Optimizing the Process Conditions of Corn Oil Methyl Ester for Bioresin Production

Abstract The conversion of corn oil into quality methyl ester through the transesterification process is an age-old concept. Because of its higher degree of unsaturation, similar to soybean oil, transesterified corn oil has promising properties to produce bio-based resin. Replicating published methods did not result in desired quantity and quality of corn methyl ester needed for bio-resin production, which requires further investigation. This research investigated the effect of different reaction conditions on the yield and quality of methyl ester produced from corn oil. The reaction was conducted at 60°C with a methanol-oil ratio of 6:1 and NaOH as a catalyst. Hypothesized recovered yield (> 70%) of corn methyl ester was achieved after stopping the reaction with HCl. The process was conducted at different reaction times (0.5, 1, and 1.5 h) and acid amounts (0, 1.3, 2.6, 3.9, and 5.2 mL). The methyl ester yield ranged from 45–79%. A statistical model was obtained with linear and quadratic terms, and the recovered yield varied significantly with the acid amount, reaction time, and their interactions. The addition of 2.6 mL acid after the transesterification process resulted in a 15–25% increased yield compared to no acid treatment. On the other hand, the yield was reduced 18–24% with increasing time when no acid was added. All the measured characteristics of the produced corn methyl ester sample were found within the limits of ASTM D6751 pure methyl ester. Overall, the optimization of the transesterification process showed promise in increasing the yield of quality methyl ester from corn oil.