ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

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

E-mail: du661123@163.com

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.

DOI: 10.1515/chempap-2016-0101

Chemical Papers 70 (12) 1649–1657 (2016)