Kristalliner synthetischer Zeolith

Crystalline aluminosilicate zeolite having a fanjasite structure of Si, Al, O, alkali metal and H+ and/or NH4+ ions (see Division C1) may be modified for use as a hydrocracking catalyst for feedstocks such as cycle oil by impregnating with Pd, Pt, Rh, Mb, Cr, V, Co, Ni, Cu, Ag or Mn in amount 0.01 to 5.0 weight per cent based on the dry zeolite.ALSO:Crystalline aluminosilicate zeolites having a fanjasite structure of Si, Al, O, alkali metal and hydrogen-containing ions (i.e. H+ of NH4+) are characterized by cage and bridge cation positions which are predominately occupied by the hydrogen-containing ions and alkali metal ions respectively wherein the electron density at the bridge position is 1.0 to 2.0 electrons per cubic Angstrom and the electron density at the cage position is less than 75% of the value corresponding to complete occupancy of the cage position by alkali metal ions. A synthetic fanjasite of the formula 0.9\sB0.2 M2O : Al2O3 : xSiO2 when in the anhydrous form where M = alkali metal and x is >2.5 may be contacted with a solution of (NH4)2CO3 or NH4NO3 selectively to replace the cage M+ by NH4+ leaving M+ at the bridge positions. Alternatively, all the M+ may be replaced by treatment with other reagents, e.g. NH4Cl and the bridge M+ reintroduced by reaction with aqueous alkali metal hydroxide. Ammonium cations may be decomposed to hydrogen ions by calcination at about 1000 DEG F.