The hydrolysis-reduction of hemicellulose arabinogalactan to arabitol and galactitol polyalcohols, which are widely used in the food and pharmaceutical industries, was studied. It was shown that the process could be performed with the bifunctional catalyst containing highly dispersed ruthenium deposited on the cesium salt of silicon-tungsten heteropolyacid, Ru/Cs3HSiW12O40. The catalysts with different content of ruthenium (0.3, 0.6 and 1 wt.%) were synthesized for the study. The catalysts and their Cs3HSiW12O40 support were examined by various physicochemical methods (low-temperature nitrogen adsorption, IR spectroscopy, XRD, and TEM). The effect of temperature, substrate/catalyst ratio and ruthenium content in the catalyst on the yields of target products was elucidated. The highest yields of target products were achieved at the metal content of 0.6 wt.% and equal weights of the loaded catalyst and substrate (the 1:1 ratio). At a temperature of 200 °C, arabitol and galactitol can be produced with the yields up to 12 and 48 % for 2 h of the reaction in the presence of catalyst with the composition 0.6%Ru/Cs3HSiW12O40.
Cesium salt of 2-molybdo-10-tungstophosphoric acid as an efficient and reusable catalyst for the synthesis of uracil derivatives via a green route
