高等学校化学学报

高等学校化学学报

• 研究论文 • 上一篇    下一篇

酸性离子液体H0的测定及盐效应的影响

王智远,董义,齐保辉,魏学洋,张佳辉,黄起中,李积升,高娜,邸士莹,胡玉峰   

  1. 中国石油大学（北京）化学工程与环境学院
  • 收稿日期:2024-12-09 修回日期:2025-01-15 出版日期:2025-01-18 发布日期:2025-01-18
  • 通讯作者: 胡玉峰 E-mail:huyf3581@sina.com
  • 基金资助:
    国家自然科学基金(批准号：22487418, 22078355)资助

Determination of Acidic Ionic Liquid H0 and the Influence of Salt Effect

WANG Zhiyuan, DONG Yi, QI Baohui, WEI Xueyang, ZHANG Jiahui, HUANG Qizhong, LI Jisheng, GAO Na, DI Shiying, Hu Yufeng   

  1. College of Chemical Engineering and Environment, China University of Petroleum (Beijing)
  • Received:2024-12-09 Revised:2025-01-15 Online:2025-01-18 Published:2025-01-18
  • Supported by:
    Supported by the National Natural Science Foundation of China (Nos. 22478418, 22078355)

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摘要： 离子液体的催化活性与其酸度的大小密不可分, 而Hammett酸度函数(H0)是一种表示酸度的最有效方法. 本文合成了一系列可用于三聚甲醛合成过程的吡咯烷酮类和咪唑类离子液体, 并对其在水溶液中的H0进行了系统的试验和理论研究, 比较了阴阳离子结构和溶剂的选择对酸度的影响规律. 研究了盐效应对1-丙基磺酸-3-甲基咪唑甲烷磺酸盐([C3SMIM][MSA])、甲烷磺酸、三氟甲烷磺酸和硫酸的H0的影响. 结果表明：阴离子对酸度的影响更为显著, 当阴离子相同时, 阳离子取代基的碳链越长, 酸度越强; 当阳离子相同时, 阴离子的电荷密度越小, 酸度越强; 对于同一类型的离子液体, 磺酸功能化的离子液体比未功能化的离子液体酸度要强. 大部分盐类起的是盐析效应, 对酸度起增强作用, 少数盐对酸度是减弱的, 如：对甲苯磺酸钠和1-丙基磺酸-3-甲基咪唑内盐(C3SMIM)等, 这些盐的共同特点是具有较大的离子尺寸, 电荷密度较低.

关键词: 离子液体, Hammett酸度函数, 盐效应, 三聚甲醛

Abstract: The catalytic activity of ionic liquids is closely related to their acidity, and the Hammett acidity function (H0) is the most effective way to represent acidity. This paper synthesized a series of pyrrolidinone based and imidazolium-based ionic liquids that can be used in the synthesis process of 1,3,5-trioxane, and conducted systematic experimental and theoretical studies on their H0 in aqueous solution. The influence of anionic and cationic structures and solvent selection on acidity were compared. The effect of salt effect on the H0 determination of 1-propylsulfonic-3-methylimidazolium methanesulfonate ([C3SMIM][MSA]), methanesulfonic acid, trifluoromethanesulfonic acid, and sulfuric acid was studied. The results indicate that anions have a more significant impact on acidity. When the anions are the same, the longer the carbon chain of the cation substituent, the stronger the acidity; When the cations are the same, the lower the charge density of the anions, the stronger the acidity; For the same type of ionic liquid, ionic liquids functionalized with sulfonic acid have stronger acidity than those that are not functionalized. Most salts have a salting out effect, which enhances acidity, while a few salts weaken acidity, such as sodium p-toluenesulfonate and 1-propylsulfonic-3-methylimidazolium salt (C3SMIM). The common characteristics of these salts are large ion size and low charge density.

Key words: Ionic liquids, Hammett acidity function, Salt effect; 1,3,5-Trioxane

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