标题：Mechanistic insight into the self-coupling of 5-hydroxymethyl furfural to C-12 fuel intermediate catalyzed by ionic liquids
作者：Li, Jingjing; Wang, Binfen; Dou, Yefan; Yang, Yiying
作者机构：[Li, Jingjing; Wang, Binfen; Dou, Yefan] Shanxi Agr Univ, Coll Arts & Sci, Taigu 030801, Shanxi, Peoples R China.; [Yang, Yiying] Shandong Univ, Ins 更多
通讯作者：Li, JJ;Li, Jingjing
通讯作者地址：[Li, JJ]Shanxi Agr Univ, Coll Arts & Sci, Taigu 030801, Shanxi, Peoples R China.
摘要：DFT calculations have been carried out to obtain insight into the self-coupling of biomass-based 5-hydroxymethyl furfural (HMF) to C-12 fuel intermediate 5,5-dihydroxymethyl furoin (DHMF) catalyzed by ionic liquids (ILs). It was found that acetate-based IL or thiazolium IL in combination with the additive Et3N show high catalytic performance, wherein N-heterocyclic carbons (NHCs) derived from the cations of ILs act as the nucleophiles and the protonated acetate anion or the [Et3NH](+) acts as the proton shuttle. The effectiveness of this catalysis is attributed to the proton-shared three-center-four-electron (3c-4e) bonds between HMF and HOAc or [Et3NH](+), which stabilize the transition states and the intermediates. In addition, the results of the calculations also confirm that the nucleophilicity and basicity of NHCs are key factors for the self-coupling reaction. These results rationalize the experimental findings and offer valuable insights into understanding the catalysis of ILs.