合成了4种不同阳离子的-SO3H功能化对甲苯磺酸季铵盐离子液体，并用FT-IR和NMR表征结构，结果表明，合成的离子液体符合其理论结构特征。热重分析实验表明离子液体的分解温度都在200℃以上，可以作为合成生物柴油的催化剂；采用吡啶红外探针法测定其酸性大小，实验结果表明其酸性受阳离子烷基侧链影响，烷基侧链越短或越少，酸性越强，但相差不大。以它们为催化剂进行了三油酸甘油酯酯交换反应制备生物柴油的研究，实验表明，这些-SO3H 功能化对甲苯磺酸季铵盐离子液体的催化活性都较高，油酸甲酯的产率与离子液体的酸性顺序一致，正-丙基磺酸-三乙基对甲苯磺酸铵的催化活性最高。考察了正-丙基磺酸-三乙基对甲苯磺酸铵离子液体用量、醇油摩尔比、反应时间、反应温度对生物柴油产率的影响规律。实验结果表明，在甲醇、油脂和离子液体的摩尔比为12：1：0.167，反应温度130℃下反应4 h，油酸甲酯的产率可达到92.16%；将反应后离子液体相中的甲醇蒸出，再用乙酸乙酯将其中的甘油萃取出来，剩余的离子液体直接用于下次的酯交换反应，油酸甲酯的产率无明显降低，表明离子液体的稳定性好，回收的离子液体可循环使用。%Alkane sulfonic acid functionalized p-toluene sulfonic acid ionic liquids with four different cations of quaternary ammonium were synthesized. Their IR and NMR spectra show that their structures are in accordance with their theoritical structure. The TG curves show that they are stable and their decomposition temperatures are above 200℃, therefore they can be used as catalyst for the synthesis of biodiesel. Their acidities were determined by using IR spectroscopic probe with pyridine, the results show that the less or shorter the carbon chain in their cations, the stronger the acidity of the ionic liquid, but the difference is little. Meanwhile, the ionic liquids were used as catalyst to prepare biodiesel from glycerol trioleate, and it was found that the yield of methyl oleate is in the same sequence as the acidity of the ionic liquids, and the n-propyl sulfonic acid-3(ethyl) p-toluene sulfonate ionic liquid plays the best. Effects of ionic liquids dosage, mole ratio of methanol to glycerol trioleate, reaction time and reaction temperature on the yield of methyl oleate were investigated. Under optimal transesterification conditions, n (methanol):n (glycerol trioleate):n ( ionic liquids) =12:1:0.167, reaction time 4 h and temperature 130℃, the yield of methyl oleate could reach 92.16%. After the methanol was evaporated and the glycerol was extracted from the ionic liquid phase with acetic ester, the remainder of the ionic liquid phase was reused directly in the next biodiesel preparing reaction, the results show that the yield of methyl oleate is no reduced obviously, which indicates that Alkane sulfonic acid functionalized p-toluene sulfonic acid ionic liquids with four different cations of quaternary ammonium were synthesized. Their IR and NMR spectra show that their structures are in accordance with their theoritical structure. The TG curves show that they are stable and their decomposition temperatures are above 200℃, therefore they can be used as catalyst for the synthesis of biodiesel. Their acidities were determined by using IR spectroscopic probe with pyridine, the results show that the less or shorter the carbon chain in their cations, the stronger the acidity of the ionic liquid, but the difference is little. Meanwhile, the ionic liquids were used as catalyst to prepare biodiesel from glycerol trioleate, and it was found that the yield of methyl oleate is in the same sequence as the acidity of the ionic liquids, and the n-propyl sulfonic acid-3(ethyl) p-toluene sulfonate ionic liquid plays the best. Effects of ionic liquids dosage, mole ratio of methanol to glycerol trioleate, reaction time and reaction temperature on the yield of methyl oleate were investigated. Under optimal transesterification conditions, n (methanol):n (glycerol trioleate):n ( ionic liquids) =12:1:0.167, reaction time 4 h and temperature 130℃, the yield of methyl oleate could reach 92.16%. After the methanol was evaporated and the glycerol was extracted from the ionic liquid phase with acetic ester, the remainder of the ionic liquid phase was reused directly in the next biodiesel preparing reaction, the results show that the yield of methyl oleate is no reduced obviously, which indicates that the ionic liquids were stable, and could be recoveried and reused.
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