Process for the acid hydrolysis of polysaccharide-containing materials

摘要

In a process for the acid hydrolysis of polysaccharide-containing materials, especially for obtaining glucose from cellulose-containing raw materials, first the pentosans contained in the raw material are hydrolysed with concentrated orthophosphoric acid to pentoses and filtered off together with the orthophosphoric acid. The hexosans remaining in the filter cake are subsequently hydrolysed with pyrophosphoric acid, which has been obtained from the orthophosphoric acid by evaporation, to hexoses. The hexoses and pentoses are separated from the phosphoric acids by extraction with an organic solvent (for example butanol, isopropanol), the pyrophosphoric acid previously being converted back into orthophosphoric acid. Subsequently, the organic solvent is removed from the orthophosphoric acid by distillation and, just like the latter, used again. <IMAGE>