XYLITOL PRODUCTION FROM XYLOSE OVER ZIRCONIA-DOPED SILICA SBA-15 SUPPORTED RUTHENIUM CATALYSTS

Abstract

Xylitol is an important product of xylan valorization — the main hemicellulose of birch and aspen wood. Xylitol is obtained by direct hydrogenation of xylose. In present study, the xylose was obtained by acid hydrolysis of birch wood xylan. The industrial catalyst for the xylitol production process is Raney nickel. Pyrophoricity, tendency to sintering, Ni leaching and contamination of the product are actual problems of its use. We have developed new supported ruthenium catalysts based on mesoporous silicate SBA-15 doped with zirconia. The proposed method of modification of SBA-15 by doping with zirconia improves the hydrothermal stability. The deposited Ru is present in the form of highly dispersed RuO2 particles and is distributed evenly. The catalysts are stable, safe and environmentally friendly. Their high catalytic activity allows the process to be carried out in very mild conditions – in pure water at 70 °C and a pressure of 5.5 MPa H2. While the catalysts provide 96-99% selectivity for xylitol. The introduction of the developed catalysts into the xylitol production might reduce the product purification cost of and the process energy consumption, thereby improving ecological and economic indicators of deep chemical processing of plant raw materials.