Process for preparing a catalyst based on izm-2 from a solution comprising specific precursors and use for the isomerization of paraffinic feedstocks

Process for preparing a difunctional catalyst comprising an acid function constituted by zeolite IZM-2, a hydrogenating function comprising at least one noble metal from group VIII of the Periodic Table, chosen from platinum and palladium, and a matrix, said process comprising at least the following steps:

• i) a step of preparing the support for the catalyst by forming zeolite IZM-2 with a matrix,
• ii) a step of depositing at least one noble metal from group VIII of the Periodic Table by impregnation of the support prepared in step i) with an aqueous solution comprising
• at least one ammoniacal compound chosen from the platinum(II) tetramine salts of formula Pt(NH3)4(OH)2, Pt(NH3)4(NO3)2 or Pt(NH3)4X2, the platinum(IV) hexamine salts of formula Pt(NH3)6X4;
• the platinum(IV) halopentamine salts of formula (PtX(NH3)5)X3;
• the platinum N-tetrahalodiamine salts of formula PtX4(NH3)2;
• and the halogenated compounds of formula H(Pt(acac)2X);
• the palladium(II) salts of formula Pd(NH3)4SO4 or Pd(NH3)4X2, X being a halogen chosen from chlorine, fluorine, bromine and iodine, and “acac” representing the acetylacetonate group,
• and at least one ammonium salt chosen from ammonium nitrate NH4NO3, ammonium chloride NH4Cl, ammonium hydroxide NH4OH, ammonium bicarbonate NH4HCO3 and ammonium acetate NH4H3C2O2, alone or as a mixture,
• the mole ratio between the ammonium salt and the noble metal being between 0.1 and 400.