Heterogeneous Nb-containing catalyst/N,N-dimethylacetamide–salt mixtures: novel and efficient catalytic systems for the dehydration of fructose

Abstract

Development of efficient catalytic systems for dehydration of carbohydrates to produce 5-hydroxymethylfurfural (HMF) is a very attractive topic. In this work, we synthesized a novel Nb-containing catalyst by the reaction of niobium chloride and nitrilotris(methylenephosphonic acid) (NTMPA), denoted as Nb-NTMPA. The synthesized Nb-NTMPA was characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), N2 adsorption-desorption, and Fourier transform infrared spectroscopy and used as the heterogeneous catalyst for the dehydration of fructose into HMF using the mixture of N,N-dimethylacetamide (DMA) and salts as the reaction solvent. It was found that Nb-NTMPA was very active for the reaction and a HMF yield of 85.6% could be achieved in DMA-NaBr mixture at the optimal reaction conditions. Further study indicated that the salts could affect the activity of the reaction systems by the formation of DMA·M + (M=Li, Na and K) macrocations and weakly ion-paired halide ions. Moreover, Nb-NTMPA/DMA-salts systems could be also used in the production of HMF from inulin and sucrose with satisfactory yields.

Niobium phosphotungstates: excellent solid acid catalysts for the dehydration of fructose to 5-hydroxymethylfurfural under mild conditions

“…7 One of the key building blocks derived from carbohydrates is 5-hydroxymethylfurfural (5-HMF), which has been identied as one of the most important biomassderived platform compounds and is widely utilized in the synthesis of various chemicals. [8][9][10][11] A variety of catalysts, including both homogeneous and heterogeneous catalysts, have been employed for the conversion of fructose to obtain 5-HMF. Several homogeneous catalysts, such as mineral or organic acids, [12][13][14] Lewis acids, 15 inorganic salts, 16 and ionic liquids, [17][18][19] have been found to be effective for the synthesis of 5-HMF from fructose.…”

“…31,32 For instance, high yields (86.2%) of 5-HMF were achieved with a Nb 2 O 5 -catalyzed conversion of fructose in DMSO aer 2 h at 120 C. 33 Sulfated mesoporous niobium oxide provided a higher yield of 5-HMF (up to 88%) and showed better recyclability than what was observed with commercial Nb 2 O 5 . 34 Xue et al developed a novel Nb-containing catalyst by the reaction of niobium chloride and nitrilotris (methylenephosphonic acid), and that catalyst provided a 5-HMF yield of 85.6% from the dehydration of fructose in a DMA-NaBr mixture aer 1.5 h. 11 However, niobium compounds catalyst existed problems such as complex preparation, higher reaction temperature and the existence of by-products. Therefore, these ndings inspired us to develop a promising and readily prepared Nb-containing catalytic system for the conversion of fructose to 5-HMF under mild conditions (less than 100 C) with high throughput.…”

Reversibility of imido-based ionic liquids: a theoretical and experimental study

“…In the last few decades, ionic liquids (ILs), known as salts in liquid form at (or near) room-temperature, have been receiving signicant interest, with applications as engineering uids [1][2][3][4][5][6] and electrolytes [7][8][9] and for gas absorption [10][11][12][13][14] and biomass dissolution, [15][16][17] mainly because of their appealing properties such as low-melting points and exibilities in structure and function design. [18][19][20] Their properties can be tailored by incorporating anion and cation species and functional groups to serve certain purposes.…”

Liquid membrane catalytic model of hydrolyzing cellulose into 5-hydroxymethylfurfural based on the lattice Boltzmann method

“…2,3 In general, HMF is formed from fructose. [4][5][6] First, cellulose is converted into glucose through hydrolyzation. Then, the glucose is converted into fructose through isomerization.…”