Selective conversion of fructose to fuels and fine chemicals is an important step for biomass utilization. In this paper, direct conversion of fructose to 2,5-dihydroxymethylfuran and 2,5dimethylfuran was first realized over combined HY zeolite and inexpensive hydrotalcite (HT)-Cu/ ZnO/Al 2 O 3 in a fixed-bed reactor. The cooperative effect of HY zeolite and γ-butyrolactone solvent facilitated the dehydration of fructose into 5-hydroxymethylfurfural. By adjusting the hydrogenation temperature for HMF over HT-Cu/ZnO/Al 2 O 3 catalyst, high yields of 2,5-dihydroxymethylfuran (48.2%) at 140 °C and 2,5-dimethylfuran (40.6%) at 240 °C were obtained, respectively.
Two kinds of typical mineral‐derived Cu/ZnO catalysts consisting of aurichalcite and zincian malachite were introduced for furfural hydrogenation to furfuryl alcohol (FOL) and 2‐methylfuran (2‐MF) in a fixed‐bed reactor. Under proper reaction conditions, high yields of FOL (above 99 %) and 2‐MF (94.5 %) could be obtained over the aurichalcite Cu/ZnO catalyst (AC‐CZ), whereas the best yield of 2‐MF was only 76.9 % (0.5 h−1) over the zincian malachite Cu/ZnO catalyst (ZM‐CZ). The normalized productivity of 2‐MF was 43.5 mol kgCu−1 h−1 and 17.4 mol kgCu−1 h−1 for AC‐CZ and ZM‐CZ, respectively (LHSV=1.5 h−1). The catalysts were characterized by XRD analysis, Raman spectra, CO IR spectroscopy, H2 temperature‐programmed reduction, N2O titration, NH3 temperature‐programmed desorption, and X‐ray photoelectron spectroscopy. The far better performance of AC‐CZ in furfural hydrogenation was ascribed to its higher dispersion of copper species, superior copper surface area, better surface acidity distribution, and stronger Cu0–ZnO synergy. In addition, the surface acidity of the catalysts seemed to have a higher influence on 2‐MF production than the Cu surface area, but the optimal balance of both factors still needs to be investigated systematically.
The method for producing polyvinyl alcohol (PVA) by the solution polymerization of vinyl acetate first and then alcoholysis strategy is industrial. Where solvent plays a vital role in control over stereoregularity, molecular weight and its distribution, crystallinity and so on. In this report, when methyl acetate was used as a solvent in the polymerization of vinyl acetate instead of methanol, prepared PVA was characterized by Fourier-transform infrared spectroscopy (FT-IR), nuclear magnetic resonance (NMR), gel permeation chromatography (GPC), thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The results showed that PVA obtained in methyl acetate has a higher content of syndiotactic structure, crystallinity melting temperature and enhanced thermal stability compared with PVA obtained in methanol due to the formation of Π -Π complex between methyl acetate and vinyl acetate and the enhanced steric hindrance effect during polymerization. Additionally, methyl acetate has a smaller chain transfer constant (1.31 Â 10 À4 ), which benefits to decrease the branching degree and molecular weight distribution index of PVA. This research provides more ideas for the choice of solvents in the industrial production of polyvinyl alcohol.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.