双咪唑磺酸型离子液体催化煎炸废弃油制备生物柴油

Preparation of biodiesel from fried waste oil catalyzed by bisimidazole sulfonic acid type ionic liquid

为高效环保地制备生物柴油,通过三步法合成了一系列HSO_(4)HSO_(3)-C_(3)[MIM]C_(n)[MIM]C_(3)-HSO_(3)HSO_(4)(简写为C_(n)MSS,n=2~6)双咪唑磺酸型离子液体,对其催化酯交换反应的性能进行了探究,并对离子活性最强的离子液体进行了核磁共振表征。以该离子液体为催化剂,通过单因素实验对三油酸甘油酯模型反应条件进行优化,并在此基础上采用正交实验优化煎炸废弃油制备生物柴油的工艺条件,同时对生物柴油产品进行了红外光谱和核磁共振表征。结果表明:离子液体C_(5)MSS的催化性能最强;在醇油摩尔比18∶1、反应时间8 h、反应温度100℃、催化剂用量8%(以三油酸甘油酯质量计)条件下,油酸甲酯产率为91.18%,且该离子液体重复使用7次油酸甲酯产率仍然能够达到83%以上。煎炸废弃油制备生物柴油的最优工艺条件为醇油摩尔比18∶1、反应温度80℃、反应时间9 h、催化剂用量10%(以煎炸废弃油质量计),在此条件下生物柴油的产率可达98.60%。红外光谱和核磁共振表征结果表明反应生成了脂肪酸甲酯,且酯交换反应比较彻底。

In order to prepare biodiesel efficiently and environmentally,a series of HSO_(4)HSO_(3)-C_(3)[MIM]C_(n)[MIM]C_(3)-HSO_(3)HSO_(4)(abbreviated as C_(n)MSS,n=2-6)bisimidazole sulfonic acid type ionic liquids were synthesized by a three-step method,and the catalytic performance on the transesterification reaction was explored.The ionic liquids with the strongest ionic activity were characterized by nuclear magnetic resonance.With the ionic liquid as catalyst,the reaction conditions of triolein model were optimized by single factor experiment,and on this basis,the process conditions for preparing biodiesel from fried waste oil were optimized by orthogonal experiment.The biodiesel was characterized by infrared spectroscopy and nuclear magnetic resonance.The results showed that C_(5)MSS showed the strongest catalytic performance.Under the conditions of molar ratio of methanol to oil 18∶1,reaction time 8 h,reaction temperature 100℃,and ionic liquid dosage 8%(based on the triolein mass),the yield of methyl oleate was 91.18%,and the yield of methyl oleate could still reach more than 83% after the ionic liquid was reused for seven times.The optimal process conditions for preparing biodiesel from fried waste oil were obtained as follows:molar ratio of methanol to oil 18∶1,reaction temperature 80℃,reaction time 9 h,and catalyst dosage 10%(based on the mass of fried waste oil).Under these conditions,the yield of biodiesel could reach 98.60%.The characterization results of infrared spectroscopy and nuclear magnetic resonance showed that fatty acid methyl esters were produced by the reaction,and the transesterification reaction was relatively thorough.