Page 148 - 《精细化工》2021年第5期

第 38 卷第 5 期 精 细 化 工 Vol.38, No.5
202 1 年 5 月 FINE CHEMICALS May 2021

催化与分离提纯技术
咪唑类离子液体催化合成正龙脑

*
黄金艳，杨文娟，蒋丽红 ，王亚明，郑燕娥，黄鹏鹏
（昆明理工大学 化学工程学院，云南 昆明 650500）

13
1
摘要：通过两步法合成了 4 种阴离子不同的咪唑类离子液体，采用 FTIR、 HNMR、 CNMR、TG、Hammett
酸度函数对其结构和酸度进行表征。以 α-蒎烯酯化-皂化反应为探针反应，考察了 4 种离子液体对正龙脑的选择

性。结果表明，阴离子为 HSO 4 的离子液体对正龙脑的选择性最好，与 Hammett 酸度函数计算结果吻合。选取
[Bmim-SO 3 H]HSO 4 做进一步的工艺优化，得到的优化工艺条件为：环己烷用量 35 mL，反应温度为 120 ℃，离
子液体为松节油质量(10 g)的 8%，n(α-蒎烯)∶n(乙酸)=1∶3，反应时间 8 h。在该条件下，α-蒎烯的转化率为 100%，
–
+
正龙脑选择性为 39.83%，且占总龙脑的 92.56%。离子液体提供的 H 使 α-蒎烯质子化形成碳正离子，HSO 4 稳定
非经典碳正离子，与乙酸根形成络合物，使生成正龙脑的反应更容易发生。[Bmim-SO 3 H]HSO 4 重复使用 3 次仍
具有较高的活性，α-蒎烯的转化率仍达 99.76%，正龙脑的选择性为 35.45%。
关键词：α-蒎烯；咪唑类离子液体；酯化-皂化；正龙脑；碳正离子；催化技术
中图分类号：TQ426; TQ223.1 文献标识码：A 文章编号：1003-5214 (2021) 05-1002-08

Catalytic synthesis of n-borneol by imidazole ionic liquid

*
HUANG Jinyan, YANG Wenjuan, JIANG Lihong , WANG Yaming,
ZHENG Yan'e, HUANG Pengpeng
（Faculty of Chemical Engineering, Kunming University of Science and Technology, Kunming 650500, Yunnan, China）

Abstract: Four imidazole ionic liquids with different anions were synthesized by a two-step method. The
1
13
structure and acidity of ionic liquids were characterized by FTIR, HNMR, CNMR, TG, Hammett acidity
function. The selectivity of four ionic liquids to n-borneol was investigated by using esterification-
saponification reaction of α-pinene as a probe reaction. The result showed that the ionic liquid with an anion
–
of HSO 4 had the best selectivity to n-borneol, which was consistent with the result that was calculated by
Hammett's acidity function. The preparation process of n-borneol using [Bmim-SO 3H]HSO 4 as catalyst was
optimized. The optimized process conditions were obtained as follows: cyclohexane of 35 mL, reaction
temperature of 120 ℃, ionic liquid being 8% of the mass (10 g) of turpentine, n(α-pinene)∶n(acetic
acid)=1∶3, reaction time of 8 h. Under these conditions, the conversion rate of α-pinene was 100%, and
+
the selectivity of n-borneol was 39.83%, accounting for 92.56% of the total borneol. H provide by the ionic

liquid protonated α-pinene to form carbocation, HSO 4 stabilized non-classical carbocation and formed a
complex with acetate, which made the reaction of n-borneol more likely to occur. [Bmim-SO 3H]HSO 4 still
had high activity after repeated use for three times, the conversion rate of α-pinene and the selectivity of
n-borneol were still 99.76% and 35.45%.
Key words: α-pinene; imidazole ionic liquids; esterification-saponification; n-borneol; carbocation;
catalysis technology

龙脑又名冰片，有正龙脑和异龙脑之分，在医 天然龙脑价格昂贵，在自然界中含量较少，人工合
[1]
[2]
药 、香精香料、化妆品行业 等具有广泛的应用。 成龙脑是必然趋势。与异龙脑相比，正龙脑具有副

收稿日期：2020-10-21; 定用日期：2021-01-25; DOI: 10.13550/j.jxhg.20200960
基金项目：国家自然科学基金（21266012）；国家自然科学基金联合重点支持项目（U1202265）
作者简介：黄金艳（1994—），女，硕士生，E-mail：517960911@qq.com。联系人：蒋丽红（1968—），女，教授，E-mail：jlh65@163.com。