Isosorbide synthesis from cellulose with an efficient and recyclable ruthenium catalystElectronic supplementary information (ESI) available: General experimental details, optimization of one-step reactions, optimization of two-step reactions, catalyst characterization, catalysts on sulfonated carbon. See DOI: 10.1039/c7gc01821e

Herein, we describe an efficient two-step pathway for isosorbide synthesis from cellulose with the use of new recyclable Ru-catalysts. We show that the oxidative and sulfonation treatments of the new Ru-catalysts increase the acidity and the hydrophilicity of the activated carbon support material, thus reducing the catalyst fouling caused by the build-up of insoluble products. Accordingly, the new Ru-catalysts are more resilient towards lignin containing cellulose than a commercial Ru/C catalyst, and the best Ru-catalyst maintains its high catalytic activity in four consecutive runs with dissolving pulp, microcrystalline cellulose and even with residual lignin containing bagasse pulp. Overall, our two-step approach provides isosorbide in high yields of 56-57 mol% (49-50 wt% of the substrate) from the cellulosic substrates. A recyclable Ru-based hydrogenation catalyst for the two-step conversion of lignocellulosic substrates into isosorbide.