Sulfonated imidazolium ionic liquid-catalyzed transesterification for biodiesel synthesis

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• 作者：Pei Fan^a ; ^b ; ^c ; ^d ; Shiyou Xing^a ; ^b ; ^c ; ^d ; Jiayan Wang^a ; ^f ; Junying Fu^a ; ^b ; ^d ; Lingmei Yang^a ; ^b ; ^d ; Gaixiu Yang^a ; ^b ; ^d ; Changlin Miao^a ; ^b ; ^d ; ^{miaocl@ms.giec.ac.cn" class="auth_mail" title="E-mail the corresponding author} ; Pengmei Lv^a ; ^b ; ^d ; ^e ; ^{lvpm@ms.giec.ac.cn" class="auth_mail" title="E-mail the corresponding author}
• 关键词：Ionic liquid ; Biodiesel ; Transesterification ; Sulfonate
• 刊名：Fuel
• 出版年：2017
• 出版时间：15 January 2017
• 年：2017
• 卷：188
• 期：Complete
• 页码：483-488
• 全文大小：639 K

文摘

Four kinds of imidazolium ionic liquids (ILs) were employed to catalyze the transesterification reaction of rapeseed oil. The effects of molar ratio of methanol to rapeseed oil, catalyst dosage, reaction temperature, and reaction time, and the deactivation of water on catalytic activity were explored. The results showed that imidazolium ILs with long alkyl chains and sulfonated groups exhibited the best catalytic activities due to their strong Brønsted acidity. The catalytic activity was depend on the $\text{<glyph name="sbnd"></glyph>}$SO₃H group in the cation, not the anion HSO₄⁻. Water molecules competed with the anion to bind with the protons of the imidazolium cation. This results in the disruption of the structure of ILs, leading to deactivation; increasing the reaction temperature could alleviate this negative effect of water. The yield of fatty acid methyl ester (FAME) remained constant (∼85%) at 130 °C, when the water content increased from 1 wt% to 5 wt%. The highest yield of FAME for the catalyst 1-butylsulfonate-3-methyl imidazolium hydrogen sulfate ([BSO₃HMIM][HSO₄]) could reach 100% under optimum conditions.