The combination of 1‐butyl‐3‐methylimidazolium hydrogen sulfate ([Bmim]HSO₄) ionic liquid (IL) and microwave heating was used to esterify oleic acid as a green approach in biodiesel synthesis. To compare the heating systems, conventional heating and the ultrasonic method were employed but the microwave method was found to be more effective. H₂SO₄ and 1‐methyl imidazole hydrogen sulfate ([Hmim]HSO₄) were also used in the esterification of oleic acid and their catalytic activities were compared to that of [Bmim]HSO₄. ILs provided some advantages such as reusability, easy recyclability, and very stable activity. There was only a small decrease in the catalytic activity of [Bmim]HSO₄ after four successive applications, which means that ILs can be reused, contrary to homogeneous catalysts. The combination of IL catalysts and microwave irradiation proved to be a potential alternative method for biodiesel production.

中文翻译：

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离子液体催化剂的微波辅助油酸酯化反应

1-丁基-3-甲基咪唑硫酸氢盐（[Bmim] HSO ₄）离子液体（IL）和微波加热的组合被用作生物柴油合成中的绿色方法，以酯化油酸。为了比较加热系统，采用了常规加热和超声方法，但发现微波方法更为有效。H ₂ SO ₄和1-甲基咪唑硫酸氢盐（[Hmim] HSO ₄）也用于油酸的酯化反应，并与[Bmim] HSO ₄进行了催化活性比较。IL具有一些优势，例如可重复使用性，易于回收利用和非常稳定的活性。[Bmim] HSO ₄的催化活性仅小幅下降经过四次连续应用，这意味着IL可以重复使用，这与均相催化剂相反。IL催化剂和微波辐射的组合被证明是生物柴油生产的潜在替代方法。