Department of Chemical Engineering, Universiti Teknologi PETRONAS, 32610 Seri Iskandar, Perak, Malaysia; Centre of Research in Ionic Liquid (CORIL), Universiti Teknologi PETRONAS, 32610 Seri Iskandar, Perak, Malaysia.
Centre of Research in Ionic Liquid (CORIL), Universiti Teknologi PETRONAS, 32610 Seri Iskandar, Perak, Malaysia.
Ultrason Sonochem. 2020 Jan;60:104732. doi: 10.1016/j.ultsonch.2019.104732. Epub 2019 Aug 14.
Biodiesel production via esterification/transesterification reactions can be catalyzed by homogenous or heterogeneous catalysts. Development of heterogeneous catalysts for biodiesel production is highly advantageous due to the ease of product purification and of catalyst recyclability. In this current work, a novel acidic [DABCODBS][CFSO] dicationic ionic liquid (DIL) was used as heterogeneous catalyst to produce biodiesel using oleic acid as model oil. The esterification was conducted under ultrasonic irradiation (20 kHz) using a 14 mm ultrasonic horn transducer operated at various duty cycles. It was observed that the duty cycle, amplitude, methanol to oil molar ratio, catalyst amount and reaction temperature were the major factors that greatly impact the necessary reaction time to lead to a high yield of biodiesel. The reaction conditions were optimized with the aid of Response Surface Methodology (RSM) designed according to the Quadratic model of the Box Behnken method. The optimum conditions were found to be at catalyst amount of 0.64 mol%, methanol to oil ratio of 14.3:1, temperature of 59 °C, reaction time of 83 min and amplitude of 60% in continuous mode. The results showed that the oleic acid was successfully converted into esters with conversion value of 93.20% together with significant reduction of reaction time from 7 h (using mechanical stirring) to 83 min (using ultrasonication). The results also showed that the acidic DIL catalyst we designed purposely was efficient to catalyze the ultrasonic-assisted esterification yielding high conversion of oleic acid to methyl oleate on short times. The DIL was also recycled and reused for at least five times without significant reduction in performance. Overall, the procedureoffersadvantages including short reaction time, good yield, operational simplicity and environmentally benign characteristics.
生物柴油可以通过酯化/酯交换反应来生产，该反应可以使用均相或多相催化剂来催化。由于产物易于纯化以及催化剂可重复使用，因此开发用于生物柴油生产的多相催化剂具有很大的优势。在当前这项工作中，使用新型酸性[DABCODBS][CFSO]二阳离子离子液体（DIL）作为多相催化剂，以油酸为模型油生产生物柴油。酯化反应在超声波辐射（20 kHz）下进行，使用 14 mm 超声变幅杆换能器，在不同的占空比下操作。结果表明，占空比、振幅、甲醇与油的摩尔比、催化剂用量和反应温度是极大影响达到高生物柴油产率所需反应时间的主要因素。借助响应面法（RSM），根据 Box-Behnken 方法的二次模型设计了反应条件优化。最佳条件为催化剂用量为 0.64 mol%，甲醇与油的摩尔比为 14.3:1，温度为 59°C，反应时间为 83 min，连续模式下的振幅为 60%。结果表明，油酸成功地转化为酯，转化率为 93.20%，同时将反应时间从 7 小时（使用机械搅拌）显著缩短至 83 分钟（使用超声波）。结果还表明，我们专门设计的酸性 DIL 催化剂在超声辅助酯化中效率很高，可在短时间内将油酸高转化率转化为油酸甲酯。DIL 还可以回收并重复使用至少 5 次，性能没有明显下降。总的来说，该工艺具有反应时间短、产率高、操作简单和环境友好等优点。
