TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Components: The inorganic molten salt hydrate comprises zinc chloride, calcium chloride or lithium chloride. The hydrogenation catalyst comprises a noble transition metal, which is ruthenium. The hydrogenation catalyst comprises activated carbon as a carrier. The inorganic molten salt medium comprises at least 60 wt.% zinc chloride.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Process: The polysaccharide-containing material comprises lignocellulose or hemicellulose, where lignin or hemicellulose is removed from the inorganic molten salt medium before the step (b). The step (b) is conducted in the substantial absence of hemicellulose. The step (b) is carried out in the presence of an acidic catalyst. The step (c) is carried out in the presence of a hydrogenation catalyst. In the step (d), the selectivity to the formation of dianhydro sugar is at least 80%. The process further comprises derivatizing in the inorganic molten salt medium, the hydroxyl groups of the dianhydro sugars to form derivatized dianhydro sugars having reduced solubility in the inorganic molten salt medium. The derivatization comprises etherification (preferred) or esterification. Preferred Components: The acidic catalyst is a mineral acid (hydrochloric acid), where the step (b) is carried out in the absence of mineral acid. The monosaccharide comprises or consists essentially of glucose. The sugar alcohol comprises or consists substantially of sorbitol. EXAMPLE - Ball milled pine wood samples (containing lignocellulosic biomass) (0.5 g) were mixed with 6.0 g of salt solution with 70 wt.% of zinc chloride and hydrochloric acid content of 0.4 molal. The reaction was effected for 90 minutes. The product was ultracentrifuged and full separation of a black/violet material (lignin) at the top and a clear salt/sugar solution at the bottom was obtained. When salt solutions were dissolved in 10 times the water weight, no cellulose precipitated, indicating the full conversion of cellulose and hemicellulose to the corresponding monosaccharide sugars and separation of lignin from the sugars.