Cellulose deconstruction at 428 K was studied in biphasic reaction systems consisting of GVL and aqueous solutions containing HCl (0.1-1.25 M) and a solute, such as salt or sugar. This biphasic system achieves high yields of levulinic and formic acids (e.g., 70%), and leads to complete solubilization of cellulose. The GVL solvent extracts the majority of the levulinic acid (e.g., greater than 75%), which can subsequently be converted to GVL over a carbon-supported Ru-Sn catalyst. This approach for cellulose conversion eliminates the need to separate the final product from the solvent, because the GVL product is the solvent. In addition, this approach eliminates the deposition of solid humin species in the cellulose deconstruction reactor, allowing these species to be collected and used for other processing options.