₂SO₃H) has emerged as a novel green catalyst for organic synthesis because of several advantages, including its non‐volatility, non‐hygroscopicity, non‐corrosivity, and low cost. This work reports the use of sulfamic acid as a catalyst in the pretreatment of oil with a high content of free fatty acids (10 and 20 % FFA) in ethanol or methanol. The process (esterification reaction) used in the pretreatment of the oil was carried out under a variety of conditions, initial fatty acid content, temperature, type of alcohol, and % catalyst. The experiments using an NH₂SO₃H/ethanol system resulted in a high fatty acid ethyl ester conversion, 88.53 % (±0.95) from an initial acidity of 40 mg KOH/g (20 % FFA), using 8 % NH₂SO₃H as the catalyst. According to the results, the methodology using sulfamic acid and ethanol demonstrated elevated potential for a environmentally‐friendly means of biodiesel production.