Influence of Water-Miscible Organic Solvent on the Activity and Stability of Silica-Coated Ru Catalysts in the Selective Hydrolytic Hydrogenation of Cellobiose into Sorbitol

Tommy Haynes,Sophie Hermans,Samuel Carlier,Vincent Dubois,Sharon Hubert

doi:10.3390/catal10020149

Tommy Haynes, Sophie Hermans + Show 3 more

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https://doi.org/10.3390/catal10020149

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Abstract

Ruthenium nanoparticles supported on carbon black were coated by mesoporous protective silica layers (Ru/CB@SiO2) with different textural properties (SBET: 280–390 m2/g, pore diameter: 3.4–5.0 nm) and were tested in the selective hydrogenation of glucose into sorbitol. The influence of key parameters such as the protective layer pore size and the solvent nature were investigated. X-ray photoelectron spectroscopy (XPS) analyses proved that the hydrothermal stability was highly improved in ethanolic solution with low water content (silica loss: 99% in water and 32% in ethanolic solution). In this work, the strong influence of the silica layer pore sizes on the selectivity of the reaction (shifting from 4% to 68% by increasing the pores sizes from 3.4 to 5 nm) was also highlighted. Finally, by adding acidic co-catalyst (CB–SO3H), sorbitol was obtained directly through the hydrolytic hydrogenation of cellobiose (used as a model molecule of cellulose), demonstrating the high potential of the present methodology to produce active catalysts in biomass transformations.

Highlights

For many years, the conversion of lignocellulosic biomass, an environmentally friendly and sustainable alternative resource to fossil fuels, into valuable chemicals and biofuels has drawn a lot of attention [1]
We propose to cover heterogeneous catalysts by by protective mesoporous silica layers with differentstructural structuralproperties propertiesand andto to evaluate evaluate their their protective mesoporous silica layers with different performances in the one-pot conversion of cellobiose into sorbitol in water-miscible organic solvents performances in the one-pot conversion of cellobiose into sorbitol in water-miscible organic solvents (Figure 1)
X-ray photoelectron spectroscopy (XPS), nitrogen physisorption, and scanning electron microscopy (SEM)-EDX in order to identify the influence of their physicochemical characteristics on hydrothermal stability and activity in a biomass model reaction: the hydrolytic hydrogenation of cellobiose into sorbitol

Summary

Introduction

The conversion of lignocellulosic biomass, an environmentally friendly and sustainable alternative resource to fossil fuels, into valuable chemicals and biofuels has drawn a lot of attention [1]. Cellulose, the main component of such biomass, has been widely studied and converted into various products such as hydrocarbons, oxygenated bio-oil, and sugar alcohols [2,3]. Enzymatic catalysis and fermentation allow breaking down cellulose and converting it into commodity chemicals [4]. Such biological processes suffer from limitations such as low efficiencies, limited scale of production, and narrow reaction conditions. Cellulose valorization transformations have been recently oriented toward solid heterogeneous catalysts. All these transformations are usually performed in aqueous media at higher temperature, implying the possible sintering of the catalytic active phase [5] and other deactivation processes

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