Аннотация
ABSTRACT Cottonseed oil‐based biodiesel is a renewable alternative to conventional diesel fuel. The experiments were conducted at molar ratios (3:1–9:1), reaction times (30–120 min), and reaction temperatures (40–70°C). At a 5:1 molar ratio, reaction conditions of 1% NaOH, 60°C, and 90 min gave the highest biodiesel yield (93%), but increasing the NaOH loading also decreased the yield due to soap formation, whereas higher molar ratios depressed the biodiesel yield. Cottonseed methyl ester (CSME) contained 77.5%, 11.8%, and 10.61% carbon, hydrogen, and oxygen, respectively, by elemental analysis, whereas petroleum diesel contained 86.39%, 13.0%, and 0.5%, respectively. The measured fuel properties fall within both ASTM D6751 and EN 14214 biodiesel specification limits at constant loads. Brake thermal efficiencies were found to be 30.99% for diesel, 28.99% for CSME10, and 27.98% for CSME20. So, it was proved that a slight reduction (unaffected) in fuel efficiency occurred when using a bio‐cottonseed diesel blend.