Binder effect on the catalytic activity of MoO3 bulk catalyst reduced by H2 for n-heptane hydroisomerization

Two bulk catalysts containing about 70 wt.% of molybdenum trioxide and alumina or silica as binder were prepared by a gel method. They were characterized by X-ray diffraction, Raman spectroscopy, TGA in air and textural properties. The MoO3 bulk catalysts were activated in situ by reduction with hydrogen and tested in the hydroisomerization of n-heptane using a fixed bed continuous flow microreactor coupled to gas chromatograph. The highest catalytic activity for hydroisomerization was obtained with the alumina-based bulk catalyst, although the silica-based bulk catalyst showed lower amounts of cracking products and a higher selectivity to dimethylpentanes. The bulk catalysts resulted more active than MoO3 powder. The results indicate that the acid–base properties of the binder have a desirable effect on the acidity of the molybdenum trioxide powder as hydroisomerization catalyst.