Synthesis and activity of a new catalyst for hydroprocessing: Tungsten phosphide

A tungsten phosphide, WP, hydrotreating catalyst was prepared by temperatur e-programmed reduction of an X-ray amorphous tungsten phosphate at a heatin g rate of 0.0167 K s(-1) and a 2-h soak at the final temperature of 938 K. Characterization of intermediates quenched at different temperatures reveal ed a single crystalline reaction product whose specific CO uptake and BET s urface areas passed through a maximum of 12 mu mol g(-1) and 15 m(2) g(-1), respectively, at 873 K. Heating rate variation measurements gave an appare nt first-order activation energy of 148 kJ mol(-1) for the reduction. Tungs ten phosphide was catalytically active in the hydrodenitrogenation and hydr odesulfurization reactions of a simulated light oil consisting of 20 wt% te tralin, 76 wt% tetradecane, 2000 wppm N as quinoline, 3000 wppm S as dibenz othiophene, and 500 wppm O as benzofuran. Measurements were made in an upfl ow fixed-bed reactor operated at 3.1 MPa and 643 K and gave conversion leve ls at steady state for the WP catalyst of 58% HDN and 67% HDS. These conver sions were superior to those found for WC, W2N, and WS2 tested under the sa me conditions. (C) 2001 Academic Press.