Methyl ester production in microchannel using a new grafted basic ionic liquid as the nanocatalyst

Microchannel increases the rapidity of mixing and mass transfer in chemical reactions so the production rate enhances. In this investigation, a new basic ionic liquid pyridine base was stabilized on the solid base, afterward was utilized for the methyl esters production in microchannel. The major nominal variables to optimize the conditions for achieving a maximum yield of biodiesel were: catalyst concentration, methanol-to-oil molar ratio and reaction time (injection time) and microchannel type (M 1 , M 2 and M 3 ) as categorical factor. Using response surface methodology (Box–Behnken design), experiments were designed. By evaluating the outcomes, the optimum point was earned. The ideal conditions according to the empirical model were: methanol/oil molar ratio = 10.9, reaction time = 1.74 min (residence time = 1.16 s), catalyst dosage (% wt.) = 3.49 and M 1 microchannel type. The model's prediction for the produced methyl ester yield at optimum conditions was 97%. The experimental result of 95.2% for the optimum condition indicated excellent accuracy of the model. The catalyst was reused six times at the best condition. With great results, it ultimately yielded 88.3% at the sixth run, which shows the significant strength of the catalyst. Moreover, controlled by the optimal conditions for M 1 microchannel, the synthesized ionic liquid was used. Accompanied by the same weight percent added to the oil, with three repetitions and average biodiesel yield of 98.85% was gained. It should also be mentioned that under best conditions, the employment of selected M 1 microchannel instead of the straight tube increased the pressure drop by up to 3.6 times. Graphic abstract