Wahachiro Tanimura

On the Manufacture of Xylitol from Xylose

Xylitol was prepared by means of high pressure hydrogenation of xylose solution using Raney-nickel catalyst. The present investigation was undertaken to determine the optimum conditions with regard to temperature, concentration of xylose, the amount of catalyst and pressure. The freshly obtaind xylitol solution has a small amount of inorganic salts which act as the catalyst poison, so these are removed by passing the solution through ion exchange resin. Xylose solution (as 99.5% xylose) and Raney-nickel are then placed in the auto-slave and agitated. The following conditions was revealed to be most appropriate; 1) Temperature, 95_??_124°C. 2) Concentration, 30_??_35% xylose solution (25g xylose). 3) Amount of catalyst, 20% Raney-nickel for sample. 4) Pressure, 40 kg/cm2. The yield of xylitol was 96_??_98%. The deionized xylitol solution was made to Brix. 70°by evaporating at 45 to 50°C, under 60 to 80mmHg.