US Patent No : 6177374

This invention relates to the synthesis of a crystalline synthetic catalyst having the general formula expressed in the form of oxides: M 2/n o. x Al2O3 Y SiO2, Z ZnO wherein, M represents a proton and/or a metallic cation, n is the valence of the said cation, Y/x is a number ranging from 5 to 1000 (SiO2/Al2O3 molar ratio), and a process for preparing such catalyst by (a) forming a reaction medium comprising water, a silicon source, an aluminium source, a zinc source and a source of structure directing agent capable of providing organic cations, (b) heating the said reaction mixture to a temperature ranging from 80° C. to 230° C. at autogeneous phase, and (c) heating the solid content obtained at the end of step (b) to a temperature greater than 400° C., so as to eliminate the organic species present due to the use of the structuring agent.