Organocatalytic Upgrading of Furfural and 5-Hydroxymethyl Furfural to C₁₀ and C₁₂ Furoins with Quantitative Yield and Atom-Efficiency [electronic resource]

• Ngôn ngữ: eng
• Ký hiệu phân loại: 660.6 Biotechnology
• Thông tin xuất bản: Washington, D.C. : Oak Ridge, Tenn. : United States. Dept. of Energy. Office of Science ; Distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy, 2015
• Mô tả vật lý: Size: p. 7143-7158 : , digital, PDF file.
• Bộ sưu tập: Metadata
• ID: 263686
• Chủ đề: 1. 09 biomass fuels; 2. 37 inorganic, organic, physical, and analytical chemistry; 3. 59 basic biological sciences; 4. 5-hydroxymethyl furfural (hmf); 5. Furfural

Tóm tắt

 There is increasing interest in the upgrading of C<
 sub>
 5<
 /sub>
  furfural (FF) and C<
 sub>
 6<
 /sub>
  5-hydroxymethyl furfural (HMF) into C<
 sub>
 10<
 /sub>
  and C<
 sub>
 12<
 /sub>
  furoins as higher energy-density intermediates for renewable chemicals, materials, and biofuels. This work utilizes the organocatalytic approach, using the in situ generated N,S-heterocyclic carbene catalyst derived from thiazolium ionic liquids (ILs), to achieve highly efficient self-coupling reactions of FF and HMF. Specifically, variations of the thiazolium IL structure have led to the most active and efficient catalyst system of the current series, which is derived from a new thiazolium IL carrying the electron-donating acetate group at the 5-ring position. For FF coupling by this IL (0.1 mol %, 60 �C, 1 h), when combined with Et<
 sub>
 3<
 /sub>
 N, furoin was obtained in >
 99% yield. A 97% yield of the C<
 sub>
 12<
 /sub>
  furoin was also achieved from the HMF coupling by this catalyst system (10 mol % loading, 120 �C, 3 h). On the other hand, the thiazolium IL bearing the electron-withdrawing group at the 5-ring position is the least active and efficient catalyst. The mechanistic aspects of the coupling reaction by the thiazolium catalyst system have also been examined and a mechanism has been proposed.