One-pot production of isosorbide from glucose using a dual functional catalyst based on sugarcane leaf biochar and mixed with Amberlyst-15

Isosorbide (ISB), a rigid bicyclic diol derived from glucose, is an attractive bio-based monomer for sustainable polymers, but its production typically relies on multi-step processes and fossil-based catalysts. Herein, a one-pot route producing ISB directly from glucose is demonstrated using a dual functional catalytic system comprising sulfonated Ru catalyst supported on a sugarcane leaf biochar (Ru-S-CSCL) physically mixed with Amberlyst-15. Ru-S-CSCL containing 1–6 wt% Ru was prepared; the 5 wt% catalyst (5Ru-S-CSCL) was fully characterized and combined with Amberlyst-15 at various weight ratios (0:50–50:0). Glucose (0.5–2.5 g), mixed catalyst (10–60 wt%), and water were reacted at 160–240 °C under 1–6 MPa H 2 for 12–24 h. The best performance, with an ISB yield of 50.12% and selectivity of 50.91%, was achieved using 1 g glucose, 0.25 g 5Ru-S-CSCL, and 0.25 g Amberlyst-15 (total catalyst loading of 50 wt%) at 220 °C for 18 h under 5 MPa H 2 . Characterization indicates that the synergy between Ru hydrogenation sites and sulfonic acid groups is critical for efficient one-pot ISB formation. Catalyst reusability was further evaluated under the optimum reaction conditions, revealing a gradual decline in catalytic activity, which was mainly attributed to the partial leaching of Ru and sulfonic acid groups, resulting in catalyst deactivation. The applicability of the catalytic system was further demonstrated by extending the process to ISB production from microcrystalline cellulose and pretreated SCL. These results demonstrate that SCL-derived biochar is a competitive and sustainable catalyst support for one-pot ISB production from renewable biomass.