Hydrogenolysis of cellulose combining mineral acids and hydrogenation catalysts

A catalytic system capable of reaching high performance in the hydrogenolysis of cellulose at low reaction temperature and short reaction times has been developed. Therefore, supported noble metal catalysts based on Pt, Pd and Ru have been combined with dilute mineral acids. A broad variable set in terms of type of noble metal, type of acid, acid concentration and reaction time could be evaluated based on chemical interpretation and supported by a Design of Experiment (DoE) approach. The variables significantly influenced conversion of cellulose, product range and selectivity towards sugar alcohol formation. Thus, at 160 degrees C, above 60% yield in sugars and sugar alcohols with 84% selectivity at a cellulose conversion of 72% could be reached. Besides, glycerol, propylene glycol, ethylene glycol and methanol were formed as additional valuable by-products leading to an overall carbon utilization above 89%. Furthermore, the concept was successfully transferred to real feedstocks in the form of spruce reaching close to 60% conversion in only one hour reaction time.