Method for preparing a nanometric zeolite Y

1. A method for preparation of a FAU-structural nanometric zeolite Y that has a crystal size of less than 100 nm and an Si/Al ratio that is greater than 2, with said method comprising at least the following:

i) mixing, in aqueous medium, of at least one AO 2 source of at least one tetravalent element A that is silicon, germanium, or titanium, by itself or in a mixture, at least one BO b source of at least one trivalent element B that is aluminum, boron, iron, indium, or gallium, by itself or in a mixture, at least one C 2/m O source of an alkaline metal or alkaline-earth metal C that is lithium, sodium, potassium, calcium, or magnesium, by itself or in a mixture, with said C 2/m O source of alkaline metal or alkaline-earth metal C also comprising at least one hydroxide ion source, obtaining a gel, with the reaction mixture having the following molar composition:

v AO 2 : w BO b : x C 2/m O: y H 2 O

with v being between 1 and 40,

with w being between 0.1 and 5,

with x being between 1 and 40,

with y being between 30 and 1000,

with b being between 1 and 3, b being a whole number or a rational number,

with m being equal to 1 or 2,

ii) curing of the gel obtained at the end of (i) at a temperature of between −15° C. and 60° C., with or without stirring, for a time period of between 1and 60 days,

iii) after at least 3 days of curing, a step consisting of a one-time or repeated addition of at least one AO 2 source of at least one tetravalent element A that is silicon, germanium, or titanium, by itself or in a mixture, in said gel, with the molar composition of the gel at the end of the addition being as follows:

v AO 2 :w BO b :x C 2/m O: y H 2 O

with v being between 5 and 50,

with w being between 0.1 and 5,

with x being between 1 and 40,

with y being between 200 and 1000,

with b being between 1 and 3, b being a whole number or a rational number,

with m being equal to 1 or 2,

(iv) hydrothermal treatment of the gel that is obtained at the end of (iii) at a temperature of between 20° C. and 200° C., under autogenous reaction pressure, for a time period of between 1 hour and 14 days, to obtain crystallization of said FAU-structural nanometric zeolite Y.

2. The method according to claim 1 , in which A is silicon.

3. The method according to claim 1 , in which B is aluminum.

4. The method according to claim 1 , in which C is sodium.

5. The method according to claim 1 , in which the reaction mixture in (i) has the following molar composition:

v AO 2 : w BO b : x C 2/m O: y H 2 O

with v being between 15 and 20,

with w being between 0.2 and 1.5,

with x being between 1 and 20,

with y being between 100 and 400,

with b being between 1 and 3, b being a whole number or a rational number,

with m being equal to 1 or 2,

where A, B and C have the same definition as above.

6. The method according to claim 1 , in which seeds comprising FAU-structural zeolite crystals are added during mixing in (i).

7. The method according to claim 1 , in which the tetravalent element A added in curing in (iii) is identical to the tetravalent element A that is added in mixing in (i).

8. The method according to claim 1 , in which the one-time or repeated addition of at least one source of at least one tetravalent element A is carried out during the curing (ii).

9. The method according to claim 8 , in which the one-time or repeated addition of at least one source of at least one tetravalent element A is carried out after at least 5 days of curing.

10. The method according to claim 1 , in which the one-time or repeated addition of at least one source of at least one tetravalent element A is carried out after curing in (ii).

11. The method according to claim 1 , in which the molar composition of the gel at the end of the addition in (iii) is as follows:

v AO 2 : w BO b : x C 2/m O: y H 2 O

with v being between 20 and 30,

with w being between 0.2 and 1.5,

with x being between 1 and 20,

with y being between 200 and 500,

with b being between 1 and 3, b being a whole number or a rational number,

with m being equal to 1 or 2,

where A, B and C have the same definition as above.

12. The method according to claim 1 , in which the FAU-structural nanometric zeolite Y that is formed at the end of (iv) is filtered, washed, and then dried at a temperature of between 20° C. and 150° C.

13. The method according to claim 12 , in which said zeolite that is obtained at the end of drying undergoes at least one calcination and at least one ion exchange.

14. The method according to claim 1 , in which the tetravalent element A added in curing in (iii) is different from the tetravalent element A that is added in mixing in (i).

15. The method according to claim 1 , wherein (iii) consists of, after at least 3 days of curing, one time addition of and AO 2 source of one tetravalent element A.

16. A method for preparation of a FAU-structural nanometric zeolite Y that has a crystal size of less than 100 nm and an Si/Al ratio that is greater than 2, with said method consisting of:

i) mixing, in aqueous medium, of at least one AO 2 source of at least one tetravalent element A that is silicon, germanium, or titanium, by itself or in a mixture, at least one BO b source of at least one trivalent element B that is aluminum, boron, iron, indium, or gallium, by itself or in a mixture, at least one C 2/m O source of an alkaline metal or alkaline-earth metal C that is lithium, sodium, potassium, calcium, or magnesium, by itself or in a mixture, with said C 2/m O source of alkaline metal or alkaline-earth metal C also comprising at least one hydroxide ion source, obtaining a gel, with the reaction mixture having the following molar composition:

v AO 2 : w BO b : x C 2/m O: y H 2 O

with v being between 1 and 40,

with w being between 0.1 and 5,

with x being between 1 and 40,

with y being between 30 and 1000,

with b being between 1 and 3, b being a whole number or a rational number,

with m being equal to 1 or 2,

ii) curing of the gel obtained at the end of (i) at a temperature of between −15° C. and 60° C., with or without stirring, for a time period of between 1and 60 days,

iii) after at least 3 days of curing, a one-time or repeated addition of at least one AO 2 source of at least one tetravalent element A that is silicon, germanium, or titanium, by itself or in a mixture, in said gel, with the molar composition of the gel at the end of the addition being as follows:

v AO 2 : w BO b : x C 2/m O: y H 2 O

with v being between 5 and 50,

with w being between 0.1 and 5,

with x being between 1 and 40,

with y being between 200 and 1000,

with b being between 1 and 3, b being a whole number or a rational number,

with m being equal to 1 or 2,

(iv) hydrothermal treatment of the gel that is obtained at the end of (iii) at a temperature of between 20° C. and 200° C., under autogenous reaction pressure, for a time period of between 1 hour and 14 days, to obtain crystallization of said FAU-structural nanometric zeolite Y.