In Situ Generated Dispersed Catalysts Based on Molybdenum and Tungsten Phosphides in Hydroprocessing of Guaiacol

Amorphous catalysts based on molybdenum and tungsten phosphides were prepared in situ from oil-soluble precursors such as triphenylphosphine and carbonyls of the corresponding metals during hydrodeoxygenation of guaiacol. These catalysts were characterized by powder X-ray diffraction, X-ray photoelectron spectroscopy, extended X-ray absorption fine structure spectroscopy, and transmission electron microscopy. After 6 h of reaction at 320–380°C and an initial hydrogen pressure of 5 MPa, the guaiacol conversion amounted to 89–91% in the presence of the molybdenum phosphide catalyst and 80–86% with tungsten phosphide. The selectivity towards phenol as the main reaction product reached as high as 80% in the presence of molybdenum phosphide (360°C, 6 h) and 78% in the tungsten phosphide case (340°C, 1 h). In the presence of both catalytic systems, the reaction products also contained anisole, cresols, and toluene.