Jump to main content
Jump to site search

Issue 20, 2017
Previous Article Next Article

An enhanced nonpolarity effect of silica-supported perfluoroalkyl sulfonylimide on catalytic fructose dehydration

Author affiliations

Abstract

–SO2NHSO2C4F9/CF3-functionalized silica was prepared. The preparation experiments introduced different amounts of –CH3 moieties to regulate the surface properties. Introduction of more –CH3 in the –SO2NHSO2C4F9 series brought about the materials' macroscopic hydrophobicity as expected, shown by the increased contact angle; but it was not so in the –SO2NHSO2CF3 series, which kept their hydrophilicity. In the application of fructose dehydration, the yields of HMF catalysed by the –C4F9-series catalysts were 10% higher than those by the –CF3-series catalysts at the same level of –CH3 introduced in 20% aqueous ethanol. This was due to their macroscopic hydrophobicity. However, the maximum amount of –CH3 introduced in both the –C4F9– and –CF3-series catalysts caused ca. 6% higher HMF yields, suggesting that the –CH3 moiety always promoted the dehydration. It was proposed that –CH3 changed the surface properties, even in the hydrophilic catalysts. This was confirmed by fluorescence spectrometry with pyrene as a probe molecule. An obvious enhancement of the surface nonpolarity in the introduction of a high amount of –CH3 was shown by the band III/I ratio of the spectra (0.60–0.83). The improved nonpolarity helped to repel water, both for the –C4F9– and –CF3-series catalysts. In particular, for the –C4F9 series, their water-repellent ability was strengthened, and the –C4F9 group preferably repelled the produced water away from the adjacent NH site. This could weaken HMF rehydration at the acid site. The regulation effect of –CH3 along with the enhancement caused by –C4F9 thus raised the total yield of HMF to ca. 15%. The enhanced nonpolarity effect by perfluoroalkyl around the acid site should be interesting to design new solid acids with hydrophilicity–hydrophobicity balance.

Graphical abstract: An enhanced nonpolarity effect of silica-supported perfluoroalkyl sulfonylimide on catalytic fructose dehydration

Back to tab navigation

Supplementary files

Publication details

The article was received on 05 Jul 2017, accepted on 04 Sep 2017 and first published on 05 Sep 2017


Article type: Paper
DOI: 10.1039/C7CY01340J
Citation: Catal. Sci. Technol., 2017,7, 4691-4699
  •   Request permissions

    An enhanced nonpolarity effect of silica-supported perfluoroalkyl sulfonylimide on catalytic fructose dehydration

    H. Zhang, Y. Cheng, H. Yuan, Y. Wang and Z. Ma, Catal. Sci. Technol., 2017, 7, 4691
    DOI: 10.1039/C7CY01340J

Search articles by author

Spotlight

Advertisements