Deep eutectic solvent-assisted fabrication of zirconium phytate thin nanosheets for important biomass transformations

Abstract

Utilization of naturally occurring resources to construct functional catalytic materials is significantly important, and facile and environmental-benign strategies are highly desired to afford the materials having a specific structure and good catalytic activity. Herein, we reported an innovative deep eutectic solvent (DES)-assisted strategy to synthesize zirconium phytate with a thin nanosheet structure (denoted as Zr-Phy-DES) using plant-originated phytic acid (PhyA) as the renewable building block. This strategy was eco-friendly and adjustable owing to the designability of DESs. The Zr-Phy-DES as an acidic catalyst showed high activity on two important biomass transformations, i.e., dehydration of carbohydrates and Meerwein-Ponndorf-Verley reduction of ethyl levulinate. Interestingly, Zr-Phy-DES showed higher catalytic performance than the zirconium phytates prepared in ethylene glycol and N,N-dimethylformamide, confirming the advantage of DESs for preparing functional materials. Notably, the unique feature of this proposed strategy is that renewable catalysts are prepared in an environmental-benign solvent for efficiently catalyzing biomass transformation.

Keywords: chemistry; green chemistry; materials chemistry; materials science; organic chemistry.

Graphical abstract

Figure 1

The morphology of the zirconium phytates prepared in different solvents (A–F) SEM (A, C, and E) and TEM (B, D, and F) images of the synthesized zirconium phytates. Zr-Phy-DES (A, and B), Zr-Phy-EG (C, and D), and Zr-Phy-DMF (E, and F).

Figure 2

Characterization of the synthesized zirconium phytates (A–E) (A) XRD patterns, (B) FT-IR spectra, (C) N₂ adsorption-desorption isotherms, (D) XPS spectra of Zr 3days, and (E) XPS spectra of P 2p.

Figure 3

Optimization of reaction conditions for dehydration of fructose (A–D) (A) Effect of reaction temperature, (B) Influence of reaction time, (C) Effect of Zr-Phy-DES usage, and (D) Recyclability of Zr-Phy-DES/[Bmim]Cl catalytic system. Reaction conditions: fructose, 0.1 g; [Bmim]Cl, 1 g; Zr-Phy-DES, 0.05 g for A, B, and D; reaction temperature, 100 °C for B-D; reaction time, 2 h for A, C, and D.

Figure 4

The correlation between the catalytic activity and the acidity

Scheme 1

The possible catalytic mechanism for Zr-Phy-DES-catalyzed MPV reduction of EL to produce GVL