Hidrodesoxigenação de fenol em catalisadores a base de fosfetos de metais de transição mássicos

Abstract

Five different unsupported transition metal phosphides were synthesized in order to evaluate their catalytic activity in hydrodeoxygenation of phenol, a bio-oil model molecule. The Ni2P, CoP, FeP, MoP and WP phases were prepared in two steps: synthesis of phosphates by the calcination of products from reactions between metallic precursors and dibasic ammonium phosphate, and temperature programmed reduction of these phosphates. Those materials were characterized by in situ x-ray diffractometry (except WP, analyzed ex situ), temperature programmed reduction and CO chemisorption. These characterizations allowed the identification of desired phases after synthesis, the calculation of the intrinsic reaction rate and the definition of catalysts’ activation parameters, besides helping to understand activation route of these catalysts. Catalytic evaluation tests were carried out in a continuous reactor, gas phase, at ambient pressure, 300 ° C and 30 mL min-1 of reactants, which consisted of a mixture of phenol and hydrogen in a H2/C6H5OH = 60 molar ratio. All catalysts promoted high selectivity to direct deoxygenation route’s products, highlighting Ni2P (94,6 % of benzene). Besides that, Ni2P e FeP were identified as the most active catalysts in the reaction.