ISSN print edition: 0366-6352
ISSN electronic edition: 1336-9075
Registr. No.: MK SR 9/7
Synthesis of 5-hydroxymethylfurfural from glucose in a biphasic medium with AlCl3 and boric acid as the catalyst
Zhi-Lei Xu, Xiao-Yue Wang, Mei-Yu Shen, and Chang-Hai Du
School of Chemical Engineering, Changchun University of Technology, Changchun 130012, Jilin, China
Abstract: In combination with non-corrosive and low-toxic boric acid, AlCl3 ·6H2O was found to be effective for the synthesis of 5-hydroxymethylfurfural (5-HMF) from glucose. In this work, a 5-HMF yield of ≈ 60 % was obtained at 170°C for 40 min in a H2O/THF biphasic solvent mixture. An addition of NaCl not only improved the partition coefficients but also inhibited by-product formation. THF was identified as an ideal extraction solvent in biphasic systems containing C4 solvents. However, low concentration of ZnCl2, CoCl2·6H2O, MnCl2 ·4H2O, NiCl2 ·6H2O, FeCl3 ·6H2O were not suitable for the catalyst system, while ZrOCl2 ·8H2O, InCl3 ·4H2O showed high activity for the reaction. Boric acid increased the amount of Lewis acid sites in the reactive phase and enhanced the isomerization of glucose to fructose. A mechanism of the AlCl3 ·6H2O and boric acid catalyzed glucose dehydration reaction was proposed to proceed through the isomerization of glucose to fructose followed by the transformation of fructose to 5-HMF.
Keywords: boric acid; AlCl3 ·6H2O; 5-hydroxymethylfurfural; glucose
Full paper is available at www.springerlink.com.
Chemical Papers 70 (12) 1649–1657 (2016)