Method for preparing a zeolite-based catalyst having an mfi structural code with improved density and mechanical strength

A process for preparing a catalyst in the form of an extrudate comprising an acidic MFI-type zeolite, the zeolite content being between 45% to 90% relative to the total mass of the catalyst, and a binder, and optionally containing a hydrogenating active phase, comprising the following steps:

• a) mixing of said MFI-type zeolite and of the binder, the average size of the elementary particles of said MFI-type zeolite measured by scanning electron microscopy being between 110 and 800 nm, to obtain a mixture,
• b) adding to said mixture obtained in step a) a peptizing agent selected from nitric acid and one or more carboxylic acids selected from acetic acid, citric acid and butyric acid, alone or as a mixture, to obtain a further mixture,
• c) adding to said further mixture obtained in step b) of a neutralizing agent selected from inorganic bases selected from sodium hydroxide, potassium hydroxide, and ammonia, alone or as a mixture, and organic bases in solution selected from amines and quaternary ammonium compounds, alone or as a mixture,
• d) shaping by extrusion the resultant mixture obtained in step c) to obtain a solid,
• e) optionally, drying the solid obtained in step d),
• f) heat-treating said solid obtained in step d) or e) in the presence of steam at a temperature of between 400 and 1000° C. and in the presence of a stream of air containing from 1% to 60% by volume of water, and
• g) optionally, introducing of one or more precursors of a hydrogenating active phase into the solid obtained in step f).