Method for the preparation of defect-free nanosized synthetic zeolite materials

A method for the preparation of a defect-free synthetic zeolite material in the form of monodisperse single nanocrystals having a size ranging from 10 to 400 nm, the defect-free synthetic zeolite material having a MFI-, BEA- or MEL- framework type and a silicon to metal M molar ratio Si/M ranging from 179 to 65440, the metal M being selected from W, V, Mo, Sn and Zr, the method comprising:

• 1) contacting at least one source of silicon, at least one source of alkali metal M′ selected from Na and K, at least one source of metal M selected from W, V, Mo, Sn and Zr, at least one tetraalkylammonium hydroxide structure-directing agent and water, so as to obtain a clear aqueous suspension having the following molar composition:
• xMnOm:25SiO2:yTAA2O:zM′2O:uH2O (I)
• in which:
• 0.01≤x≤1.5,
• 2≤y≤9,
• 0.01≤z≤4,
• 300≤u≤3000,
• n is an integer equal to 1 or 2, and
• m is an integer and 2≤m≤5;
• 2) aging the resulting clear suspension of step 1) at a temperature ranging from 20° C. to 30° C.;
• 3) heating the resulting clear suspension at a temperature ranging from 40° C. to 180° C. so as to form a dispersion of a solid comprising monodisperse single nanocrystals of the synthetic zeolite material in a liquid;
• 4) separating and recovering the solid from the liquid;
• and
• 5) calcining the solid so as to obtain the synthetic zeolite material in the form of monodisperse single nanocrystals.