Patle Dipesh S, Sharma Swapnil, Gadhamsetti Akhil Premkumar, Balinge Kamlesh Rudreshwar, Bhagat Pundlik Rambhau, Pandit Sanket, Kumar Sushil
Chemical Engineering Department, Motilal Nehru National Institute of Technology, Allahabad 211004, Uttar Pradesh, India.
Chemical Engineering Department, School of Civil and Chemical Engineering and Department of Chemistry, School of Advanced Sciences, VIT Vellore, Vellore 632014, Tamil Nadu, India.
ACS Omega. 2018 Nov 14;3(11):15455-15463. doi: 10.1021/acsomega.8b02021. eCollection 2018 Nov 30.
In this investigation, we report the synthesis of biodiesel using benzimidazolium-based brønsted acid ionic liquid (BBAIL) catalyst under the influence of ultrasonication. The prepared BBAIL catalyst was characterized by Fourier transform infrared and NMR spectroscopy techniques, and its acidity was determined by the Hammett method with 4-nitroaniline as the indicator. Ultrasonicator horn (22 kHz, 500 W) was used in this work with an on-off cycle of 50-20 s at 70% amplitude. The highest biodiesel yield of 96% was achieved by ultrasonication when 1:10 molar ratio of castor oil to methyl alcohol was used at 50 °C temperature with 9 mol % of the catalyst in just 90 min, which is about 10 times lesser than the process without ultrasonication. At similar conditions, 96% biodiesel yield was obtained in 14 h without ultrasonication. In summary, ultrasonication proved to be an efficient way to improve biodiesel synthesis in less time and BBAIL showed excellent activity toward the conversion of glycerides to synthesize biodiesel. Other important highlights are easy separation of the catalyst and recyclability up to three cycles with small decrease in its activity.
在本研究中，我们报道了在超声作用下使用基于苯并咪唑鎓的布朗斯特酸性离子液体（BBAIL）催化剂合成生物柴油的过程。通过傅里叶变换红外光谱和核磁共振光谱技术对制备的BBAIL催化剂进行了表征，并以4-硝基苯胺为指示剂，采用哈米特方法测定了其酸度。本工作中使用了超声换能器喇叭（22 kHz，500 W），在70%振幅下以50 - 20 s的开-关循环运行。在50℃温度下，当蓖麻油与甲醇的摩尔比为1:10且使用9 mol%的催化剂时，仅在90分钟内通过超声处理获得了高达96%的最高生物柴油产率，这比无超声处理的过程所需时间少约10倍。在类似条件下，无超声处理时在14小时内获得了96%的生物柴油产率。总之，超声处理被证明是一种在更短时间内提高生物柴油合成效率的有效方法，并且BBAIL对甘油酯转化合成生物柴油表现出优异的活性。其他重要亮点包括催化剂易于分离且可循环使用多达三个循环，其活性仅有小幅下降。
