Synthesis of alcohols and diols by hydrogenation of carboxylic acids and esters over RuSn-Al2O3 catalysts

RuSn-Al2O3 catalysts were prepared by sol-gel, impregnation and their combination methods and the relationship between catalyst properties and reaction profiles in the hydrogenation of dicarboxylic acids and saturated fatty acids were examined. The surface Sn contents of catalysts characterized by X-ray photoelectron spectroscopy (XPS) depended on the preparation method in spite of almost the same bulk Ru and Sn compositions measured by X-ray fluorescence analyses. Temperature programmed reduction (TPR) and CO adsorption of the catalysts also depended on preparation methods. The preparation method, Sn/Ru ratio, reaction temperature and the structure of substrate have influence on the yield of diol. Ru-Sn-Al2O3 catalysts gave fatty alcohols with good yield in the hydrogenation of the corresponding saturated fatty acids. The conversion of the acids increased with increase in their carbon number. (C) 1999 Elsevier Science B.V. All rights reserved.