Mechanochemistry: a new approach to depolymerize cellulose via solid-solid reaction

Cellulose is both insoluble in water and resistant against hydrolysis. These features pose major problems for its conversion into platform chemicals, first of all glucose. Herein, is demonstrated that the combination of mechanical forces and the presence of solid acid catalysts leads to the full conversion of cellulose into oligosaccharides. In this way mechanochemistry results an available route to depolymerize cellulose via solid-solid reaction. In this work is described the whole developed methodology which permits to obtain a quantifiable final products from the milling of a cellulosic substrate. Furthermore is reported the analytic method constructed thanks to which it is possible to determine the cellulose conversion and thus compare the performances of various solid acids tested. This study has moreover allowed to understand important catalyst features that enhance the depolymerization rate, such as the distribution of the acid sites on a inert support. Amberlyst 15, producing 100% of oligosaccharides in 15 hours of milling at 500rpm, is resulted the more active catalysts among those studied. Thanks to its high activity were performed performances comparison of the different ball mills employed.